Author name code: chen
ADS astronomy entries on 2022-09-14
author:"Chen, Peng-Fei" OR author:"Chen, Peng Fei"
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Title: J-PLUS: a catalogue of globular cluster candidates around
the M 81/M 82/NGC 3077 triplet of galaxies
Authors: Chies-Santos, Ana L.; de Souza, Rafael S.; Caso, Juan P.;
Ennis, Ana I.; de Souza, Camila P. E.; Barbosa, Renan S.; Chen, Peng;
Javier Cenarro, A.; Ederoclite, Alessandro; Cristóbal-Hornillos,
David; Hernández-Monteagudo, Carlos; López-Sanjuan, Carlos;
Marín-Franch, Antonio; Moles, Mariano; Varela, Jesús; Vázquez
Ramió, Héctor; Dupke, Renato; Sodré, Laerte; Angulo, Raul E.
Bibcode: 2022MNRAS.516.1320C
Altcode: 2022arXiv220211472C
Globular clusters (GCs) are proxies of the formation assemblies of
their host galaxies. However, few studies exist targeting GC systems
of spiral galaxies up to several effective radii. Through 12-band
Javalambre Photometric Local Universe Survey (J-PLUS) imaging, we study
the point sources around the M 81/M 82/NGC 3077 triplet in search of new
GC candidates. We develop a tailored classification scheme to search for
GC candidates based on their similarity to known GCs via a principal
component analysis projection. Our method accounts for missing data
and photometric errors. We report 642 new GC candidates in a region
of 3.5 deg2 around the triplet, ranked according to their
Gaia astrometric proper motions when available. We find tantalizing
evidence for an overdensity of GC candidate sources forming a bridge
connecting M 81 and M 82. Finally, the spatial distribution of the GC
candidates (g - i) colours is consistent with halo/intra-cluster GCs,
i.e. it gets bluer as they get further from the closest galaxy in the
field. We further employ a regression-tree-based model to estimate the
metallicity distribution of the GC candidates based on their J-PLUS
bands. The metallicity distribution of the sample candidates is broad
and displays a bump towards the metal-rich end. Our list increases
the population of GC candidates around the triplet by threefold,
stresses the usefulness of multiband surveys in finding these objects,
and provides a testbed for further studies analysing their spatial
distribution around nearby (spirals) galaxies.
Title: Prominence oscillations activated by an EUV wave
Authors: Devi, Pooja; Chandra, Ramesh; Joshi, Reetika; Chen, P. F.;
Schmieder, Brigitte; Uddin, Wahab; Moon, Yong-Jae
Bibcode: 2022AdSpR..70.1592D
Altcode: 2022arXiv220213147D
Prominence oscillations are one of interesting phenomena in the solar
atmosphere, which can be utilized to infer the embedded magnetic field
magnitude. We present here the transverse oscillations of two different
prominences located at the East solar limb on 2011 February 11 using the
multi-wavebands data of the Atmospheric Imaging Assembly (AIA) on-board
the Solar Dynamics Observatory (SDO) satellite. A prominence eruption
was observed towards the east direction with an average speed of ≈
275 km s-1. The eruption is fitted with the combination of
a linear and an exponential functions of time. An extreme ultraviolet
(EUV) wave event was associated with the prominence eruption. This EUV
wave triggered the oscillations of both prominences on the East limb. We
computed the period of each prominence using the wavelet analysis
method. The oscillation period varies from 14 to 22 min. The magnetic
field of the prominences was derived, which ranges from 14 to 20 G.
Title: Co-seismic rupture of the 2021, Mw7.4 Maduo
earthquake (northern Tibet): Short-cutting of the Kunlun fault
big bend
Authors: Pan, Jiawei; Li, Haibing; Chevalier, Marie-Luce; Tapponnier,
Paul; Bai, Mingkun; Li, Chao; Liu, Fucai; Liu, Dongliang; Wu, Kungang;
Wang, Ping; Li, Chunrui; Lu, Haijian; Chen, Peng
Bibcode: 2022E&PSL.59417703P
Altcode:
We report detailed field measurements of the 2021, Mw7.4
Maduo earthquake surface rupture south of the Kunlun fault, near
the northern boundary of Tibet's Bayan Har block. In the field, the
dominantly left-lateral surface rupture length was ∼151 km, along
the poorly known Jiangcuo fault, with maximum horizontal and vertical
displacements of ∼2.1±0.2 to 2.9±0.2 m (up to 3.6±0.2 m at one
site) and ∼1.2±0.2 to 1.8±0.2 m, respectively. The rupture, which
propagated bilaterally from a roughly central epicenter, terminated in
well-defined, ∼20 km-long horsetail splays, as predicted by Coulomb
stress failure, consistent with the very young age of the still
growing Jiangcuo fault, which may be trying to bypass the Anyemaqen
restraining bend in order to connect directly the Kokoxili and Maqen
segments of the main Kunlun fault. 14C dating at one site
(Cuoerjiala) implies long return times (≥6500 years) for M7+,
Maduo-type earthquakes, in keeping with a slow horizontal slip rate
of ∼0.55±0.03 mm/yr and the subdued geomorphic expression of the
fault. In the broader Tibetan tectonics framework, the Jiangcuo fault
may be better interpreted as a kinematic streamlining of the Kunlun
fault bend, rather than a result of diffuse deformation across the
Bayan Har terrane.
Title: Coronal loop kink oscillation periods derived from the
information of density, magnetic field, and loop geometry
Authors: Chen, G. Y.; Chen, L. Y.; Guo, Y.; Ding, M. D.; Chen, P. F.;
Erdélyi, R.
Bibcode: 2022A&A...664A..48C
Altcode:
Context. Coronal loop oscillations can be triggered by solar eruptions,
for example, and are observed frequently by the Atmospheric Imaging
Assembly (AIA) on board Solar Dynamics Observatory (SDO). The
Helioseismic and Magnetic Imager (HMI) on board SDO offers us the
opportunity to measure the photospheric vector magnetic field and
carry out solar magneto-seismology (SMS).
Aims: By applying SMS,
we aim to verify the consistency between the observed period and the
one derived from the information of coronal density, magnetic field,
and loop geometry, that is, the shape of the loop axis.
Methods:
We analysed the data of three coronal loop oscillation events detected
by SDO/AIA and SDO/HMI. First, we obtained oscillation parameters
by fitting the observational data. Second, we used a differential
emission measure (DEM) analysis to diagnose the temperature and
density distribution along the coronal loop. Subsequently, we applied
magnetic field extrapolation to reconstruct the three-dimensional
magnetic field and then, finally, used the shooting method to compute
the oscillation periods from the governing equation.
Results:
The average magnetic field determined by magnetic field extrapolation
is consistent with that derived by SMS. A new analytical solution is
found under the assumption of exponential density profile and uniform
magnetic field. The periods estimated by combining the coronal density
and magnetic field distribution and the associated loop geometry are
closest to the observed ones, and are more realistic than when the
loop geometry is regarded as being semi-circular or having a linear
shape.
Conclusions: The period of a coronal loop is sensitive
to not only the density and magnetic field distribution but also the
loop geometry.
Title: ZTF Transient Discovery Report for 2022-07-11
Authors: Sollerman, J.; Zimmerman, E.; Irani, I.; Chen, P.; Gal-Yam,
A.; Schulze, S.
Bibcode: 2022TNSTR1948....1S
Altcode:
No abstract at ADS
Title: Cross-Loop Propagation of a Quasi-Periodic Extreme-Ultraviolet
Wave Triggered by a Solar Eruption
Authors: Sun, Zheng; Chen, P. F.; Tian, Hui; Yao, Shuo; Hou, Zhenyong;
Chen, Hechao; Gao, Yuhang
Bibcode: 2022cosp...44.2499S
Altcode:
Extreme-ultraviolet (EUV) waves refer to large-scale disturbances
propagating outward from sites of solar eruptions in EUV narrow-band
imaging observations of the Sun. These waves are normally single pulses
propagating radially from the eruption sites. Using observations
from the Atmospheric Imaging Assembly (AIA) on board the Solar
Dynamics Observatory, we report a very rare case of EUV wave,
which is characterized by quasi-periodic propagation across coronal
loops. Excited by an M1.7-class solar flare occurring at NOAA active
region 12887 on 2 November 2021, the wave exhibits slow and fast
components. The slow component, whose average speed is about 103
km/s, appears to originate from the opening of coronal loops at one
footpoint. The fast component represents a relatively large disturbance,
propagating across the coronal loops at an average speed of about
308 km/s. There is no significant decrease in the speeds of both
components. A wavelet analysis reveals that the periods of the slow and
fast components are both ~132 s, which is close to the period of the
quasi-periodic pulsations (QPP) at the flare ribbon, ~158 s. We suggest
that the slow component is caused by successive opening and expansion
of coronal loops, and that the fast component represents fast-mode
magnetoacoustic wave trains triggered by the loop expansion. The
quasi-periodic loop opening is likely accompanied by an intermittent
energy release process that heats the flare ribbon quasi-periodically.
Title: ZTF Transient Classification Report for 2022-07-11
Authors: Zimmerman, E.; Irani, I.; Chen, P.; Bruch, R.; Gal-Yam, A.;
Sollerman, J.; Schulze, S.
Bibcode: 2022TNSCR1951....1Z
Altcode:
No abstract at ADS
Title: Decayless longitudinal oscillations of a solar filament
maintained by quasi-periodic jets
Authors: Ni, Y. W.; Guo, J. H.; Zhang, Q. M.; Chen, J. L.; Fang, C.;
Chen, P. F.
Bibcode: 2022A&A...663A..31N
Altcode: 2022arXiv220315660N
Context. As a ubiquitous phenomenon, large-amplitude longitudinal
filament oscillations usually decay in 1-4 periods. Recently, we
observed a decayless case of such oscillations in the corona.
Aims: We try to understand the physical process that maintains the
decayless oscillation of the filament.
Methods: Multiwavelength
imaging observations and magnetograms were collected to study the
dynamics of the filament oscillation and its associated phenomena. To
explain the decayless oscillations, we also performed one-dimensional
hydrodynamic numerical simulations using the code MPI-AMRVAC.
Results: In observations, the filament oscillates without decay with
a period of 36.4 ± 0.3 min for almost 4 h before eruption. During
oscillations, four quasi-periodic jets emanate from a magnetic
cancellation site near the filament. The time interval between
neighboring jets is ∼68.9 ± 1.0 min. Numerical simulations
constrained by the observations reproduced the decayless longitudinal
oscillations. However, it is surprising to find that the period
of the decayless oscillations is not consistent with the pendulum
model.
Conclusions: We propose that the decayless longitudinal
oscillations of the filament are maintained by quasi-periodic jets,
which is verified by the hydrodynamic simulations. More importantly,
it is found that, when it is driven by quasi-periodic jets, the
period of the filament longitudinal oscillations also depends
on the driving period of the jets, not on the pendulum period
alone. With a parameter survey in simulations, we derived a formula
by which the pendulum oscillation period can be derived using the
observed period of decayless filament oscillations and the driving
periods of jets. Movie associated to Fig. 2 is available at https://www.aanda.org
Title: ZTF early discovery and rapid follow-up of the infant type
I SN 2022oqm / ZTF22aasxgjp
Authors: Zimmerman, E.; Irani, I.; Bruch, R.; Chen, P.; Gal-Yam, A.;
Sollerman, J.; Schulze, S.; Perley, D.
Bibcode: 2022TNSAN.142....1Z
Altcode:
We report the ZTF discovery of SN 2022oqm / ZTF22aasxgjp - a
rapidly rising young type I supernova in the nearby galaxy NGC 5875,
z=0.0113. At a distance of ~50 Mpc the transient was discovered on
July 11, 2022 at 04:40 UT with an absolute ZTF g-band magnitude of M =
-16.2. We encourage follow-up observations of this transient.
Title: VizieR Online Data Catalog: CNIa0.02 project DR1: type Ia SN
z<0.02 light curves (Chen+, 2022)
Authors: Chen, P.; Dong, S.; Kochanek, C. S.; Stanek, K. Z.; Post,
R. S.; Stritzinger, M. D.; Prieto, J. L.; Filippenko, A. V.; Kollmeier,
J. A.; Elias-Rosa, N.; Katz, B.; Tomasella, L.; Bose, S.; Ashall,
C.; Benetti, S.; Bersier, D.; Brimacombe, J.; Brink, T. G.; Brown,
P.; Buckley, D. A. H.; Cappellaro, E.; Christie, G. W.; Fraser, M.;
Gromadzki, M.; Holoien, T. W. -S.; Hu, S.; Kankare, E.; Koff, R.;
Lundqvist, P.; Mattila, S.; Milne, P. A.; Morrell, N.; Munoz, J. A.;
Mutel, R.; Natusch, T.; Nicolas, J.; Pastorello, A.; Prentice, S.;
Roth, T.; Shappee, B. J.; Stone, G.; Thompson, T. A.; Villanueva,
S.; Zheng, W.
Bibcode: 2022yCat..22590053C
Altcode:
We select our targets primarily based on ASAS-SN detections, and
the complete sample was collected between 2015 September 17 and
2019 January 31. We have also observed a few SNe Ia before (since
2015 January) and after this period (until 2020 January), and they
are included in DR1, but are not part of the complete sample. CNIa0.02 DR1 includes V-band and g-band photometry from the 14cm
telescopes used to conduct the ASAS-SN survey. Immediately after
the discovery of an SN candidate that met our magnitude criteria,
we started multiband photometric observations. For most objects, this
data release contains follow-up photometry ending around 40-60days after
the optical peak. We have performed photometric follow-up observations
using a number of telescopes ranging from ~0.3m to ~2m (see Table 3;
Section 2 and Appendix B). (5 data files).
Title: Low-threshold ultrahigh-energy neutrino search with the
Askaryan Radio Array
Authors: Allison, P.; Archambault, S.; Beatty, J. J.; Besson,
D. Z.; Bishop, A.; Chen, C. C.; Chen, C. H.; Chen, P.; Chen, Y. C.;
Clark, B. A.; Clay, W.; Connolly, A.; Cremonesi, L.; Dasgupta, P.;
Davies, J.; de Kockere, S.; de Vries, K. D.; Deaconu, C.; DuVernois,
M. A.; Flaherty, J.; Friedman, E.; Gaior, R.; Hanson, J.; Harty, N.;
Hendricks, B.; Hoffman, K. D.; Hong, E.; Hsu, S. Y.; Hu, L.; Huang,
J. J.; Huang, M. -H.; Hughes, K.; Ishihara, A.; Karle, A.; Kelley,
J. L.; Kim, K. -C.; Kim, M. -C.; Kravchenko, I.; Krebs, R.; Ku, Y.;
Kuo, C. Y.; Kurusu, K.; Landsman, H.; Latif, U. A.; Li, C. -J.; Liu,
T. -C.; Lu, M. -Y.; Madison, B.; Madison, K.; Mase, K.; Meures, T.;
Nam, J.; Nichol, R. J.; Nir, G.; Novikov, A.; Nozdrina, A.; Oberla,
E.; Osborn, J.; Pan, Y.; Pfendner, C.; Punsuebsay, N.; Roth, J.;
Seckel, D.; Seikh, M. F. H.; Shiao, Y. -S.; Shultz, A.; Smith, D.;
Toscano, S.; Torres, J.; Touart, J.; van Eijndhoven, N.; Varner,
G. S.; Vieregg, A.; Wang, M. -Z.; Wang, S. -H.; Wang, Y. H.; Wissel,
S. A.; Xie, C.; Yoshida, S.; Young, R.; ARA Collaboration
Bibcode: 2022PhRvD.105l2006A
Altcode: 2022arXiv220207080A
In the pursuit of the measurement of the still-elusive ultrahigh-energy
(UHE) neutrino flux at energies of order EeV, detectors using
the in-ice Askaryan radio technique have increasingly targeted
lower trigger thresholds. This has led to improved trigger-level
sensitivity to UHE neutrinos. Working with data collected by the
Askaryan Radio Array (ARA), we search for neutrino candidates at the
lowest threshold achieved to date, leading to improved analysis-level
sensitivities. A neutrino search on a data set with 208.7 days of
livetime from the reduced-threshold fifth ARA station is performed,
achieving a 68% analysis efficiency over all energies on a simulated
mixed-composition neutrino flux with an expected background of
0.10-0.04+0.06 events passing the analysis. We
observe one event passing our analysis and proceed to set a neutrino
flux limit using a Feldman-Cousins construction. We show that the
improved trigger-level sensitivity can be carried through an analysis,
motivating the phased array triggering technique for use in future
radio-detection experiments. We also include a projection using
all available data from this detector. Finally, we find that future
analyses will benefit from studies of events near the surface to fully
understand the background expected for a large-scale detector.
Title: Mantle Wedge Water Contents Estimated From Ultrasonic
Laboratory Measurements of Olivine-Antigorite Aggregates
Authors: Wang, Duojun; Wang, Libing; Zhang, Rui; Cai, Nao; Zhang,
Jikai; Chen, Peng; Cao, Yang
Bibcode: 2022GeoRL..4998226W
Altcode:
While it is known that serpentinized peridotite acts as a water
reservoir in the mantle wedge of a subduction zone, the spatial
distribution and quantity of the water stored in these reservoirs,
as well as the acoustic velocity of the olivine-antigorite aggregates,
are not well constrained. Here, we report the propagation of seismic
waves through synthetic olivine-antigorite aggregates, which are used
as proxies for various mantle wedge lithologies, by varying the amount
of antigorite at pressures up to 8 GPa. Our results indicate that the
acoustic velocity is strongly dependent on the proportion of antigorite
in the sample and somewhat dependent on pressure. We empirically
explore the relationship between the acoustic velocity and the degree
of serpentinization as well as pressure to map the water content in
the mantle wedge. Our estimations show that the water content among the
subducting slabs around the Pacific Ocean is between 0.5 and 5.0 wt%.
Title: Avalanches of magnetic flux rope in the state of self-organized
criticality
Authors: Wang, W. B.; Li, C.; Tu, Z. L.; Guo, J. H.; Chen, P. F.;
Wang, F. Y.
Bibcode: 2022MNRAS.512.1567W
Altcode: 2022MNRAS.tmp..661W
The self-organized criticality (SOC) is a universal theory to
explain the ubiquitous power-law size distributions of astrophysical
instabilities such as solar eruptions. One way to understand the
dynamical processes of an SOC system is through cellular automaton
(CA) simulations. Here, we develop a three-dimensional solar CA
model that assumes a twisted magnetic flux rope (MFR), in which the
avalanche takes place when a local magnetic vector potential exceeds
a Gaussian distributed instability criterion, triggered by a global
and space-dependent energy driving mechanism. To avoid non-physical
released energies, an energy screening mechanism is applied to calculate
the avalanche energies of each time-step. Our results show that the
statistics of the CA simulated flaring events are comparable to the
frequency distributions of observed solar flares originating from an
individual active region. Due to the fact of the universality of MFRs,
the CA model can be applied to many other astrophysical SOC systems.
Title: ZTF Transient Classification Report for 2022-05-16
Authors: Bruch, R.; Sollerman, J.; Zimmerman, E.; Chen, P.; Irani,
I.; Gal-Yam, A.; Yaron, O.
Bibcode: 2022TNSCR1323....1B
Altcode:
No abstract at ADS
Title: ZTF early discovery and rapid follow-up of the infant SN
ZTF22aakdbia / 2022jzc
Authors: Bruch, R.; Sollerman, J.; Zimmerman, E.; Chen, P.; Irani,
I.; Schulze, S.; Gal-Yam, A.; Yaron, O.
Bibcode: 2022TNSAN.108....1B
Altcode:
We report the ZTF discovery of ZTF22aakdbia / 2022jzc - a young
supernova in a nearby galaxy (z=0.0029). At a distance of ~13 Mpc the
transient was discovered on May 16, 2022 at 04:54 UT with an absolute
ZTF g-band magnitude of M = -12.7 . We encourage follow-up observations
of this transient.
Title: Research on the ionospheric diurnal Double-Maxima patterns
in Asia-Australian area based on the VTEC observations of BDS
geostationary satellites
Authors: Wang, Rong; Chen, Peng; Yao, Yibin; An, Zhiyuan; Wang, Zhihao
Bibcode: 2022AdSpR..69.3705W
Altcode:
Ionospheric diurnal double-maxima (DDM) pattern is a special
phenomenon of the ionosphere, which shows that the ionospheric electron
density/total electron content (TEC) presents a two-peak structure
during the daytime. This paper uses the Beidou geostationary (GEO)
vertical total electron content (VTEC) data from the MGEX tracking
stations in the Asian-Australian area from 2019 to 2020 to study the
ionospheric DDM phenomenon. The results show that the occurrence
rate of ionospheric DDM is roughly symmetrical about the magnetic
equator, with a "W"-shaped distribution. With decreasing latitude,
the occurrence of DDM first decreases from 58%/73% to 7%/17% and then
increases in the equatorial region to 30%. Minimum occurrence occurs
near ± 20°. The occurrence rate of DDM in different latitude
regions varies with longitude. There is no significant variation at
low-latitudes (magnetic latitude 15°N ∼ 15°S), while in the
northern hemisphere mid-latitudes (regions north of magnetic latitude
15°N), the occurrence of DDM first decreases and then increases
with longitude in the area of observation. The southern hemisphere's
mid-latitudes (regions south of magnetic latitude 15°S) east of 90°E
show an increasing trend with longitude. The two peaks and one valley of
DDM mainly occur in 10:00-13:00 LT, 14:00-18:00 LT, and 12:00-15:00 LT,
respectively. As the latitude decreases, the occurrence time of the DDM
structures tends to be delayed, but there is no significant variation
with an increase in longitude. The DDM phenomenon in the southern
hemisphere usually occurs earlier than in the northern hemisphere. The
occurrence time of the DDM structures in different months shows an
inverted "U" shape in the mid-latitudes of the northern hemisphere
and a "U" shape in the mid-latitudes of the southern hemisphere. DDM
structures appear the latest in the local summer and the earliest in the
winter. There is no significant variation in the low-latitude regions.
Title: Close, bright, and boxy: the superluminous SN 2018hti
Authors: Fiore, A.; Benetti, S.; Nicholl, M.; Reguitti, A.;
Cappellaro, E.; Campana, S.; Bose, S.; Paraskeva, E.; Berger, E.;
Bravo, T. M.; Burke, J.; Cai, Y. -Z.; Chen, T. -W.; Chen, P.; Ciolfi,
R.; Dong, S.; Gomez, S.; Gromadzki, M.; Gutiérrez, C. P.; Hiramatsu,
D.; Hosseinzadeh, G.; Howell, D. A.; Jerkstrand, A.; Kankare, E.;
Kozyreva, A.; Maguire, K.; McCully, C.; Ochner, P.; Pellegrino, C.;
Pignata, G.; Post, R. S.; Elias-Rosa, N.; Shahbandeh, M.; Schuldt,
S.; Thomas, B. P.; Tomasella, L.; Vinkó, J.; Vogl, C.; Wheeler,
J. C.; Young, D. R.
Bibcode: 2022MNRAS.512.4484F
Altcode: 2022MNRAS.tmp..717F; 2021arXiv211107142F
SN 2018hti was a very nearby (z = 0.0614) superluminous supernova with
an exceedingly bright absolute magnitude of -21.7 mag in r band at
maximum. The densely sampled pre-maximum light curves of SN 2018hti
show a slow luminosity evolution and constrain the rise time to ~50
rest-frame d. We fitted synthetic light curves to the photometry to
infer the physical parameters of the explosion of SN 2018hti for both
the magnetar and the CSM-interaction scenarios. We conclude that one
of two mechanisms could be powering the luminosity of SN 2018hti;
interaction with ~10 M⊙ of circumstellar material or a
magnetar with a magnetic field of Bp~ 1.3 × 1013
G, and initial period of Pspin~ 1.8 ms. From the nebular
spectrum modelling we infer that SN 2018hti likely results from the
explosion of a ${\sim}40\, \mathrm{M}_\odot$ progenitor star.
Title: ZTF Transient Classification Report for 2022-04-14
Authors: Bruch, R.; Sollerman, J.; Schulze, S.; Chen, P.; Gal-Yam,
A.; Zimmerman, E.
Bibcode: 2022TNSCR.983....1B
Altcode:
No abstract at ADS
Title: Early discovery and rapid followup of SN 2022fuc (ZTF22aadpuwe)
Authors: Zimmerman, E.; Sollerman, J.; Schulze, S.; Ashall, C.;
Shappee, B.; Yang, Y.; Bruch, R.; Chen, P.; Gal-Yam, A.; Perley, D.
Bibcode: 2022TNSAN..84....1Z
Altcode:
We report the early discovery and rapid followup observations of the
nearby Type II supernova SN 2022fuc.
Title: Transient Classification Report for 2022-04-04
Authors: Zimmerman, E.; Sollerman, J.; Schulze, S.; Ashall, C.;
Shappee, B.; Yang, Y.; Bruch, R.; Chen, P.; Gal-Yam, A.; Perley, D.
Bibcode: 2022TNSCR.874....1Z
Altcode:
No abstract at ADS
Title: Measuring the polarization reconstruction resolution of the
ARIANNA neutrino detector with cosmic rays
Authors: Anker, A.; Baldi, P.; Barwick, S. W.; Beise, J.; Besson,
D. Z.; Bouma, S.; Cataldo, M.; Chen, P.; Gaswint, G.; Glaser, C.;
Hallgren, A.; Hallmann, S.; Hanson, J. C.; Klein, S. R.; Kleinfelder,
S. A.; Lahmann, R.; Liu, J.; Magnuson, M.; McAleer, S.; Meyers,
Z. S.; Nam, J.; Nelles, A.; Novikov, A.; Paul, M. P.; Persichilli,
C.; Plaisier, I.; Pyras, L.; Rice-Smith, R.; Tatar, J.; Wang, S. -H.;
Welling, C.; Zhao, L.; Arianna Collaboration
Bibcode: 2022JCAP...04..022A
Altcode: 2021arXiv211201501A
The ARIANNA detector is designed to detect neutrinos with energies
above 1017 eV. Due to the similarities in generated
radio signals, cosmic rays are often used as test beams for neutrino
detectors. Some ARIANNA detector stations are equipped with antennas
capable of detecting air showers. Since the radio emission properties
of air showers are well understood, and the polarization of the radio
signal can be predicted from the arrival direction, cosmic rays can
be used as a proxy to assess the reconstruction capabilities of
the ARIANNA neutrino detector. We report on dedicated efforts of
reconstructing the polarization of cosmic-ray radio pulses. After
correcting for difference in hardware, the two stations used in this
study showed similar performance in terms of event rate and agreed with
simulation. Subselecting high quality cosmic rays, the polarizations
of these cosmic rays were reconstructed with a resolution of 2.5°
(68% containment), which agrees with the expected value obtained
from simulation. A large fraction of this resolution originates
from uncertainties in the predicted polarization because of the
contribution of the subdominant Askaryan effect in addition to the
dominant geomagnetic emission. Subselecting events with a zenith angle
greater than 70° removes most influence of the Askaryan emission,
and, with limited statistics, we found the polarization uncertainty
is reduced to 1.3° (68% containment).
Title: Dynamics and Kinematics of the EUV Wave Event on 6 May 2019
Authors: Chandra, Ramesh; Chen, P. F.; Devi, Pooja; Joshi, Reetika;
Ni, Y. W.
Bibcode: 2022Galax..10...58C
Altcode: 2022arXiv220404936C
We present here the kinematics of the EUV wave associated with a
GOES M1.0-class solar flare, which originates in NOAA AR 12740. The
event is thoroughly observed with Atmospheric Imaging Assembly (AIA)
onboard Solar Dynamics Observatory (SDO) with high spatio-temporal
resolutions. This event displays many features of EUV waves, which are
very decisive for the understanding of the nature of EUV waves. These
features include: a fast-mode wave, a pseudo wave, a slow-mode wave
and stationary fronts, probably due to mode conversion. One fast-mode
wave also propagates towards the coronal hole situated close to the
north pole and the wave speed does not change when it encounters the
coronal hole. We intend to provide self-consistent interpretations
for all these different features.
Title: ZTF early discovery and rapid follow-up of the infant SN
2022hnt / ZTF22aafrjnw
Authors: Bruch, R.; Sollerman, J.; Schulze, S.; Chen, P.; Gal-Yam,
A.; Zimmerman, E.
Bibcode: 2022TNSAN..88....1B
Altcode:
We report the ZTF discovery of SN 2022hnt / ZTF22aafrjnw - a rapidly
rising young supernova in the nearby galaxy NGC 3759A , z=0.0192. At
a distance of ~84 Mpc the transient was discovered on April 14, 2022
at 07:03 UT with an absolute ZTF g-band magnitude of M = -16.6. We
encourage follow-up observations of this transient.
Title: Quantifying the Magnetic Structure of a Coronal Shock Producing
a Type II Radio Burst
Authors: Su, W.; Li, T. M.; Cheng, X.; Feng, L.; Zhang, P. J.; Chen,
P. F.; Ding, M. D.; Chen, L. J.; Guo, Y.; Wang, Y.; Li, D.; Zhang,
L. Y.
Bibcode: 2022ApJ...929..175S
Altcode: 2022arXiv220311042S
Type II radio bursts are thought to be produced by shock waves in the
solar atmosphere. However, what magnetic conditions are needed for the
generation of type II radio bursts is still a puzzling issue. Here,
we quantify the magnetic structure of a coronal shock associated with
a type II radio burst. Based on multiperspective extreme-ultraviolet
observations, we reconstruct the three-dimensional (3D) shock
surface. By using a magnetic field extrapolation model, we then derive
the orientation of the magnetic field relative to the normal of the
shock front (θ Bn) and the Alfvén Mach number (M
A ) on the shock front. Combining the radio observations from
the Nancay Radio Heliograph, we obtain the source region of the type
II radio burst on the shock front. It is found that the radio burst
is generated by a shock with M A ≳ 1.5 and a bimodal
distribution of θ Bn. We also use the Rankine-Hugoniot
relations to quantify the properties of the shock downstream. Our
results provide a quantitative 3D magnetic structure condition of a
coronal shock that produces a type II radio burst.
Title: yonder: A Python Package for Data Denoising and Reconstruction
Authors: Chen, Peng; De Souza, Rafael S.
Bibcode: 2022zndo...6321520C
Altcode:
Yonder: A Python package for noisy data reduction.
Title: Global tropospheric delay grid modeling based on Anti-Leakage
Least-Squares Spectral Analysis and its validation
Authors: Ma, Yongchao; Liu, Tong; Chen, Peng; Zheng, Naiquan; Zhang,
Bing; Xu, Guochang; Lu, Zhiping
Bibcode: 2022JASTP.22905829M
Altcode:
Tropospheric delay is one of the primary error sources of the Global
Navigation Satellite System (GNSS). Usually, a traditional empirical
model can be corrected, which uses the trigonometric function of fixed
amplitude and frequency for time fitting. However, the traditional
models only retain the low-frequency information of the zenith
tropospheric delay (ZTD), which limits its application in high time
resolution. To solve this problem, a global tropospheric delay grid
model, namely AGtrop, is developed based on Anti-Leakage Least-Squares
Spectral analysis. The results of the AGtrop model are evaluated by
three kinds of sources, including ERA5 data, IGS, and the sounding
profile of radiosonde station throughout the year 2019. Compared with
the traditional model GPT2w and UNB3m, AGtrop shows better performance,
especially in low latitudes and the southern hemisphere. AGtrop can
generally achieve a global mean Bias/RMSE of 0.35/2.34 cm in contrast
to ERA5 derived ZTD, 0.59/2.29 cm in comparison with IGS ZTD, and
0.18/3.71 cm in the match to Radiosonde derived ZTD. Besides, the
AGtrop model has an enhancement effect in localized areas. AGtrop
model is characterized by simplicity and accuracy, which will be of
great significance to real-time GNSS applications.
Title: TAROGE-M: Radio Observatory on Antarctic High Mountain for
Detecting Near-Horizon Ultra-High Energy Air Showers
Authors: Wang, S. H.; Chen, P.; Chen, Y.; Huang, J. J.; Huang,
M. H. A.; Kuo, C. Y.; Leung, C. H.; Liu, T. C.; Nam, J.; Shiao,
Y. S. J.; Wang, M. Z.; Wang, Y. H.; Anker, A.; Baldi, P.; Barwick,
S. W.; Beise, J.; Bernhoff, H.; Besson, D.; Bingefors, N.; Fernández,
D.; Gaswint, G.; Glaser, C.; Hallgren, A.; Hanson, J.; Klein, S.;
Kleinfelder, S. A.; Lahmann, R.; Liu, J.; Magnuson, M.; McAleer, S.;
Nelles, A.; Novikov, A.; Paul, M. P.; Persichilli, C.; Plaisier, I.;
Rice-Smith, R.; Tatar, J.; Welling, C.; Zhao, L.
Bibcode: 2022icrc.confE1173W
Altcode: 2022PoS...395E1173W
No abstract at ADS
Title: Discovering the Highest Energy Neutrinos with the Payload
for Ultrahigh Energy Observations (PUEO)
Authors: Vieregg, A. G.; Abarr, Q.; Allison, P.; Ammerman Yebra, J.;
Alvarez-Muñiz, J.; Beatty, J. J.; Besson, D. Z.; Chen, P.; Chen,
Y.; Cheng, X.; Clem, J. M.; Connolly, A.; Cremonesi, L.; Deaconu,
C.; Flaherty, J.; Frikken, D.; Gorham, P. W.; Hast, C.; Hornhuber,
C.; Huang, J. J.; Hughes, K.; Hynous, A.; Ku, Y.; Kuo, C. Y.; Liu,
T. C.; Martin, Z.; Miki, C.; Nam, J.; Nichol, R. J.; Nishimura,
K.; Novikov, A.; Nozdrina, A.; Oberla, E.; Prohira, S.; Prechelt,
R.; Rauch, B. F.; Roberts, J. M.; Romero-Wolf, A.; Russell, J. W.;
Seckel, D.; Shiao, J.; Smith, D. J. B.; Southall, D.; Varner, G. S.;
Wang, S. H.; Wang, Y. H.; Wissel, S. A.; Young, R.; Zas, E.; Zeolla, A.
Bibcode: 2022icrc.confE1029V
Altcode: 2022PoS...395E1029V
No abstract at ADS
Title: A neural network based UHE neutrino reconstruction method
for the Askaryan Radio Array (ARA)
Authors: Pan, Y.; Allison, P.; Archambault, S.; Beatty, J. J.;
Beheler-Amass, M.; Besson, D. Z.; Beydler, M.; Chen, C. H.; Chen,
P.; Chen, Y. C.; Clark, B. A.; Clay, W.; Connolly, A.; Cremonesi, L.;
Dasgupta, P.; Davies, J.; De Kockere, S.; de Vries, K. D.; Deaconu, C.;
DuVernois, M. A.; Flaherty, J.; Friedman, E.; Gaior, R.; Hanson, J. C.;
Hanson, K.; Harty, N.; Hendricks, B.; Hoffman, K. D.; Hokanson-Fasig,
B.; Hong, E.; Hsu, S. Y.; Huang, J. J.; Huang, M. H. A.; Hughes, K.;
Ishihara, A.; Karle, A.; Kelley, J. L.; Khandelwal, R.; Kim, K. C.;
Kim, M. C.; Krebs, R.; Kravchenko, I.; Ku, Y.; Kuo, C. Y.; Kurusu,
K.; Latif, U. A.; Laundrie, A.; Landsman, H.; Lu, M. Y.; Liu, T. C.;
Madison, B.; Mase, K.; Meures, T.; Nam, J.; Novikov, A.; Nichol,
R. J.; Nir, G.; Nozdrina, A.; Oberla, E.; ÓMurchadha, A.; Osborn,
J.; Pan, Y.; Pfendner, C.; Punsuebsay, N.; Roth, J.; Sandstrom, P.;
Seckel, D.; Shiao, Y. S.; Shultz, A.; Smith, D. J. B.; Torres, J.;
Toscano, S.; Touart, J.; van Eijndhoven, N.; Varner, G. S.; Vieregg,
A.; Wang, M. Z.; Wang, S. H.; Wang, Y. H.; Wissel, S. A.; Xie, C.;
Young, R. D.; Yoshida, S.
Bibcode: 2022icrc.confE1157P
Altcode: 2022PoS...395E1157P
No abstract at ADS
Title: A Template-based UHE Neutrino Search Strategy for the Askaryan
Radio Array (ARA)
Authors: Kim, M.; Allison, P.; Archambault, S.; Beatty, J. J.;
Beheler-Amass, M.; Besson, D. Z.; Beydler, M.; Chen, C. H.; Chen,
P.; Chen, Y. C.; Clark, B. A.; Clay, W.; Connolly, A.; Cremonesi, L.;
Dasgupta, P.; Davies, J.; De Kockere, S.; de Vries, K. D.; Deaconu, C.;
DuVernois, M. A.; Flaherty, J.; Friedman, E.; Gaior, R.; Hanson, J. C.;
Hanson, K.; Harty, N.; Hendricks, B.; Hoffman, K. D.; Hokanson-Fasig,
B.; Hong, E.; Hsu, S. Y.; Huang, J. J.; Huang, M. H. A.; Hughes, K.;
Ishihara, A.; Karle, A.; Kelley, J. L.; Khandelwal, R.; Kim, K. C.;
Krebs, R.; Kravchenko, I.; Ku, Y.; Kuo, C. Y.; Kurusu, K.; Latif,
U. A.; Laundrie, A.; Landsman, H.; Lu, M. Y.; Liu, T. C.; Madison,
B.; Mase, K.; Meures, T.; Nam, J.; Novikov, A.; Nichol, R. J.; Nir,
G.; Nozdrina, A.; Oberla, E.; ÓMurchadha, A.; Osborn, J.; Pan, Y.;
Pfendner, C.; Punsuebsay, N.; Roth, J.; Sandstrom, P.; Seckel, D.;
Shiao, Y. S.; Shultz, A.; Smith, D. J. B.; Torres, J.; Toscano, S.;
Touart, J.; van Eijndhoven, N.; Varner, G. S.; Vieregg, A.; Wang,
M. Z.; Wang, S. H.; Wang, Y. H.; Wissel, S. A.; Xie, C.; Young, R. D.;
Yoshida, S.
Bibcode: 2022icrc.confE1147K
Altcode: 2022PoS...395E1147K
No abstract at ADS
Title: Development of drone-borne aerial calibration pulser system
for radio observatories of ultra-high energy air showers
Authors: Kuo, C. Y.; Nam, J.; Shin, B.; Chen, P.; Chen, Y.; Hsu, S. Y.;
Huang, J. J.; Huang, M. H. A.; Leung, C. H.; Liu, T. C.; Wang, S. H.;
Wang, M. Z.; Wang, Y. H.; Besson, D. Z.; Novikov, A.; Hornhuber, C.;
Young, R.
Bibcode: 2022icrc.confE.283K
Altcode: 2022PoS...395E.283K
No abstract at ADS
Title: Implementing a Low-Threshold Analysis with the Askaryan Radio
Array (ARA)
Authors: Hughes, K.; Allison, P.; Archambault, S.; Beatty, J. J.;
Beheler-Amass, M.; Besson, D. Z.; Beydler, M.; Chen, C. H.; Chen,
P.; Chen, Y. C.; Clark, B. A.; Clay, W.; Connolly, A.; Cremonesi, L.;
Dasgupta, P.; Davies, J.; De Kockere, S.; de Vries, K. D.; Deaconu, C.;
DuVernois, M. A.; Flaherty, J.; Friedman, E.; Gaior, R.; Hanson, J. C.;
Hanson, K.; Harty, N.; Hendricks, B.; Hoffman, K. D.; Hokanson-Fasig,
B.; Hong, E.; Hsu, S. Y.; Huang, J. J.; Huang, M. H. A.; Hughes, K.;
Ishihara, A.; Karle, A.; Kelley, J. L.; Khandelwal, R.; Kim, K. C.;
Kim, M. C.; Krebs, R.; Kravchenko, I.; Ku, Y.; Kuo, C. Y.; Kurusu,
K.; Latif, U. A.; Laundrie, A.; Landsman, H.; Lu, M. Y.; Liu, T. C.;
Madison, B.; Mase, K.; Meures, T.; Nam, J.; Novikov, A.; Nichol,
R. J.; Nir, G.; Nozdrina, A.; Oberla, E.; ÓMurchadha, A.; Osborn,
J.; Pan, Y.; Pfendner, C.; Punsuebsay, N.; Roth, J.; Sandstrom, P.;
Seckel, D.; Shiao, Y. S.; Shultz, A.; Smith, D. J. B.; Torres, J.;
Toscano, S.; Touart, J.; van Eijndhoven, N.; Varner, G. S.; Vieregg,
A.; Wang, M. Z.; Wang, S. H.; Wang, Y. H.; Wissel, S. A.; Xie, C.;
Young, R. D.; Yoshida, S.
Bibcode: 2022icrc.confE1153H
Altcode: 2022PoS...395E1153H
No abstract at ADS
Title: The Calibration of the Geometry and Antenna Delay in Askaryan
Radio Array Station 4 and 5
Authors: Dasgupta, P.; Hughes, K.; Beheler-Amass, M.; Dasgupta, P.;
Huang, M. H. A.; Allison, P.; Archambault, S.; Beatty, J. J.; Besson,
D. Z.; Beydler, M.; Chen, C. H.; Chen, P.; Chen, Y. C.; Clark, B. A.;
Clay, W.; Connolly, A.; Cremonesi, L.; Davies, J.; de Vries, K. D.;
Deaconu, C.; Flaherty, J.; Friedman, E.; Gaior, R.; Hanson, K.; Harty,
N.; Hendricks, B.; Hoffman, K. D.; Hokanson-Fasig, B.; Hong, E.; Hsu,
S. Y.; Huang, J. J.; Huang, M. H.; Hughes, K.; Ishihara, A.; Karle,
A.; Kelley, J. L.; Khandelwal, R.; Kim, K. C.; Kim, M. C.; Krebs,
R.; Kravchenko, I.; Ku, Y.; Kuo, C. Y.; Kurusu, K.; Latif, U. A.;
Laundrie, A.; Landsman, H.; Lu, M. Y.; Liu, T. C.; Madison, B.; Mase,
K.; Meures, T.; Nam, J.; Novikov, A.; Nichol, R. J.; Nir, G.; Nozdrina,
A.; Oberla, E.; ÓMurchadha, A.; Osborn, J.; Pan, Y.; Pfendner, C.;
Punsuebsay, N.; Roth, J.; Sandstrom, P.; Seckel, D.; Shiao, Y. S.;
Shultz, A.; Smith, D. J. B.; Torres, J.; Toscano, S.; Touart, J.;
van Eijndhoven, N.; Varner, G. S.; Vieregg, A.; Wang, M. Z.; Wang,
S. H.; Wang, Y. H.; Wissel, S. A.; Xie, C.; Young, R. D.; Yoshida,
S.; Amass, M. B.; Kockere, S. D.; DuVernois, M. A.; Hanson, J. C.
Bibcode: 2022icrc.confE1086D
Altcode: 2022PoS...395E1086D
No abstract at ADS
Title: A novel trigger based on neural networks for radio neutrino
detectors
Authors: Arianna; Anker, A.; Baldi, P.; Barwick, S. W.; Beise, J.;
Bernhoff, H.; Besson, D. Z.; Bingefors, N.; Cataldo, M.; Chen,
P.; García Fernández, D.; Gaswint, G.; Glaser, C.; Hallgren, A.;
Hallmann, S.; Hanson, J. C.; Klein, S. R.; Kleinfelder, S. A.; Lahmann,
R.; Liu, J.; Magnuson, M.; McAleer, S.; Meyers, Z.; Nam, J.; Nelles,
A.; Novikov, A.; Paul, M. P.; Persichilli, C.; Plaisier, I.; Pyras,
L.; Rice-Smith, R.; Tatar, J.; Wang, S. H.; Welling, C.; Zhao, L.
Bibcode: 2022icrc.confE1074A
Altcode: 2022PoS...395E1074A
No abstract at ADS
Title: SLAC T-510 experiment for radio emission from particle showers:
Detailed simulation study and interpretation
Authors: Bechtol, K.; Belov, K.; Borch, K.; Chen, P.; Clem, J.;
Gorham, P.; Hast, C.; Huege, T.; Hyneman, R.; Jobe, K.; Kuwatani, K.;
Lam, J.; Liu, T. C.; Mulrey, K.; Nam, J.; Naudet, C.; Nichol, R. J.;
Paciaroni, C.; Rauch, B. F.; Romero-Wolf, A.; Rotter, B.; Saltzberg,
D.; Schoorlemmer, H.; Seckel, D.; Strutt, B.; Vieregg, A.; Williams,
C.; Wissel, S.; Zilles, A.
Bibcode: 2022PhRvD.105f3025B
Altcode: 2021arXiv211104334B
Over the last several decades, radio detection of air showers has been
widely used to detect ultrahigh-energy cosmic rays. We developed an
experiment under controlled laboratory conditions at SLAC with which we
measured the radio-frequency radiation from a charged particle shower
produced by bunches of electrons as primaries with known energy. The
shower took place in a target made of high density polyethylene located
in a strong magnetic field. The experiment was designed so that Askaryan
and magnetically-induced components of the radio emission could be
measured independently. At the same time, we performed a detailed
simulation of this experiment to predict the radio signal using two
microscopic formalisms, endpoint and ZHS. In this paper, we present
the simulation scheme and make a comparison with data characteristics
such as linearity with magnetic field and amplitude. The simulations
agree with the measurements within uncertainties and present a
good description of the data. In particular, reflections within the
target that accounted for the largest systematic uncertainties are
addressed. The prediction of the amplitude of Askaryan emission agrees
with measurements to within 5% for the endpoint formalism and 11%
for the ZHS formalism. The amplitudes of magnetically-induced emission
agree to within 5% for the endpoint formalism and less than 1% for the
ZHS formalism. The agreement of the absolute scale of emission gives
confidence in state-of-the-art air shower simulations which are based
on the applied formalisms.
Title: Improving sensitivity of the ARIANNA detector by rejecting
thermal noise with deep learning
Authors: Anker, A.; Baldi, P.; Barwick, S. W.; Beise, J.; Besson,
D. Z.; Bouma, S.; Cataldo, M.; Chen, P.; Gaswint, G.; Glaser, C.;
Hallgren, A.; Hallmann, S.; Hanson, J. C.; Klein, S. R.; Kleinfelder,
S. A.; Lahmann, R.; Liu, J.; Magnuson, M.; McAleer, S.; Meyers,
Z. S.; Nam, J.; Nelles, A.; Novikov, A.; Paul, M. P.; Persichilli,
C.; Plaisier, I.; Pyras, L.; Rice-Smith, R.; Tatar, J.; Wang, S. -H.;
Welling, C.; Zhao, L.; Arianna Collaboration
Bibcode: 2022JInst..17P3007A
Altcode: 2021arXiv211201031A
The ARIANNA experiment is an Askaryan detector designed to record
radio signals induced by neutrino interactions in the Antarctic
ice. Because of the low neutrino flux at high energies (E_ν> 10^16
eV), the physics output is limited by statistics. Hence, an increase
in sensitivity significantly improves the interpretation of data and
offers the ability to probe new parameter spaces. The amplitudes of the
trigger threshold are limited by the rate of triggering on unavoidable
thermal noise fluctuations. We present a real-time thermal noise
rejection algorithm that enables the trigger thresholds to be lowered,
which increases the sensitivity to neutrinos by up to a factor of two
(depending on energy) compared to the current ARIANNA capabilities. A
deep learning discriminator, based on a Convolutional Neural Network
(CNN), is implemented to identify and remove thermal events in real
time. We describe a CNN trained on MC data that runs on the current
ARIANNA microcomputer and retains 95% of the neutrino signal at a
thermal noise rejection factor of 10^5, compared to a template matching
procedure which reaches only 10^2 for the same signal efficiency. Then
the results are verified in a lab measurement by feeding in generated
neutrino-like signal pulses and thermal noise directly into the ARIANNA
data acquisition system. Lastly, the same CNN is used to classify
cosmic-rays events to make sure they are not rejected. The network
classified 102 out of 104 cosmic-ray events as signal.
Title: Capabilities of ARIANNA: Neutrino Pointing Resolution and
Implications for Future Ultra-high Energy Neutrino Astronomy
Authors: Barwick, S.; G., G.; Arianna Collaboration; Anker, A.;
Baldi, P.; Barwick, S. W.; Beise, J.; Bernhoff, H.; Besson, D. Z.;
Bingefors, N.; Cataldo, M.; Chen, P.; García Fernández, D.; Gaswint,
G.; Glaser, C.; Hallgren, A.; Hallmann, S.; Hanson, J. C.; Klein,
S. R.; Kleinfelder, S. A.; Lahmann, R.; Liu, J.; Magnuson, M.;
McAleer, S.; Meyers, Z.; Nam, J.; Nelles, A.; Novikov, A.; Paul,
M. P.; Persichilli, C.; Plaisier, I.; Pyras, L.; Rice-Smith, R.;
Tatar, J.; Wang, S. H.; Welling, C.; Zhao, L.
Bibcode: 2022icrc.confE1151B
Altcode: 2022PoS...395E1151B
No abstract at ADS
Title: Polarization Reconstruction of Cosmic Rays with the ARIANNA
Neutrino Radio Detector
Authors: Zhao, L.; Arianna; Anker, A.; Baldi, P.; Barwick, S. W.;
Beise, J.; Bernhoff, H.; Besson, D. Z.; Bingefors, N.; Cataldo, M.;
Chen, P.; García Fernández, D.; Gaswint, G.; Glaser, C.; Hallgren,
A.; Hallmann, S.; Hanson, J. C.; Klein, S. R.; Kleinfelder, S. A.;
Lahmann, R.; Liu, J.; Magnuson, M.; McAleer, S.; Meyers, Z.; Nam, J.;
Nelles, A.; Novikov, A.; Paul, M. P.; Persichilli, C.; Plaisier, I.;
Pyras, L.; Rice-Smith, R.; Tatar, J.; Wang, S. H.; Welling, C.
Bibcode: 2022icrc.confE1156Z
Altcode: 2022PoS...395E1156Z
No abstract at ADS
Title: Development of an in-situ calibration device of firn properties
for Askaryan neutrino detectors
Authors: Beise, J.; Glaser, C.; Arianna; Anker, A.; Baldi, P.; Barwick,
S. W.; Bernhoff, H.; Besson, D. Z.; Bingefors, N.; Cataldo, M.; Chen,
P.; García Fernández, D.; Gaswint, G.; Hallgren, A.; Hallmann,
S.; Hanson, J. C.; Klein, S. R.; Kleinfelder, S. A.; Lahmann, R.;
Liu, J.; Magnuson, M.; McAleer, S.; Meyers, Z.; Nam, J.; Nelles, A.;
Novikov, A.; Paul, M. P.; Persichilli, C.; Plaisier, I.; Pyras, L.;
Rice-Smith, R.; Tatar, J.; Wang, S. H.; Welling, C.; Zhao, L.
Bibcode: 2022icrc.confE1069B
Altcode: 2022PoS...395E1069B
No abstract at ADS
Title: JUNO Physics Prospects
Authors: Athayde Marcondes de André, J. P.; JUNO Collaboration;
Abusleme, A.; Adam, T.; Ahmad, S.; Ahmed, R.; Aiello, S.; Akram, M.;
An, F.; An, Q.; Andronico, G.; Anfimov, N.; Antonelli, V.; Antoshkina,
T.; Asavapibhop, B.; Auguste, D.; Babic, A.; Balashov, N.; Baldini,
W.; Barresi, A.; Basilico, D.; Baussan, E.; Bellato, M.; Bergnoli,
A.; Birkenfeld, T.; Blin, S.; Blum, D.; Blyth, S.; Bolshakova, A.;
Bongrand, M.; Bordereau, C.; Breton, D.; Brigatti, A.; Brugnera, R.;
Bruno, R.; Budano, A.; Buscemi, M.; Busto, J.; Butorov, I.; Cabrera,
A.; Cai, H.; Cai, X.; Cai, Y.; Cai, Z.; Callegari, R.; Cammi, A.;
Campeny, A.; Cao, C.; Cao, G.; Cao, J.; Caruso, R.; Cerna, C.;
Chang, J.; Chang, Y.; Chen, P.; Chen, P. A.; Chen, S.; Chen, X.;
Chen, Y. W.; Chen, Y.; Chen, Y.; Chen, Z.; Cheng, J.; Cheng, Y.;
Chetverikov, A.; Chiesa, D.; Chimenti, P.; Chukanov, A.; Claverie,
G.; Clementi, C.; Clerbaux, B.; Conforti Di Lorenzo, S.; Corti, D.;
Dal Corso, F.; Dalager, O.; De La Taille, C.; Deng, J.; Deng, Z.;
Deng, Z.; Depnering, W.; Diaz, M.; Ding, X.; Ding, Y.; Dirgantara,
B.; Dmitrievsky, S.; Dohnal, T.; Dolzhikov, D.; Donchenko, G.; Dong,
J.; Doroshkevich, E.; Dracos, M.; Druillole, F.; Du, R.; Du, S.;
Dusini, S.; Dvorak, M.; Enqvist, T.; Enzmann, H.; Fabbri, A.; Fajt,
L.; Fan, D.; Fan, L.; Fang, J.; Fang, W.; Fargetta, M.; Fedoseev,
D.; Fekete, V.; Feng, L. C.; Feng, Q.; Ford, R.; Fournier, A.; Gan,
H.; Gao, F.; Garfagnini, A.; Gavrikov, A.; Giammarchi, M.; Giaz,
A.; Giudice, N.; Gonchar, M.; Gong, G.; Gong, H.; Gornushkin, Y.;
Göttel, A. S.; Grassi, M.; Grewing, C.; Gromov, V.; Gu, M.; Gu, X.;
Gu, Y.; Guan, M.; Guardone, N.; Gul, M.; Guo, C.; Guo, J.; Guo, W.;
Guo, X.; Guo, Y.; Hackspacher, P.; Hagner, C.; Han, R.; Han, Y.;
Hassan, M. S.; He, M.; He, W.; Heinz, T.; Hellmuth, P.; Heng, Y.;
Herrera, R.; Hor, Y.; Hou, S.; Hsiung, Y. B.; Hu, B. Z.; Hu, H.; Hu,
J.; Hu, J.; Hu, S.; Hu, T.; Hu, Z.; Huang, C.; Huang, G.; Huang, H.;
Huang, W.; Huang, X.; Huang, X.; Huang, Y.; Hui, J.; Huo, L.; Huo,
W.; Huss, C.; Hussain, S.; Ioannisian, A.; Isocrate, R.; Jelmini,
B.; Jen, K. L.; Jeria, I.; Ji, X.; Ji, X.; Jia, H.; Jia, J.; Jian,
S.; Jiang, D.; Jiang, W.; Jiang, X.; Jin, R.; Jing, X.; Jollet, C.;
Joutsenvaara, J.; Jungthawan, S.; Kalousis, L.; Kampmann, P.; Kang,
L.; Karaparambil, R.; Kazarian, N.; Khosonthongkee, K.; Korablev, D.;
Kouzakov, K.; Krasnoperov, A.; Kruth, A.; Kutovskiy, N.; Kuusiniemi,
P.; Lachenmaier, T.; Landini, C.; Leblanc, S.; Lebrin, V.; Lefevre,
F.; Lei, R.; Leitner, R.; Leung, J.; Li, D.; Li, F.; Li, F.; Li, H.;
Li, H.; Li, J.; Li, M.; Li, M.; Li, N.; Li, Q.; Li, R.; Li, S.; Li, T.;
Li, W.; Li, W.; Li, X.; Li, X.; Li, X.; Li, Y.; Li, Y.; Li, Z.; Li, Z.;
Li, Z.; Liang, H.; Liao, J.; Liebau, D.; Limphirat, A.; Limpijumnong,
S.; Lin, G. L.; Lin, S.; Lin, T.; Ling, J.; Lippi, I.; Liu, F.; Liu,
H.; Liu, H.; Liu, H.; Liu, H.; Liu, H.; Liu, J.; Liu, J.; Liu, M.;
Liu, Q.; Liu, Q.; Liu, R.; Liu, S.; Liu, S.; Liu, S.; Liu, X.; Liu,
X.; Liu, Y.; Liu, Y.; Lokhov, A.; Lombardi, P.; Lombardo, C.; Loo,
K.; Lu, C.; Lu, H.; Lu, J.; Lu, J.; Lu, S.; Lu, X.; Lubsandorzhiev,
B.; Lubsandorzhiev, S.; Ludhova, L.; Lukanov, A.; Luo, F.; Luo, G.;
Luo, P.; Luo, S.; Luo, W.; Lyashuk, V.; Ma, B.; Ma, Q.; Ma, S.; Ma,
X.; Ma, X.; Maalmi, J.; Malyshkin, Y.; Mandujano, R. C.; Mantovani,
F.; Manzali, F.; Mao, X.; Mao, Y.; Mari, S. M.; Marini, F.; Marium,
S.; Martellini, C.; Martin-Chassard, G.; Martini, A.; Mayer, M.;
Mayilyan, D.; Mednieks, I.; Meng, Y.; Meregaglia, A.; Meroni, E.;
Meyhöfer, D.; Mezzetto, M.; Miller, J.; Miramonti, L.; Montini, P.;
Montuschi, M.; Müller, A.; Nastasi, M.; Naumov, D. V.; Naumova, E.;
Navas Nicolas, D.; Nemchenok, I.; Nguyen Thi, M. T.; Ning, F.; Ning,
Z.; Nunokawa, H.; Oberauer, L.; Ochoa-Ricoux, J. P.; Olshevskiy, A.;
Orestano, D.; Ortica, F.; Othegraven, R.; Pan, H. R.; Paoloni, A.;
Parmeggiano, S.; Pei, Y.; Pelliccia, N.; Peng, A.; Peng, H.; Perrot,
F.; Petitjean, P. A.; Petrucci, F.; Pilarczyk, O.; Piñeres Rico,
L. F.; Popov, A.; Poussot, P.; Pratumwan, W.; Previtali, E.; Qi, F.;
Qi, M.; Qian, S.; Qian, X.; Qian, Z.; Qiao, H.; Qin, Z.; Qiu, S.;
Rajput, M. U.; Ranucci, G.; Raper, N.; Re, A.; Rebber, H.; Rebii,
A.; Ren, B.; Ren, J.; Ricci, B.; Robens, M.; Roche, M.; Rodphai, N.;
Romani, A.; Roskovec, B.; Roth, C.; Ruan, X.; Ruan, X.; Rujirawat,
S.; Rybnikov, A.; Sadovsky, A.; Saggese, P.; Sanfilippo, S.; Sangka,
A.; Sanguansak, N.; Sawangwit, U.; Sawatzki, J.; Sawy, F.; Schever,
M.; Schwab, C.; Schweizer, K.; Selyunin, A.; Serafini, A.; Settanta,
G.; Settimo, M.; Shao, Z.; Sharov, V.; Shaydurova, A.; Shi, J.; Shi,
Y.; Shutov, V.; Sidorenkov, A.; Šimkovic, F.; Sirignano, C.; Siripak,
J.; Sisti, M.; Slupecki, M.; Smirnov, M.; Smirnov, O.; Sogo-Bezerra,
T.; Sokolov, S.; Songwadhana, J.; Soonthornthum, B.; Sotnikov, A.;
Šrámek, O.; Sreethawong, W.; Stahl, A.; Stanco, L.; Stankevich,
K.; Štefánik, D.; Steiger, H.; Steinmann, J.; Sterr, T.; Stock,
M. R.; Strati, V.; Studenikin, A.; Sun, S.; Sun, X.; Sun, Y.; Sun, Y.;
Suwonjandee, N.; Szelezniak, M.; Tang, J.; Tang, Q.; Tang, Q.; Tang,
X.; Tietzsch, A.; Tkachev, I.; Tměj, T.; Torri, M. D. C.; Treskov,
K.; Triossi, A.; Troni, G.; Trzaska, W. H.; Tuve, C.; Ushakov, N.;
van den Boom, J.; van Waasen, S.; Vanroyen, G.; Vedin, V.; Verde,
G.; Vialkov, M.; Viaud, B.; Vollbrecht, M.; Volpe, C.; Vorobel, V.;
Voronin, D.; Votano, L.; Walker, P.; Wang, C.; Wang, C. H.; Wang, E.;
Wang, G.; Wang, J.; Wang, J.; Wang, K.; Wang, L.; Wang, M.; Wang, M.;
Wang, R.; Wang, S.; Wang, W.; Wang, W.; Wang, X.; Wang, X.; Wang, Y.;
Wang, Y.; Wang, Y.; Wang, Y.; Wang, Y.; Wang, Y.; Wang, Z.; Wang, Z.;
Wang, Z.; Wang, Z.; Waqas, M.; Watcharangkool, A.; Wei, L.; Wei, W.;
Wei, W.; Wei, Y.; Wen, K.; Wen, L.; Wiebusch, C.; Wong, S. C. F.;
Wonsak, B.; Wu, D.; Wu, Q.; Wu, Z.; Wurm, M.; Wurtz, J.; Wysotzki,
C.; Xi, Y.; Xia, D.; Xie, X.; Xie, Y.; Xie, Z.; Xing, Z.; Xu, B. D.;
Xu, C.; Xu, D.; Xu, F.; Xu, H.; Xu, J.; Xu, J.; Xu, M.; Xu, Y.; Xu,
Y.; Yan, B.; Yan, T.; Yan, W.; Yan, X.; Yan, Y.; Yang, A.; Yang, C.;
Yang, C.; Yang, H.; Yang, J.; Yang, L.; Yang, X.; Yang, Y.; Yao, H.;
Yasin, Z.; Ye, J.; Ye, M.; Ye, Z.; Yegin, U.; Yermia, F.; Yi, P.;
Yin, N.; Yin, X.; You, Z.; Yu, B.; Yu, C.; Yu, C.; Yu, H.; Yu, M.;
Yu, X.; Yu, Z.; Yu, Z.; Yuan, C.; Yuan, Y.; Yuan, Z.; Yuan, Z.; Yue,
B.; Zafar, N.; Zambanini, A.; Zavadskyi, V.; Zeng, S.; Zeng, T.; Zeng,
Y.; Zhan, L.; Zhang, A.; Zhang, F.; Zhang, G.; Zhang, H.; Zhang, H.;
Zhang, J.; Zhang, J.; Zhang, J.; Zhang, J.; Zhang, J.; Zhang, P.;
Zhang, Q.; Zhang, S.; Zhang, S.; Zhang, T.; Zhang, X.; Zhang, X.;
Zhang, X.; Zhang, Y.; Zhang, Y.; Zhang, Y.; Zhang, Y.; Zhang, Y.;
Zhang, Y.; Zhang, Z.; Zhang, Z.; Zhao, F.; Zhao, J.; Zhao, R.; Zhao,
S.; Zhao, T.; Zheng, D.; Zheng, H.; Zheng, M.; Zheng, Y.; Zhong, W.;
Zhou, J.; Zhou, L.; Zhou, N.; Zhou, S.; Zhou, T.; Zhou, X.; Zhu, J.;
Zhu, K.; Zhu, K.; Zhu, Z.; Zhuang, B.; Zhuang, H.; Zong, L.; Zou, J.
Bibcode: 2022icrc.confE1194A
Altcode: 2022PoS...395E1194A
No abstract at ADS
Title: Science case and detector concept for ARIANNA high energy
neutrino telescope at Moore's Bay, Antarctica
Authors: Barwick, S.; Arianna; Anker, A.; Baldi, P.; Barwick, S. W.;
Beise, J.; Bernhoff, H.; Besson, D. Z.; Bingefors, N.; Cataldo, M.;
Chen, P.; García Fernández, D.; Gaswint, G.; Glaser, C.; Hallgren,
A.; Hallmann, S.; Hanson, J. C.; Klein, S. R.; Kleinfelder, S. A.;
Lahmann, R.; Liu, J.; Magnuson, M.; McAleer, S.; Meyers, Z.; Nam,
J.; Nelles, A.; Novikov, A.; Paul, M. P.; Persichilli, C.; Plaisier,
I.; Pyras, L.; Rice-Smith, R.; Tatar, J.; Wang, S. H.; Welling, C.;
Zhao, L.
Bibcode: 2022icrc.confE1190B
Altcode: 2022PoS...395E1190B
No abstract at ADS
Title: Yonder: A Python Package for Data Denoising and Reconstruction
Authors: Chen, Peng; de Souza, Rafael S.
Bibcode: 2022RNAAS...6...51C
Altcode: 2022arXiv220308071C
We present a standalone implementation of a data-deconvolution method
based on singular value decomposition. The tool is written in python
and packaged in the open-source yonder package. yonder receives as
input two matrices, one for the data and another for the errors, and
outputs a denoised version of the original dataset. In this Research
Note, we briefly describe the methodology and show a demonstration of
the yonder on a simulated dataset.
Title: PaulChern/LINVARIANT: v1.0
Authors: Chen, Peng
Bibcode: 2022zndo...5951858C
Altcode:
No description provided.
Title: Analysis of a tau neutrino origin for the near-horizon air
shower events observed by the fourth flight of the Antarctic Impulsive
Transient Antenna
Authors: Prechelt, R.; Wissel, S. A.; Romero-Wolf, A.; Burch, C.;
Gorham, P. W.; Allison, P.; Alvarez-Muñiz, J.; Banerjee, O.; Batten,
L.; Beatty, J. J.; Belov, K.; Besson, D. Z.; Binns, W. R.; Bugaev, V.;
Cao, P.; Carvalho, W.; Chen, C. H.; Chen, P.; Chen, Y.; Clem, J. M.;
Connolly, A.; Cremonesi, L.; Dailey, B.; Deaconu, C.; Dowkontt, P. F.;
Fox, B. D.; Gordon, J. W. H.; Hast, C.; Hill, B.; Hsu, S. Y.; Huang,
J. J.; Hughes, K.; Hupe, R.; Israel, M. H.; Liewer, K. M.; Liu, T. C.;
Ludwig, A. B.; Macchiarulo, L.; Matsuno, S.; McBride, K.; Miki, C.;
Mulrey, K.; Nam, J.; Naudet, C.; Nichol, R. J.; Novikov, A.; Oberla,
E.; Prohira, S.; Rauch, B. F.; Ripa, J.; Roberts, J. M.; Rotter, B.;
Russell, J. W.; Saltzberg, D.; Seckel, D.; Schoorlemmer, H.; Shiao,
J.; Stafford, S.; Stockham, J.; Stockham, M.; Strutt, B.; Sutherland,
M. S.; Varner, G. S.; Vieregg, A. G.; Wang, N.; Wang, S. H.; Zas,
E.; Zeolla, A.; Anita Collaboration
Bibcode: 2022PhRvD.105d2001P
Altcode: 2021arXiv211207069P
We study in detail the sensitivity of the Antarctic Impulsive Transient
Antenna (ANITA) to possible ντ point source fluxes detected
via τ -lepton-induced air showers. This investigation is framed around
the observation of four upward-going extensive air shower events very
close to the horizon seen in ANITA-IV. We find that these four upgoing
events are not observationally inconsistent with τ -induced EASs from
Earth-skimming ντ both in their spectral properties as
well as in their observed locations on the sky. These four events as
well as the overall diffuse and point source exposure to Earth-skimming
ντ are also compared against published ultrahigh-energy
neutrino limits from the Pierre Auger Observatory. While none of these
four events occurred at sky locations simultaneously visible by Auger,
the implied fluence necessary for ANITA to observe these events is
in strong tension with limits set by Auger across a wide range of
energies and is additionally in tension with ANITA's Askaryan in-ice
neutrino channel above 1019 eV . We conclude by discussing
some of the technical challenges with simulating and analyzing these
near horizon events and the potential for future observatories to
observe similar events.
Title: Development and Assessment of an ALLSSA-Based Atmospheric
Weighted Mean Temperature Model With High Time Resolution for GNSS
Precipitable Water Retrieval
Authors: Ma, Yongchao; Chen, Peng; Liu, Tong; Xu, Guochang; Lu, Zhiping
Bibcode: 2022E&SS....902089M
Altcode:
The atmosphere weighted mean temperature, Tm, is an essential
parameter for retrieving precipitable water from the ground-based
Global Navigation Satellite Systems (GNSS). The accuracy of high
temporal resolution GNSS precipitable water vapor (PWV) estimation
requires wideband Tm information and its magnitude. However, existing Tm
empirical models use trigonometric functions with only fixed amplitude
and low-frequency for time fitting, which limits real-time or near
real-time PWV retrieval from GNSS observation. Thus, an improved
Tm model for China, LTCm, containing more frequency information
of Tm, based on the antileakage least-squares spectrum analysis by
utilizing the ERA5 pressure-level products during the years 2015-2019,
is developed. Both Tm data from ERA5 pressure-level products and
radiosonde stations distributed in China over 2020 are selected as
reference values to verify the performance of the LCTm model. The
results show that the LCTm model yields significant performance
against other models in Tm estimation over China, especially in
marine regions and high-altitude areas. Furthermore, the LCTm model
can generally achieve a mean Bias/root mean square (RMS) of −0.33
K/2.06 K in contrast to ERA5 pressure-level products and 0.03 K/3.47
K in comparison with radiosonde, which corresponds to a 7.2%-13.8%
improvement against GPT2w, GTm-III, and Bevis. Moreover, LCTm has
σpwv and σpwv/PWV values of 0.27 mm and 1.25%
when used to retrieve GNSS-PWV, respectively. Consequently, the LCTm
model that considers high-frequency information of Tm can obtain
more reliable Tm values. Therefore, the LCTm model can be applied
to real-time or near real-time GNSS PWV retrieval, which is of great
significance for GNSS meteorological research.
Title: A fast radio burst source at a complex magnetised site in a
barred galaxy
Authors: Xu, H.; Niu, J. R.; Chen, P.; Lee, K. J.; Zhu, W. W.; Dong,
S.; Zhang, B.; Jiang, J. C.; Wang, B. J.; Xu, J. W.; Zhang, C. F.;
Fu, H.; Filippenko, A. V.; Peng, E. W.; Zhou, D. J.; Zhang, Y. K.;
Wang, P.; Feng, Y.; Li, Y.; Brink, T. G.; Li, D. Z.; Lu, W.; Yang,
Y. P.; Caballero, R. N.; Cai, C.; Chen, M. Z.; Dai, Z. G.; Djorgovski,
S. G.; Esamdin, A.; Gan, H. Q.; Guhathakurta, P.; Han, J. L.; Hao,
L. F.; Huang, Y. X.; Jiang, P.; Li, C. K.; Li, D.; Li, H.; Li, X. Q.;
Li, Z. X.; Liu, Z. Y.; Luo, R.; Men, Y. P.; Niu, C. H.; Peng, W. X.;
Qian, L.; Song, L. M.; Stern, D.; Stockton, A.; Sun, J. H.; Wang,
F. Y.; Wang, M.; Wang, N.; Wang, W. Y.; Wu, X. F.; Xiao, S.; Xiong,
S. L.; Xu, Y. H.; Xu, R. X.; Yang, J.; Yang, X.; Yao, R.; Yi, Q. B.;
Yue, Y. L.; Yu, D. J.; Yu, W. F.; Yuan, J. P.; Zhang, B. B.; Zhang,
S. B.; Zhang, S. N.; Zhao, Y.; Zheng, W. K.; Zhu, Y.; Zou, J. H.
Bibcode: 2021arXiv211111764X
Altcode:
Fast radio bursts (FRBs) are highly dispersed radio bursts prevailing
in the universe. The recent detection of FRB~200428 from a Galactic
magnetar suggested that at least some FRBs originate from magnetars, but
it is unclear whether the majority of cosmological FRBs, especially the
actively repeating ones, are produced from the magnetar channel. Here
we report the detection of 1863 polarised bursts from the repeating
source FRB~20201124A during a dedicated radio observational campaign
of Five-hundred-meter Aperture Spherical radio Telescope (FAST). The
large sample of radio bursts detected in 88\,hr over 54 days indicate
a significant, irregular, short-time variation of the Faraday rotation
measure (RM) of the source during the first 36 days, followed by a
constant RM during the later 18 days. Significant circular polarisation
up to 75\% was observed in a good fraction of bursts. Evidence suggests
that some low-level circular polarisation originates from the conversion
from linear polarisation during the propagation of the radio waves,
but an intrinsic radiation mechanism is required to produce the higher
degree of circular polarisation. All of these features provide evidence
for a more complicated, dynamically evolving, magnetised immediate
environment around this FRB source. Its host galaxy was previously
known. Our optical observations reveal that it is a Milky-Way-sized,
metal-rich, barred-spiral galaxy at redshift $z=0.09795\pm0.00003$,
with the FRB source residing in a low stellar density, interarm region
at an intermediate galactocentric distance, an environment not directly
expected for a young magnetar formed during an extreme explosion of
a massive star.
Title: VizieR Online Data Catalog: 500days of ASASSN-18pg
multiwavelength obs. (Holoien+, 2020)
Authors: Holoien, T. W. -S.; Auchettl, K.; Tucker, M. A.; Shappee,
B. J.; Patel, S. G.; Miller-Jones, J. C. A.; Mockler, B.; Groenewald,
D. N.; Hinkle, J. T.; Brown, J. S.; Kochanek, C. S.; Stanek, K. Z.;
Chen, P.; Dong, S.; Prieto, J. L.; Thompson, T. A.; Beaton, R. L.;
Connor, T.; Cowperthwaite, P. S.; Dahmen, L.; French, K. D.; Morrell,
N.; Buckley, D. A. H.; Gromadzki, M.; Roy, R.; Coulter, D. A.;
Dimitriadis, G.; Foley, R. J.; Kilpatrick, C. D.; Piro, A. L.;
Rojas-Bravo, C.; Siebert, M. R.; van Velzen, S.
Bibcode: 2021yCat..18980161H
Altcode:
The All-Sky Automated Survey for Supernovae (ASAS-SN; Shappee+ 2014,
J/ApJ/788/48) currently is composed of five units hosted by the Las
Cumbres Observatory global telescope network in Hawaii, Chile, Texas,
and South Africa. To construct the V-band reference image, we used only
data obtained prior to 2018 May 1, and for the g-band reference image,
we used only data obtained after 2019 April 1. See Section 2.2. Our initial Swift follow-up campaign included 25 epochs of TOO
observations between 2018 July 18 and 2018 November 6. We obtained
an additional 28 epochs of observations between 2019 January 22 and
2019 October 29. UVOT observations were obtained in the V (5468Å), B
(4392Å), U (3465Å), UVW1 (2600Å), UVM2 (2246Å), and UVW2 (1928Å)
filters in most epochs. See Section 2.3. We also obtained uBVgri
observations from the Swope 1m telescope at Las Campanas Observatory
and BVgri observations from the Las Cumbres Observatory 0.4 and 1m
telescopes located in Cerro Tololo, Chile; Siding Spring, Australia; and
Sutherland, South Africa. See Section 2.4. We began spectroscopic
follow-up observations of ASASSN-18pg following its classification
as a possible TDE and continued to monitor it regularly through 2019
September. Our follow-up spectra were obtained with the Robert Stobie
Spectrograph (RSS) on the 10m SALT, the Gemini Multi-Object Spectrograph
(GMOS) on the 8.4m Gemini South telescope, the Inamori-Magellan Areal
Camera and Spectrograph (IMACS) on the 6.5m Magellan-Baade telescope,
LDSS-3 on the 6.5m Magellan Clay telescope, the Goodman Spectrograph
on the Southern Astrophysical Research (SOAR) 4.1m telescope, and
the Wide Field Reimaging CCD Camera (WFCCD) on the du Pont 100 inch
telescope. Our observations span from 26 days prior to peak light
through 272 days after and include several spectra taken near or before
peak light. See Section 2.5. We observed ASASSN-18pg using the
Australia Telescope Compact Array (ATCA) in the 15mm band, using the
Compact Array Broadband Backend to provide 2x2048MHz of bandwidth,
centered at 16.7 and 21.2GHz. Our initial observation was made on 2018
July 20 (08:18-13:29 UT). We made a second ATCA observation on 2018
August 6 (12:20-17:18 UT). We conclude that ASASSN-18pg was not detected
in the radio. We note, however, that both of these observations were
taken prior to ASASSN-18pg reaching its peak brightness (see Section
3.1), so it is possible that the tidal disruption event (TDE) could
have exhibited radio emission at later times that was not detectable
prior to peak. See Section 2.6. (2 data files).
Title: Particle-in-cell Simulation of 3He Enrichment in
Solar Energetic Particle Events
Authors: Li, T. M.; Li, C.; Ding, W. J.; Chen, P. F.
Bibcode: 2021ApJ...922...50L
Altcode:
3He enrichment is one distinctive feature of impulsive
solar energetic particle events. This study is designed to
investigate the process of plasma wave-particle resonance,
which plays a key role in selectively accelerating heavy ions. We
apply a 1.5 dimensional particle-in-cell simulation to model the
electron-beam-plasma interaction that generates electron and ion
cyclotron waves, namely proton and 4He cyclotron waves,
whose dispersions are dependent on the magnetization parameter α
= ω pe/Ωce and the temperature ratio τ =
T e /T p . The background particles, e.g.,
3He and 4He, resonate with the excited cyclotron
waves and experience selective heating or acceleration. Specifically,
the resonant modes of 3He ions lead to a more effective
acceleration rate compared to those of the 4He ions. The
simulation results provide a potential solution for understanding the
abundance of heavy ions in the solar wind.
Title: h5py/h5py: 3.5.0
Authors: Collette, Andrew; Kluyver, Thomas; Caswell, Thomas A;
Tocknell, James; Kieffer, Jerome; Jelenak, Aleksandar; Scopatz,
Anthony; Dale, Darren; Chen; VINCENT, Thomas; Payno; Juliagarriga;
Sciarelli, Pierlauro; Valls, Valentin; Ghosh, Satrajit; Kofoed
Pedersen, Ulrik; Jakirkham; Raspaud, Martin; Danilevski, Cyril;
Abbasi, Hameer; Readey, John; Paramonov, Andrey; Chan, Lawrence; Solé,
V. Armando; Jialin; Feng, Yu; Vaillant, Ghislain Antony; Teichmann,
Martin; Brucher, Matthieu; Johnson, Seth R.
Bibcode: 2021zndo...5585380C
Altcode:
HDF5 for Python -- The h5py package is a Pythonic interface to the
HDF5 binary data format.
Title: h5py/h5py: 3.5.0
Authors: Collette, Andrew; Kluyver, Thomas; Caswell, Thomas A;
Tocknell, James; Kieffer, Jerome; Jelenak, Aleksandar; Scopatz,
Anthony; Dale, Darren; Chen; VINCENT, Thomas; Payno; Juliagarriga;
Sciarelli, Pierlauro; Valls, Valentin; Ghosh, Satrajit; Kofoed
Pedersen, Ulrik; Jakirkham; Raspaud, Martin; Danilevski, Cyril;
Abbasi, Hameer; Readey, John; Paramonov, Andrey; Chan, Lawrence; Solé,
V. Armando; Jialin; Feng, Yu; Vaillant, Ghislain Antony; Teichmann,
Martin; Brucher, Matthieu; Johnson, Seth R.
Bibcode: 2021zndo....594310C
Altcode:
HDF5 for Python -- The h5py package is a Pythonic interface to the
HDF5 binary data format.
Title: Formation and Characteristics of Filament Threads in
Double-dipped Magnetic Flux Tubes
Authors: Guo, J. H.; Zhou, Y. H.; Guo, Y.; Ni, Y. W.; Karpen, J. T.;
Chen, P. F.
Bibcode: 2021ApJ...920..131G
Altcode: 2021arXiv210712181G
As one of the main formation mechanisms of solar filament formation, the
chromospheric evaporation-coronal condensation model has been confirmed
by numerical simulations to explain the formation of filament threads
very well in flux tubes with single dips. However, coronal magnetic
extrapolations indicated that some magnetic field lines might possess
more than one dip. It is expected that the formation process would
be significantly different in this case compared to a single-dipped
magnetic flux tube. In this paper, based on the evaporation-condensation
model, we study filament thread formation in double-dipped magnetic
flux tubes by numerical simulations. We find that only with particular
combinations of magnetic configuration and heating, e.g., concentrated
localized heating and a long magnetic flux tube with deep dips,
can two threads form and persist in a double-dipped magnetic flux
tube. Comparing our parametric survey with observations, we conclude
that such magnetically connected threads due to multiple dips are
more likely to exist in quiescent filaments than in active-region
filaments. Moreover, we find that these threads are usually shorter
than independently trapped threads, which might be one of the reasons
why quiescent filaments have short threads. These characteristics of
magnetically connected threads could also explain barbs and vertical
threads in quiescent filaments.
Title: Editorial: Data-driven MHD -Novel Applications to the Solar
Atmosphere
Authors: Srivastava, A. K.; Erdélyi, R.; Poedts, S.; Chen, P. F.;
Yan, Y.
Bibcode: 2021FrASS...8..140S
Altcode:
No abstract at ADS
Title: Particle-in-cell simulation of plasma emission in solar
radio bursts
Authors: Li, T. M.; Li, C.; Chen, P. F.; Ding, W. J.
Bibcode: 2021A&A...653A.169L
Altcode:
Aims: The present study aims to shed light on our understanding
of the radiation processes of solar radio bursts associated with
nonthermal electron propagation in the corona and interplanetary
space.
Methods: We performed 2.5-dimensional particle-in-cell
(PIC) simulations to investigate the plasma emission excited by
a relativistic electron beam using different pitch angles in the
magnetized plasma.
Results: Langmuir waves at the fundamental
and harmonic frequencies were excited via the energy dissipation of
the electron beam. For the first time, the backward Langmuir waves
up to the third harmonic frequencies were reproduced in the cases of
large pitch angles, likely arising from the relecting and scattering
of density fluctuations to the Langmuir waves during electrom
beam-plasma interaction. Electromagnetic (EM) waves were generated
via the mode conversion of electrostatic (ES) waves and the nonlinear
wave coupling. Specifically, the harmonic EM emission comes from the
coupling of forward and backward Langmuir waves, namely, L + L' → 2H,
while the higher harmonic EM emissions generally come from the coupling
of the Langmuir wave and lower-order harmonic EM wave, namely, L +
(n − 1)H → nH. When the electron beam exhibits a large pitch angle,
another possible mechanism for the third harmonic EM emission might
be the coalescence of three ES waves, namely, L + L' + L″ → 3H.
Title: Data-constrained Magnetohydrodynamic Simulation of a
Long-duration Eruptive Flare
Authors: Guo, Yang; Zhong, Ze; Ding, M. D.; Chen, P. F.; Xia, Chun;
Keppens, Rony
Bibcode: 2021ApJ...919...39G
Altcode: 2021arXiv210615080G
We perform a zero-β magnetohydrodynamic simulation for the C7.7
class flare initiated at 01:18 UT on 2011 June 21 using the Message
Passing Interface Adaptive Mesh Refinement Versatile Advection Code
(MPI-AMRVAC). The initial condition for the simulation involves a
flux rope, which we realize through the regularized Biot-Savart laws,
whose parameters are constrained by observations from the Atmospheric
Imaging Assembly (AIA) on the Solar Dynamics Observatory (SDO) and
the Extreme Ultraviolet Imager (EUVI) on the twin Solar Terrestrial
Relations Observatory (STEREO). This data-constrained initial state
is then relaxed to a force-free state by the magnetofrictional module
in MPI-AMRVAC. The further time-evolving simulation results reproduce
the eruption characteristics obtained by SDO/AIA 94 Å, 304 Å, and
STEREO/EUVI 304 Å observations fairly well. The simulated flux rope
possesses similar eruption direction, height range, and velocity to
the observations. In particular, the two phases of slow evolution
and fast eruption are reproduced by varying the density distribution
in the light of the draining process of the filament material. Our
data-constrained simulations also show other advantages, such as a
large field of view (about 0.76 R⊙). We study the twist
of the magnetic flux rope and the decay index of the overlying field,
and find that in this event, both the magnetic strapping force and the
magnetic tension force are sufficiently weaker than the magnetic hoop
force, thus allowing the successful eruption of the flux rope. We also
find that the anomalous resistivity is necessary to keep the correct
morphology of the erupting flux rope.
Title: VizieR Online Data Catalog: Multiband photometry of
microlensing event Kojima-1 (Zang+, 2020)
Authors: Zang, W.; Dong, S.; Gould, A.; Calchi Novati, S.; Chen, P.;
Yang, H.; Li, S. -S.; Mao, S.; Alton, K. B.; Brimacombe, J.; Carey,
S.; Christie, G. W.; Delplancke-Strobele, F.; Feliz, D. L.; Gaudi,
B. S.; Green, J.; Hu, S.; Jayasinghe, T.; Koff, R. A.; Kurtenkov, A.;
Merand, A.; Minev, M.; Mutel, R.; Natusch, T.; Roth, T.; Shvartzvald,
Y.; Sun, F.; Vanmunster, T.; Zhu, W.
Bibcode: 2021yCat..18970180Z
Altcode:
We use ground-based follow-up data to derive basic single-lens
parameters and constrain microlens parallax. To minimize the impact
on microlens parallax measurements from possible systematic errors,
we choose the ground-based data that were carefully selected and
used by Dong+, 2019ApJ...871...70D, including the data from All-Sky
Automatic Survey for Supernovae (ASAS-SN), 0.6m telescopes at Post
Observatory (RP), 0.5m Iowa Robotic Telescope (Iowa) at the Winer
Observatory (Arizona, USA), 0.4m telescope at Auckland Observatory
(AO), and the 1.3m SMARTS telescope at Cerro Tololo Inter-American
Observatory (CTIO). For Spitzer, observations start on 2017 December 19
(HJD'=8107.2, HJD'=HJD-2450000). The observations ended on 2018 January
23 (HJD'=8143.7). In total, 21 data points were taken, all using the
3.6μm channel (L-band) of the IRAC camera. (1 data file).
Title: Fine Structures of an EUV Wave Event from Multi-viewpoint
Observations
Authors: Chandra, Ramesh; Chen, P. F.; Devi, Pooja; Joshi, Reetika;
Schmieder, Brigitte; Moon, Yong-Jae; Uddin, Wahab
Bibcode: 2021ApJ...919....9C
Altcode: 2021arXiv210614024C
In this study, we investigate an extreme ultraviolet (EUV) wave event
on 2010 February 11, which occurred as a limb event from the Earth
viewpoint and a disk event from the Solar Terrestrial Relations
Observatory-Behind viewpoint. We use the data obtained by the
Atmospheric Imaging Assembly on board the Solar Dynamics Observatory
in various EUV channels. The EUV wave event was launched by a partial
prominence eruption. Compared with some EUV wave events in previous
works, this EUV wave event contains a faster wave with a speed of
~445 ± 6 km s-1, which we call a coronal Moreton wave,
and a slower wave with a speed of ~298 ± 5 km s-1, which
we call the Extreme Ultraviolet Imaging Telescope (EIT) wave. The
coronal Moreton wave is identified as a fast-mode wave and the EIT
wave is identified as an apparent propagation due to successive
field-line stretching. We also observe a stationary front associated
with the fast-mode EUV wave. This stationary front is explained as
mode conversion from the coronal Moreton wave to a slow-mode wave near
a streamer.
Title: How low can you go? SN 2018zd as a low-mass Fe core-collapse
supernova
Authors: Callis, E.; Fraser, M.; Pastorello, A.; Dong, Subo; Brennan,
S. J.; Chen, P.; Bose, S.; Reynolds, T.; Salmon, L.; Jonker, P.;
Benetti, S.; Berton, M.; Cannizzaro, G.; Cappellaro, E.; Congiu, E.;
Dyrbye, S.; Eappachen, D.; Elias-Rosa, N.; Gromadzki, M.; Gutiérrez,
C. P.; Holmbo, S.; Holoien, T. W. S.; Itagaki, K.; Kankare, E.;
Mattila, S.; Mutel, R.; Ochner, P.; Post, R. S.; Prieto, J.; Reguitti,
A.; Roth, T.; Ryon, J.; Sagués-Carracedo, A.; Shappee, B. J.; Siviero,
A.; Stassun, K. G.; Stritzinger, M.; Tomasella, L.; Villanueva, S.,
Jr.; Wevers, T.; Wiggins, P.
Bibcode: 2021arXiv210912943C
Altcode:
We present spectroscopy and photometry of SN 2018zd, a Type
IIP core-collapse supernova with signatures of interaction with
circumstantial material in its earliest spectra. High ionization
lines, the earmark of shock breakout, are not seen in the earliest
spectral epoch, and are only seen in a single spectrum at 4.9 d
after explosion. The strength and brevity of these features imply a
confined circumstellar material shell in the immediate vicinity of
the progenitor. Once the narrow emission lines disappear, SN 2018zd
evolves similarly to a Type IIP SN, although the blue colour and
enhanced plateau magnitude of SN 2018zd suggests an additional source of
luminosity throughout the plateau phase. While SN 2018zd has previously
been proposed as an electron-capture SN, we suggest that it is an Fe
core-collapse from a low mass red supergiant progenitor. Differences in
interpretation for SN 2018zd arise in part due to the large uncertainty
on the distance to the host-galaxy NGC 2146, which we re-derive here
to be $15.6^{+6.1}_{-3.0}$ Mpc. We find the ejected $^{56}$Ni mass for
SN 2018zd to be 0.017 M$_{\odot}$, significantly higher than models
of ECSNe predict. We also find the Ni/Fe ratio in SN 2018zd to be much
lower that would be expected for an ECSN.
Title: Magnetic Twists of Solar Filaments
Authors: Guo, J. H.; Ni, Y. W.; Qiu, Y.; Zhong, Z.; Guo, Y.; Chen,
P. F.
Bibcode: 2021ApJ...917...81G
Altcode: 2021arXiv210702580G
Solar filaments are cold and dense materials situated in magnetic
dips, which show distinct radiation characteristics compared to
the surrounding coronal plasma. They are associated with coronal
sheared and twisted magnetic field lines. However, the exact magnetic
configuration supporting a filament material is not easy to ascertain
because of the absence of routine observations of the magnetic field
inside filaments. Since many filaments lie above weak-field regions,
it is nearly impossible to extrapolate their coronal magnetic structures
by applying the traditional methods to noisy photospheric magnetograms,
in particular the horizontal components. In this paper, we construct
magnetic structures for some filaments with the regularized Biot-Savart
laws and calculate their magnetic twists. Moreover, we make a parameter
survey for the flux ropes of the Titov-Démoulin-modified model to
explore the factors affecting the twist of a force-free magnetic
flux rope. It is found that the twist of a force-free flux rope, $|
\overline{{T}_{{\rm{w}}}}| $ , is proportional to its ratio of axial
length to minor radius, L/a, and is basically independent of the
overlying background magnetic field strength. Thus, we infer that
long quiescent filaments are likely to be supported by more twisted
flux ropes than short active-region filaments, which is consistent
with observations.
Title: Accuracy analysis of ground-based GNSS-R sea level monitoring
based on multi GNSS and multi SNR
Authors: Zheng, Naiquan; Chen, Peng; Li, Zheng
Bibcode: 2021AdSpR..68.1789Z
Altcode:
With the expansion of GNSS applications, Global Navigation Satellite
System Reflectometry (GNSS-R) technology has become an essential
means for sea level monitoring. The development and improvement of
multi-GNSS have brought new opportunities for ground-based GNSS-R
sea level inversion research. More than 100 satellites in orbit
are expected to improve the time resolution and the reliability
of inversion results significantly. And GNSS-R technology is
an SNR-based inversion technology. With the opening of different
frequency channels of various GNSS systems, more signal-to-noise ratio
(SNR) types are available. Therefore, the research on the multi-GNSS
sea level inversion was carried out, and the multi signals inversion
accuracy was analyzed. Based on the 2017-2019 observation data of the
MAYG on the east coast of Africa, the SNR of the navigation satellite
signal is used to invert the sea level. The results show that the
time resolution of multi-GNSS inversion is significantly improved,
and the average number of inversions per day reaches 51. The time
interval between the two inversion results is only 18.5 min, which
is 2.4 times that of GPS alone. There is a high agreement between the
inversion results and the measured values. The root mean square error
(RMSE) of the two is 0.36 m, and the correlation coefficient (R) is
0.93. In particular, the BDS of 2019 is monitored. It is concluded that
BDS2-GEO is not suitable for coastal altimetry, the monitoring accuracy
of BDS2-MEO is better than that of BDS2-IGSO and the monitoring effect
of BDS3-MEO is equal to that of BDS2-MEO.
Title: Nebular Hα emission in Type Ia supernova 2016jae
Authors: Elias-Rosa, N.; Chen, P.; Benetti, S.; Dong, S.; Prieto,
J. L.; Cappellaro, E.; Kollmeier, J. A.; Morrell, N.; Piro, A. L.;
Phillips, M. M.
Bibcode: 2021A&A...652A.115E
Altcode: 2021arXiv210615340E
There is a wide consensus that Type Ia supernovae (SNe Ia) originate
from the thermonuclear explosion of CO white dwarfs (WDs), with the lack
of hydrogen in the observed spectra as a distinctive feature. Here, we
present supernova (SN) 2016jae, which was classified as an SN Ia from
a spectrum obtained soon after its discovery. The SN reached a B-band
peak of −17.93 ± 0.34 mag, followed by a fast luminosity decline
with sBV0.56 ± 0.06 and inferred Δm15(B) of
1.88 ± 0.10 mag. Overall, the SN appears to be a `transitional'
event between a `normal' SN Ia and a very dim SN Ia, such as
91bg-like SNe. Its peculiarity is that two late-time spectra, taken
at +84 and +142 days after the peak, show a narrow line of Hα (with
full width at half maximum of ∼650 and 1000 km s−1,
respectively). This is the third low-luminosity and fast-declining
SN Ia, after SN2018cqj/ATLAS18qtd and SN2018fhw/ASASSN-18tb, found
in the 100IAS survey to show a resolved narrow Hα line in emission
in its nebular-phase spectra. We argue that the nebular Hα emission
originates in an expanding hydrogen-rich shell (with velocity ≤1000
km s−1). The hydrogen shell velocity is too high to be
produced during a common envelope phase, though it may be consistent
with some material stripped from an H-rich companion star in a
single-degenerate progenitor system. However, the derived mass of
this stripped hydrogen is ∼0.002-0.003 M⊙, which is
much less than that expected (> 0.1 M⊙) from standard
models for these scenarios. Another plausible sequence of events is a
weak SN ejecta interaction with an H shell ejected by optically thick
winds or a nova-like eruption on the CO WD progenitor some years before
the SN explosion.
Title: The Payload for Ultrahigh Energy Observations (PUEO): a
white paper
Authors: Abarr, Q.; Allison, P.; Ammerman Yebra, J.; Alvarez-Muñiz,
J.; Beatty, J. J.; Besson, D. Z.; Chen, P.; Chen, Y.; Xie, C.;
Clem, J. M.; Connolly, A.; Cremonesi, L.; Deaconu, C.; Flaherty, J.;
Frikken, D.; Gorham, P. W.; Hast, C.; Hornhuber, C.; Huang, J. J.;
Hughes, K.; Hynous, A.; Ku, Y.; Kuo, C. -Y.; Liu, T. C.; Martin,
Z.; Miki, C.; Nam, J.; Nichol, R. J.; Nishimura, K.; Novikov, A.;
Nozdrina, A.; Oberla, E.; Prohira, S.; Prechelt, R.; Rauch, B. F.;
Roberts, J. M.; Romero-Wolf, A.; Russell, J. W.; Seckel, D.; Shiao,
J.; Smith, D.; Southall, D.; Varner, G. S.; Vieregg, A. G.; Wang,
S. -H.; Wang, Y. -H.; Wissel, S. A.; Young, R.; Zas, E.; Zeolla, A.;
The PUEO collaboration
Bibcode: 2021JInst..16P8035A
Altcode: 2020arXiv201002892A
The Payload for Ultrahigh Energy Observations (PUEO) long-duration
balloon experiment is designed to have world-leading sensitivity to
ultrahigh-energy neutrinos at energies above 1 EeV. Probing this energy
region is essential for understanding the extreme-energy universe at
all distance scales. PUEO leverages experience from and supersedes
the successful Antarctic Impulsive Transient Antenna (ANITA) program,
with an improved design that drastically improves sensitivity by more
than an order of magnitude at energies below 30 EeV. PUEO will either
make the first significant detection of or set the best limits on
ultrahigh-energy neutrino fluxes.
Title: Accuracy evaluation of XUST's global ionospheric products
Authors: Chen, Peng; Liu, Lixia; Liu, Hang; Yao, Wanqiang
Bibcode: 2021AdSpR..68..201C
Altcode:
The ionosphere research team of Xi'an University of Science and
Technology (XUST) has been committing to high-precision global
ionospheric modeling research since 2012. The agency adopted spherical
harmonic functions to generate GNSS (Global Navigation Satellite System)
global ionospheric product XANG and multi-source data fusion global
ionospheric product XAMG. In this essay, we take International GNSS
Service (IGS) global ionospheric maps (GIMs) products as a reference
to verify and analyze the accuracy of GIMs products produced by XUST
in detail from three different aspects. The internal and external
evaluation results of GNSS dSTEC indicate that the GIMs products of XUST
are consistent with the GIMs products of other analysis centers. In
contrast to the Jason-2/-3 VTEC, the STD between XANG and Jason-2
during 2016-2018 is about 2.42-3.11 TECU. The STD between XANG and
Jason-3 is about 2.40-3.11 TECU, which is equivalent to that of China
Academy of Sciences (CAS) and Jet Propulsion Laboratory (JPL), better
than that of the Center for Orbit Determination in Europe (CODE),
European Space Operations Center of European Space Agency (ESA) and
Wuhan University (WHU), and slightly worse than that of Universitat
Politècnica de Catalunya/IonSAT (UPC). Besides, we figure out that the
accuracy of GIM products in approximately 60% of the ocean areas has
been significantly improved after adding space-based data by comparing
the two developed global ionospheric products. Finally, we evaluated
the product performance of XUST in single-frequency precise point
positioning (SF-PPP) with convergence time and positioning accuracy
of standard single-frequency PPP as reference. In terms of average
convergence time, the ionospheric delay processing capabilities
of XANG and XAMG are comparable to other GIMs and even better than
ESAG and JPLG in some regions. In terms of positioning accuracy, the
positioning accuracy of XANG as an external ionospheric constraint is
better than that of XAMG, and both are better than ESAG, JPLG and IGSG,
and slightly worse than CASG and CODG.
Title: h5py/h5py: 3.3.0
Authors: Collette, Andrew; Kluyver, Thomas; Caswell, Thomas A;
Tocknell, James; Kieffer, Jerome; Scopatz, Anthony; Jelenak,
Aleksandar; Dale, Darren; Chen; payno; juliagarriga; VINCENT,
Thomas; Sciarelli, Pierlauro; Valls, Valentin; Ghosh, Satrajit;
Kofoed Pedersen, Ulrik; jakirkham; Raspaud, Martin; Danilevski, Cyril;
Abbasi, Hameer; Readey, John; Paramonov, Andrey; Chan, Lawrence; Solé,
V. Armando; jialin; Feng, Yu; Vaillant, Ghislain Antony; Teichmann,
Martin; Brucher, Matthieu; Johnson, Seth R.
Bibcode: 2021zndo...5012627C
Altcode:
HDF5 for Python -- The h5py package is a Pythonic interface to the
HDF5 binary data format.
Title: Analyses of Laser Propagation Noises for TianQin Gravitational
Wave Observatory Based on the Global Magnetosphere MHD Simulations
Authors: Su, Wei; Wang, Yan; Zhou, Chen; Lu, Lingfeng; Zhou, Ze-Bing;
Li, T. M.; Shi, Tong; Hu, Xin-Chun; Zhou, Ming-Yue; Wang, Ming; Yeh,
Hsien-Chi; Wang, Han; Chen, P. F.
Bibcode: 2021ApJ...914..139S
Altcode: 2021arXiv210210574S
TianQin is a proposed space-borne gravitational-wave (GW) observatory
composed of three identical satellites orbiting around the geocenter
with a radius of 105 km. It aims at detecting GWs in
the frequency range of 0.1 mHz-1 Hz. The detection of GW relies
on the high-precision measurement of optical path length at the
10-12 m level. The dispersion of space plasma can lead
to the optical path difference (OPD, Δl) along the propagation of
laser beams between any pair of satellites. Here, we study the OPD
noises for TianQin. The Space Weather Modeling Framework is used to
simulate the interaction between the Earth magnetosphere and solar
wind. From the simulations, we extract the magnetic field and plasma
parameters on the orbits of TianQin at four relative positions of
the satellite constellation in the Earth magnetosphere. We calculate
the OPD noise for single link, Michelson combination, and Time-Delay
Interferometry (TDI) combinations (α and X). For single link and
Michelson interferometer, the maxima of ∣Δl∣ are on the order of
1 pm. For the TDI combinations, these can be suppressed to about 0.004
and 0.008 pm for α and X. The OPD noise of the Michelson combination
is colored in the concerned frequency range; while the ones for the
TDI combinations are approximately white. Furthermore, we calculate
the ratio of the equivalent strain of the OPD noise to that of TQ,
and find that the OPD noises for the TDI combinations can be neglected
in the most sensitive frequency range of TQ.
Title: IceCube-Gen2: the window to the extreme Universe
Authors: Aartsen, M. G.; Abbasi, R.; Ackermann, M.; Adams, J.; Aguilar,
J. A.; Ahlers, M.; Ahrens, M.; Alispach, C.; Allison, P.; Amin,
N. M.; Andeen, K.; Anderson, T.; Ansseau, I.; Anton, G.; Argüelles,
C.; Arlen, T. C.; Auffenberg, J.; Axani, S.; Bagherpour, H.; Bai, X.;
Balagopal V, A.; Barbano, A.; Bartos, I.; Bastian, B.; Basu, V.; Baum,
V.; Baur, S.; Bay, R.; Beatty, J. J.; Becker, K. -H.; Tjus, J. Becker;
BenZvi, S.; Berley, D.; Bernardini, E.; Besson, D. Z.; Binder, G.;
Bindig, D.; Blaufuss, E.; Blot, S.; Bohm, C.; Bohmer, M.; Böser, S.;
Botner, O.; Böttcher, J.; Bourbeau, E.; Bourbeau, J.; Bradascio,
F.; Braun, J.; Bron, S.; Brostean-Kaiser, J.; Burgman, A.; Burley,
R. T.; Buscher, J.; Busse, R. S.; Bustamante, M.; Campana, M. A.;
Carnie-Bronca, E. G.; Carver, T.; Chen, C.; Chen, P.; Cheung, E.;
Chirkin, D.; Choi, S.; Clark, B. A.; Clark, K.; Classen, L.; Coleman,
A.; Collin, G. H.; Connolly, A.; Conrad, J. M.; Coppin, P.; Correa,
P.; Cowen, D. F.; Cross, R.; Dave, P.; Deaconu, C.; De Clercq, C.;
DeLaunay, J. J.; De Kockere, S.; Dembinski, H.; Deoskar, K.; De Ridder,
S.; Desai, A.; Desiati, P.; de Vries, K. D.; de Wasseige, G.; de With,
M.; DeYoung, T.; Dharani, S.; Diaz, A.; Díaz-Vélez, J. C.; Dujmovic,
H.; Dunkman, M.; DuVernois, M. A.; Dvorak, E.; Ehrhardt, T.; Eller,
P.; Engel, R.; Evans, J. J.; Evenson, P. A.; Fahey, S.; Farrag, K.;
Fazely, A. R.; Felde, J.; Fienberg, A. T.; Filimonov, K.; Finley,
C.; Fischer, L.; Fox, D.; Franckowiak, A.; Friedman, E.; Fritz, A.;
Gaisser, T. K.; Gallagher, J.; Ganster, E.; Garcia-Fernandez, D.;
Garrappa, S.; Gartner, A.; Gerhard, L.; Gernhaeuser, R.; Ghadimi, A.;
Glaser, C.; Glauch, T.; Glüsenkamp, T.; Goldschmidt, A.; Gonzalez,
J. G.; Goswami, S.; Grant, D.; Grégoire, T.; Griffith, Z.; Griswold,
S.; Gündüz, M.; Haack, C.; Hallgren, A.; Halliday, R.; Halve,
L.; Halzen, F.; Hanson, J. C.; Hanson, K.; Hardin, J.; Haugen, J.;
Haungs, A.; Hauser, S.; Hebecker, D.; Heinen, D.; Heix, P.; Helbing,
K.; Hellauer, R.; Henningsen, F.; Hickford, S.; Hignight, J.; Hill,
C.; Hill, G. C.; Hoffman, K. D.; Hoffmann, B.; Hoffmann, R.; Hoinka,
T.; Hokanson-Fasig, B.; Holzapfel, K.; Hoshina, K.; Huang, F.; Huber,
M.; Huber, T.; Huege, T.; Hughes, K.; Hultqvist, K.; Hünnefeld, M.;
Hussain, R.; In, S.; Iovine, N.; Ishihara, A.; Jansson, M.; Japaridze,
G. S.; Jeong, M.; Jones, B. J. P.; Jonske, F.; Joppe, R.; Kalekin,
O.; Kang, D.; Kang, W.; Kang, X.; Kappes, A.; Kappesser, D.; Karg,
T.; Karl, M.; Karle, A.; Katori, T.; Katz, U.; Kauer, M.; Keivani,
A.; Kellermann, M.; Kelley, J. L.; Kheirandish, A.; Kim, J.; Kin,
K.; Kintscher, T.; Kiryluk, J.; Kittler, T.; Kleifges, M.; Klein,
S. R.; Koirala, R.; Kolanoski, H.; Köpke, L.; Kopper, C.; Kopper, S.;
Koskinen, D. J.; Koundal, P.; Kovacevich, M.; Kowalski, M.; Krauss,
C. B.; Krings, K.; Krückl, G.; Kulacz, N.; Kurahashi, N.; Gualda,
C. Lagunas; Lahmann, R.; Lanfranchi, J. L.; Larson, M. J.; Latif,
U.; Lauber, F.; Lazar, J. P.; Leonard, K.; Leszczyńska, A.; Li, Y.;
Liu, Q. R.; Lohfink, E.; LoSecco, J.; Mariscal, C. J. Lozano; Lu,
L.; Lucarelli, F.; Ludwig, A.; Lünemann, J.; Luszczak, W.; Lyu, Y.;
Ma, W. Y.; Madsen, J.; Maggi, G.; Mahn, K. B. M.; Makino, Y.; Mallik,
P.; Mancina, S.; Mandalia, S.; Mariş, I. C.; Marka, S.; Marka, Z.;
Maruyama, R.; Mase, K.; Maunu, R.; McNally, F.; Meagher, K.; Medina,
A.; Meier, M.; Meighen-Berger, S.; Merz, J.; Meyers, Z. S.; Micallef,
J.; Mockler, D.; Momenté, G.; Montaruli, T.; Moore, R. W.; Morse,
R.; Moulai, M.; Muth, P.; Naab, R.; Nagai, R.; Nam, J.; Nauman, U.;
Necker, J.; Neer, G.; Nelles, A.; Nguyễn, L. V.; Niederhausen, H.;
Nisa, M. U.; Nowicki, S. C.; Nygren, D. R.; Oberla, E.; Pollmann,
A. Obertacke; Oehler, M.; Olivas, A.; O'Sullivan, E.; Pan, Y.; Pandya,
H.; Pankova, D. V.; Papp, L.; Park, N.; Parker, G. K.; Paudel, E. N.;
Peiffer, P.; Pérez de los Heros, C.; Petersen, T. C.; Philippen, S.;
Pieloth, D.; Pieper, S.; Pinfold, J. L.; Pizzuto, A.; Plaisier, I.;
Plum, M.; Popovych, Y.; Porcelli, A.; Rodriguez, M. Prado; Price,
P. B.; Przybylski, G. T.; Raab, C.; Raissi, A.; Rameez, M.; Rauch,
L.; Rawlins, K.; Rea, I. C.; Rehman, A.; Reimann, R.; Renschler, M.;
Renzi, G.; Resconi, E.; Reusch, S.; Rhode, W.; Richman, M.; Riedel, B.;
Riegel, M.; Roberts, E. J.; Robertson, S.; Roellinghoff, G.; Rongen,
M.; Rott, C.; Ruhe, T.; Ryckbosch, D.; Cantu, D. Rysewyk; Safa, I.;
Herrera, S. E. Sanchez; Sandrock, A.; Sandroos, J.; Sandstrom, P.;
Santander, M.; Sarkar, S.; Sarkar, S.; Satalecka, K.; Scharf, M.;
Schaufel, M.; Schieler, H.; Schlunder, P.; Schmidt, T.; Schneider, A.;
Schneider, J.; Schröder, F. G.; Schumacher, L.; Sclafani, S.; Seckel,
D.; Seunarine, S.; Shaevitz, M. H.; Sharma, A.; Shefali, S.; Silva,
M.; Smith, D.; Smithers, B.; Snihur, R.; Soedingrekso, J.; Soldin, D.;
Söldner-Rembold, S.; Song, M.; Southall, D.; Spiczak, G. M.; Spiering,
C.; Stachurska, J.; Stamatikos, M.; Stanev, T.; Stein, R.; Stettner,
J.; Steuer, A.; Stezelberger, T.; Stokstad, R. G.; Strotjohann, N. L.;
Stürwald, T.; Stuttard, T.; Sullivan, G. W.; Taboada, I.; Taketa, A.;
Tanaka, H. K. M.; Tenholt, F.; Ter-Antonyan, S.; Terliuk, A.; Tilav,
S.; Tollefson, K.; Tomankova, L.; Tönnis, C.; Torres, J.; Toscano,
S.; Tosi, D.; Trettin, A.; Tselengidou, M.; Tung, C. F.; Turcati,
A.; Turcotte, R.; Turley, C. F.; Twagirayezu, J. P.; Ty, B.; Unger,
E.; Elorrieta, M. A. Unland; Vandenbroucke, J.; van Eijk, D.; van
Eijndhoven, N.; Vannerom, D.; van Santen, J.; Veberic, D.; Verpoest,
S.; Vieregg, A.; Vraeghe, M.; Walck, C.; Watson, T. B.; Weaver, C.;
Weindl, A.; Weinstock, L.; Weiss, M. J.; Weldert, J.; Welling, C.;
Wendt, C.; Werthebach, J.; Whitehorn, N.; Wiebe, K.; Wiebusch, C. H.;
Williams, D. R.; Wissel, S. A.; Wolf, M.; Wood, T. R.; Woschnagg,
K.; Wrede, G.; Wren, S.; Wulff, J.; Xu, X. W.; Xu, Y.; Yanez, J. P.;
Yoshida, S.; Yuan, T.; Zhang, Z.; Zierke, S.; Zöcklein, M.
Bibcode: 2021JPhG...48f0501A
Altcode: 2020arXiv200804323T
The observation of electromagnetic radiation from radio to
γ-ray wavelengths has provided a wealth of information about the
Universe. However, at PeV (1015 eV) energies and above,
most of the Universe is impenetrable to photons. New messengers,
namely cosmic neutrinos, are needed to explore the most extreme
environments of the Universe where black holes, neutron stars, and
stellar explosions transform gravitational energy into non-thermal
cosmic rays. These energetic particles have millions of times higher
energies than those produced in the most powerful particle accelerators
on Earth. As neutrinos can escape from regions otherwise opaque to
radiation, they allow an unique view deep into exploding stars and
the vicinity of the event horizons of black holes. The discovery
of cosmic neutrinos with IceCube has opened this new window on the
Universe. IceCube has been successful in finding first evidence
for cosmic particle acceleration in the jet of an active galactic
nucleus. Yet, ultimately, its sensitivity is too limited to detect even
the brightest neutrino sources with high significance, or to detect
populations of less luminous sources. In this white paper, we present
an overview of a next-generation instrument, IceCube-Gen2, which will
sharpen our understanding of the processes and environments that govern
the Universe at the highest energies. IceCube-Gen2 is designed to:
Title: Storage Rings and Gravitational Waves: Summary and Outlook
Authors: Berlin, A.; Brüggen, M.; Buchmueller, O.; Chen, P.; D'Agnolo,
R. T.; Deng, R.; Ellis, J. R.; Ellis, S.; Franchetti, G.; Ivanov,
A.; Jowett, J. M.; Kobushkin, A. P.; Lee, S. Y.; Liske, J.; Oide,
K.; Rao, S.; Wenninger, J.; Wellenzohn, M.; Zanetti, M.; Zimmermann, F.
Bibcode: 2021arXiv210500992B
Altcode:
We report some highlights from the ARIES APEC workshop on ``Storage
Rings and Gravitational Waves'' (SRGW2021), held in virtual space
from 2 February to 18 March 2021, and sketch a tentative landscape
for using accelerators and associated technologies for the detection
or generation of gravitational waves.
Title: A Unified Model of Solar Prominence Formation
Authors: Huang, C. J.; Guo, J. H.; Ni, Y. W.; Xu, A. A.; Chen, P. F.
Bibcode: 2021ApJ...913L...8H
Altcode: 2021arXiv210413546H
Several mechanisms have been proposed to account for the formation
of solar prominences or filaments, among which direct injection
and evaporation-condensation models are the two most popular
ones. In the direct injection model, cold plasma is ejected from
the chromosphere into the corona along magnetic field lines; in the
evaporation-condensation model, the cold chromospheric plasma is
heated to over a million degrees and is evaporated into the corona,
where the accumulated plasma finally reaches thermal instability
or nonequilibrium so as to condensate to cold prominences. In this
paper, we try to unify the two mechanisms: The essence of filament
formation is the localized heating in the chromosphere. If the heating
happens in the lower chromosphere, the enhanced gas pressure pushes
the cold plasma in the upper chromosphere to move up to the corona,
such a process is manifested as the direct injection model. If the
heating happens in the upper chromosphere, the local plasma is heated
to 1-2 million degrees, and is evaporated into the corona. Later,
the plasma condensates to form a prominence. Such a process is
manifested as the evaporation-condensation model. With radiative
hydrodynamic simulations we confirmed that the two widely accepted
formation mechanisms of solar prominences can really be unified in
such a single framework. A particular case is also found where both
injection and evaporation-condensation processes occur together.
Title: A search for ultrahigh-energy neutrinos associated with
astrophysical sources using the third flight of ANITA
Authors: Anita Collaboration; Deaconu, C.; Batten, L.; Allison, P.;
Banerjee, O.; Beatty, J. J.; Belov, K.; Besson, D. Z.; Binns, W. R.;
Bugaev, V.; Cao, P.; Chen, C. H.; Chen, P.; Chen, Y.; Clem, J. M.;
Connolly, A.; Cremonesi, L.; Dailey, B.; Dowkontt, P. F.; Fox, B. D.;
Gordon, J. W. H.; Gorham, P. W.; Hast, C.; Hill, B.; Hsu, S. Y.;
Huang, J. J.; Hughes, K.; Hupe, R.; Israel, M. H.; Liewer, K. M.;
Liu, T. C.; Ludwig, A. B.; Macchiarulo, L.; Matsuno, S.; McBride, K.;
Miki, C.; Mulrey, K.; Nam, J.; Naudet, C.; Nichol, R. J.; Novikov, A.;
Oberla, E.; Prohira, S.; Prechelt, R.; Rauch, B. F.; Ripa, J.; Roberts,
J. M.; Romero-Wolf, A.; Rotter, B.; Russell, J. W.; Saltzberg, D.;
Seckel, D.; Schoorlemmer, H.; Shiao, J.; Stafford, S.; Stockham, J.;
Stockham, M.; Strutt, B.; Sutherland, M. S.; Varner, G. S.; Vieregg,
A. G.; Wang, N.; Wang, S. H.; Wissel, S. A.
Bibcode: 2021JCAP...04..017A
Altcode: 2020arXiv201002869D; 2021JCAP...04..017T
The ANtarctic Impulsive Transient Antenna (ANITA) long-duration
balloon experiment is sensitive to interactions of ultrahigh-energy
(E>1018 eV) neutrinos in the Antarctic ice sheet. The
third flight of ANITA, lasting 22 days, began in December 2014. We
develop a methodology to search for energetic neutrinos spatially and
temporally coincident with potential source classes in ANITA data. This
methodology is applied to several source classes: the potential
IceCube-identified neutrino sources TXS 0506+056 and NGC 1068, flaring
high-energy blazars reported by the Fermi All-Sky Variability Analysis,
gamma-ray bursts, and supernovae. Among searches within the five source
classes, one candidate was identified as associated with SN 2015D,
although not at a statistically significant level. We proceed to place
upper limits on the source classes. We further comment on potential
application of this methodology to more sensitive future instruments.
Title: Experimental tests of sub-surface reflectors as an explanation
for the ANITA anomalous events
Authors: Smith, D.; Besson, D. Z.; Deaconu, C.; Prohira, S.; Allison,
P.; Batten, L.; Beatty, J. J.; Binns, W. R.; Bugaev, V.; Cao, P.; Chen,
C.; Chen, P.; Clem, J. M.; Connolly, A.; Cremonesi, L.; Dasgupta, P.;
Gorham, P. W.; Israel, M. H.; Liu, T. C.; Ludwig, A.; Matsuno, S.;
Miki, C.; Nam, J.; Novikov, A.; Nichol, R. J.; Oberla, E.; Prechelt,
R.; Rauch, B. F.; Russell, J.; Saltzberg, D.; Seckel, D.; Varner,
G. S.; Vieregg, A. G.; Wissel, S. A.
Bibcode: 2021JCAP...04..016S
Altcode: 2020arXiv200913010S
The balloon-borne ANITA [1] experiment is designed to detect
ultra-high energy neutrinos via radio emissions produced by in-ice
showers. Although initially purposed for interactions within the
Antarctic ice sheet, ANITA also demonstrated the ability to self-trigger
on radio emissions from ultra-high energy charged cosmic rays [2] (CR)
interacting in the Earth's atmosphere. For showers produced above the
Antarctic ice sheet, reflection of the down-coming radio signals at
the Antarctic surface should result in a polarity inversion prior to
subsequent observation at the ∼35-40 km altitude ANITA gondola. Based
on data taken during the ANITA-1 and ANITA-3 flights, ANITA published
two anomalous instances of upcoming cosmic-rays with measured polarity
opposite the remaining sample of ∼50 UHECR signals [3, 4]. The
steep observed upwards incidence angles (25-30 degrees relative to the
horizontal) require non-Standard Model physics if these events are due
to in-ice neutrino interactions, as the Standard Model cross-section
would otherwise prohibit neutrinos from penetrating the long required
chord of Earth. Shoemaker et al. [5] posit that glaciological effects
may explain the steep observed anomalous events. We herein consider the
scenarios offered by Shoemaker et al. and find them to be disfavored
by extant ANITA and HiCal experimental data. We note that the recent
report of four additional near-horizon anomalous ANITA-4 events [6],
at >3σ significance, are incompatible with their model, which
requires significant signal transmission into the ice.
Title: h5py/h5py: 3.2.1
Authors: Collette, Andrew; Kluyver, Thomas; Caswell, Thomas A;
Tocknell, James; Kieffer, Jerome; Scopatz, Anthony; Dale, Darren; Chen;
Jelenak, Aleksandar; payno; juliagarriga; VINCENT, Thomas; Sciarelli,
Pierlauro; Valls, Valentin; Ghosh, Satrajit; Kofoed Pedersen, Ulrik;
jakirkham; Raspaud, Martin; Parsons, Aaron; Abbasi, Hameer; Readey,
John; Paramonov, Andrey; Chan, Lawrence; Solé, V. Armando; jialin;
Danilevski, Cyril; Feng, Yu; Vaillant, Ghislain Antony; Teichmann,
Martin; Brucher, Matthieu
Bibcode: 2021zndo...4584676C
Altcode:
HDF5 for Python -- The h5py package is a Pythonic interface to the
HDF5 binary data format.
Title: VizieR Online Data Catalog: UV-NIR LCs of the energetic
H-stripped SN2016coi (Terreran+, 2019)
Authors: Terreran, G.; Margutti, R.; Bersier, D.; Brimacombe, J.;
Caprioli, D.; Challis, P.; Chornock, R.; Coppejans, D. L.; Dong, S.;
Guidorzi, C.; Hurley, K.; Kirshner, R.; Migliori, G.; Milisavljevic,
D.; Palmer, D. M.; Prieto, J. L.; Tomasella, L.; Marchant, P.;
Pastorello, A.; Shappee, B. J.; Stanek, K. Z.; Stritzinger, M. D.;
Benetti, S.; Chen, P.; Demarchi, L.; Elias-Rosa, N.; Gall, C.;
Harmanen, J.; Mattila, S.
Bibcode: 2021yCat..18830147T
Altcode:
SN 2016coi was discovered on 2016 May 27.55 UT (MJD57535.55; Holoien+
2016ATel.9086....1H) by the All Sky Automated Survey for SuperNovae
(ASAS-SN; Shappee+ 2014, J/ApJ/788/48) in the irregular galaxy UGC
11868. Our photometric data have been obtained from several
different telescopes and instruments, see Table 3. Our UV-to-NIR
campaign densely samples the evolution of SN 2016coi in its first ~400
days post explosion, with more than 1100 observations distributed
over 166 nights (the gap around 200-300 days corresponds to when SN
2016coi was behind to the Sun). See Section 2. We obtained optical
spectroscopy of SN 2016coi from a few days until t>400days post
explosion with a variety of instruments on different telescopes. The
spectroscopic log can be found in Table 9. See Section 3. We
present in Figure 8 multiband observations of SN 2016coi taken up to
278 days post explosion with the Karl G. Jansky Very Large Array (VLA;
projects 16A-447 and 17A-167). The details of these data are given in
Table 10. See Section 4. The X-Ray Telescope (XRT), on board the
Neil Gehrels Swift Observatory, started observing SN 2016coi on 2016
May 27 (δt~2days post explosion) until 2017 April 17 (δt~326days),
for a total exposure time of 94.4ks. See Section 5. (6 data files).
Title: Triboelectric Backgrounds to radio-based UHE Neutrino
Exeperiments
Authors: Aguilar, J. A.; Anker, A.; Allison, P.; Archambault,
S.; Baldi, P.; Barwick, S. W.; Beatty, J. J.; Beise, J.; Besson,
D.; Bishop, A.; Bondarev, E.; Botner, O.; Bouma, S.; Buitink, S.;
Cataldo, M.; Chen, C. C.; Chen, C. H.; Chen, P.; Chen, Y. C.; Clark,
B. A.; Clay, W.; Curtis-Ginsberg, Z.; Connolly, A.; Dasgupta, P.;
de Kockere, S.; de Vries, K. D.; Deaconu, C.; DuVernois, M. A.;
Flaherty, J.; Friedman, E.; Gaior, R.; Gaswint, G.; Glaser, C.;
Hallgren, A.; Hallmann, S.; Hanson, J. C.; Harty, N.; Hendricks, B.;
Hoffman, K. D.; Hornhuber, C.; Hsu, S. Y.; Hu, L.; Huang, J. J.; Huang,
M. -H.; Hughes, K.; Ishihara, A.; Karle, A.; Kelley, J. L.; Klein,
S. R.; Kleinfelder, S. A.; Kim, K. -C.; Kim, M. -C.; Kravchenko, I.;
Krebs, R.; Ku, Y.; Kuo, C. Y.; Kurusu, K.; Lahmann, R.; Landsman, H.;
Latif, U.; Li, C. -J.; Liu, J.; Liu, T. -C.; Lu, M. -Y.; Madison,
K.; Mammo, J.; Mase, K.; McAleer, S.; Meures, T.; Meyers, Z. S.;
Michaels, K.; Mikhailova, M.; Mulrey, K.; Nam, J.; Nichol, R. J.;
Nelles, A.; Novikov, A.; Nozdrina, A.; Oberla, E.; Oeyen, B.; Osborn,
J.; Pan, Y.; Pandya, H.; Paul, M. P.; Persichilli, C.; Plaisier, I.;
Punsuebsay, N.; Pyras, L.; Rice-Smith, R.; Roth, J.; Ryckbosch, D.;
Scholten, O.; Seckel, D.; Seikh, M. F. H.; Shiao, Y. -S.; Smith, D.;
Southall, D.; Tatar, J.; Torres, J.; Toscano, S.; Tosi, D.; Touart,
J.; Van Den Broeck, D. J.; van Eijndhoven, N.; Varner, G. S.; Vieregg,
A. G.; Wang, M. -Z.; Wang, S. -H; Wang, Y. H.; Welling, C.; Williams,
D. R.; Wissel, S.; Xie, C.; Yoshida, S.; Young, R.; Zhao, L.; Zink, A.
Bibcode: 2021arXiv210306079A
Altcode: 2021arXiv210306079M
The proposed IceCube-Gen2 (ICG2) seeks to instrument ~500 sq. km of
Antarctic ice near the geographic South Pole with radio antennas,
in order to observe the highest energy (E>1 EeV) neutrinos in the
Universe. To this end, ICG2 will use the impulsive radio-frequency
(RF) signal produced by neutrino interactions in polar ice caps. In
such experiments, rare single event candidates must be unambiguously
separated from background; to date, signal identification strategies
primarily reject thermal noise and anthropogenic backgrounds. Here,
we consider the possibility that fake neutrino signals may also
be naturally generated via the 'triboelectric effect'. This broadly
includes any process in which force applied at a boundary layer results
in displacement of surface charge, generating a potential difference
{\Delta}V. Wind blowing over granular surfaces such as snow can
induce such a {\Delta}V, with subsequent discharge. Discharges over
nanosecond-timescales can then lead to RF emissions at characteristic
MHz-GHz frequencies. We find that such backgrounds are evident
in the several neutrino experiments considered, and are generally
characterized by: a) a threshold wind velocity which likely depends
on the experimental signal trigger threshold and layout; for the
experiments considered herein, this value is typically O(10 m/s), b)
frequency spectra generally shifted to the low-end of the frequency
regime to which current radio experiments are typically sensitive
(100-200 MHz), c) for the strongest background signals, an apparent
preference for discharges from above-surface structures, although the
presence of more isotropic, lower amplitude triboelectric discharges
cannot be excluded.
Title: Unusual Near-Horizon Cosmic-Ray-like Events Observed by
ANITA-IV
Authors: Gorham, P. W.; Ludwig, A.; Deaconu, C.; Cao, P.; Allison,
P.; Banerjee, O.; Batten, L.; Bhattacharya, D.; Beatty, J. J.; Belov,
K.; Binns, W. R.; Bugaev, V.; Chen, C. H.; Chen, P.; Chen, Y.; Clem,
J. M.; Cremonesi, L.; Dailey, B.; Dowkontt, P. F.; Fox, B. D.; Gordon,
J. W. H.; Hast, C.; Hill, B.; Hsu, S. Y.; Huang, J. J.; Hughes, K.;
Hupe, R.; Israel, M. H.; Liu, T. C.; Macchiarulo, L.; Matsuno, S.;
McBride, K.; Miki, C.; Nam, J.; Naudet, C. J.; Nichol, R. J.; Novikov,
A.; Oberla, E.; Olmedo, M.; Prechelt, R.; Rauch, B. F.; Roberts,
J. M.; Romero-Wolf, A.; Rotter, B.; Russell, J. W.; Saltzberg, D.;
Seckel, D.; Schoorlemmer, H.; Shiao, J.; Stafford, S.; Stockham, J.;
Stockham, M.; Strutt, B.; Sutherland, M. S.; Varner, G. S.; Vieregg,
A. G.; Wang, S. H.; Wissel, S. A.
Bibcode: 2021PhRvL.126g1103G
Altcode:
ANITA's fourth long-duration balloon flight in 2016
detected 29 cosmic-ray (CR)-like events on a background of
0.37-0.17+0.27 anthropogenic events. CRs are
mainly seen in reflection off the Antarctic ice sheets, creating a
phase-inverted waveform polarity. However, four of the below-horizon
CR-like events show anomalous noninverted polarity, a p =5.3
×10-4 chance if due to background. All anomalous events are
from locations near the horizon; ANITA-IV observed no steeply upcoming
anomalous events similar to the two such events seen in prior flights.
Title: Solar Activity of the Past 100 Years Inferred From
10Be in Ice Cores—Implications for Long Term Solar
Activity Reconstructions
Authors: Zheng, Minjie; Adolphi, Florian; Sjolte, Jesper; Aldahan,
Ala; Possnert, Göran; Wu, Mousong; Chen, Peng; Muscheler, Raimund
Bibcode: 2021GeoRL..4890896Z
Altcode:
Differences between 10Be records from Greenland
and Antarctica over the last 100 years have led to different
conclusions about past changes in solar activity. The reasons for
this disagreement remain unresolved. We analyze a seasonally resolved
10Be record from a firn core (North Greenland Eemian
Ice Drilling [NEEM] ice core project) in Northwestern Greenland for
1887-2002. By comparing the NEEM data to 10Be data from the
NGRIP and Dye3 ice cores, we find that the Dye3 data after 1958 are
significantly lower. These low values lead to a normalization problem
in solar reconstructions when connecting 10Be variations
to modern observations. Excluding these data strongly reduces the
differences between solar reconstructions over the last 2,000 years
based on Greenland and Antarctic 10Be data. Furthermore,
10Be records from polar regions and group sunspot numbers do
not support a substantial increase in solar activity for the 1937-1950
period as proposed by previous extensions of the neutron monitor data.
Title: An automatic speed adaption neural network model for planetary
gearbox fault diagnosis
Authors: Chen, Peng; Li, Yu; Wang, Kesheng; Zuo, Ming J.
Bibcode: 2021Meas..17108784C
Altcode:
In real-world applications, fault detection and diagnosis of planetary
gearboxes are vital if it can be employed to avert catastrophic failure
consequences in rotating machinery. Fault diagnosis usually starts with
collecting vibration signals from rotating machinery. These vibration
signals are usually produced in non-stationary operating conditions
with time-varying loads and speeds, which makes fault diagnosis more
challenging. Signal processing methods are typically selected for
fault diagnosis to capture either time, frequency, or time-frequency
based diagnostic features from measured vibration signals. Yet,
it is usually a costly or time-consuming process and, sometimes,
heavily dependent on human expertise. Although current deep learning
algorithms offer an efficient and intelligent diagnostic strategy
for fault diagnosis, unfortunately, most of the reported algorithms
are basically only valid for the stationary operating conditions. To
address the challenges of non-stationary operating conditions, in
this paper, an Automatic Speed Adaption Neural Network (ASANN) model
within the incorporation of instantaneous rotating speed is proposed,
and it provides an end-to-end learning fashion with the guidance of
rotating speed information. With the incorporating of instantaneous
rotating speed information, the proposed ASANN model enables the
extraordinary capacity for planetary gearbox fault detection under
varying operational scenarios. The validity of the ASANN model is
verified by an experimental investigation of fault diagnosis in a
planetary gearbox.
Title: Accuracy analysis of GNSS-IR snow depth inversion algorithms
Authors: Li, Zheng; Chen, Peng; Zheng, Naiquan; Liu, Hang
Bibcode: 2021AdSpR..67.1317L
Altcode:
In recent years, with the continuous development of Global Navigation
Satellite System (GNSS), it has been applied not only to navigation
and positioning, but also to Earth surface environment monitoring. At
present, when performing GNSS-IR (GNSS Interferometric Reflectometry)
snow depth inversion, Lomb-Scargle Periodogram (LSP) spectrum analysis
is mainly used to calculate the vertical height from the antenna
phase center to the reflection surface. However, it has the problem
of low identification of power spectrum analysis, which may lead to
frequency leakage. Therefore, Fast Fourier Transform (FFT) spectrum
analysis and Nonlinear Least Square Fitting (NLSF) are introduced to
calculate the vertical height in this paper. The GNSS-IR snow depth
inversion experiment is carried out by using the observation data
of P351 station in PBO (Plate Boundary Observatory) network of the
United States from 2013 to 2016. Three algorithms are used to invert
the snow depth and compared with the actual snow depth provided by the
station 490 in the SNOTEL network. The observations data of L1 and L2
bands are respectively used to find the optimal combination between
different algorithms further to improve the accuracy of GNSS-IR snow
depth inversion. For L1 band, different snow depths correspond to
different optimal algorithms. When the snow depth is less than 0.8
m, the inversion accuracy of NLSF algorithm is the highest. When
the snow depth is greater than 0.8 m, the inversion accuracy of FFT
algorithm is higher. Therefore, according to the different snow depth,
a combined algorithm of NLSF + FFT is proposed for GNSS-IR snow depth
inversion. Compared with the traditional LSP algorithm, the inversion
accuracy of the combined algorithm is improved by 10%. For L2 band data,
the results show that the accuracy of snow depth inversion of various
algorithms do not change with the variations of snow depth. Among the
three single algorithms, the inversion accuracy of FFT algorithm is
better than that of LSP and NLSF algorithms.
Title: From Nonlinear Force-free Field Models to Data-driven
Magnetohydrodynamic Simulations
Authors: Guo, Yang; Chen, P. F.; Keppens, Rony; Xia, Chun; Ding,
Mingde; Yang, Kai; Zhong, Ze
Bibcode: 2021cosp...43E1777G
Altcode:
To study the origin, structures, and dynamics of various solar
activities, such as flares, prominences/filaments, and coronal
mass ejections, we have to know the 3D magnetic field in the solar
corona. Since many static phenomena in the corona live in a low
beta environment, they can be modelled as a force-free state. We
have implemented a new nonlinear force-free field (NLFFF) algorithm
in the Message Passing Interface Adaptive Mesh Refinement Versatile
Advection Code (MPI-AMRVAC), which could construct an NLFFF model in
both Cartesian and spherical coordinate systems, and in all uniform,
adaptive mesh refinement, and stretched grids. The NLFFF models
have been applied to observations to study the magnetic structures
of flux ropes, the coronal emission in extreme ultraviolet lines
and the morphology of flare ribbons. To further study the dynamic
eruption of a magnetic flux rope, we have developed a data-driven
magnetohydrodynamic (MHD) model using the zero-beta MHD equations. The
NLFFF model is served as the initial condition, and the time series
of observed magnetic field and velocity field provide the boundary
conditions. This model can reproduce the evolution of a magnetic flux
rope in its dynamic eruptive phase. We also find that a data-constrained
boundary condition, where the bottom boundary is fixed to the initial
values, reproduces a similar simulation result as the data-driven
simulation. The data-driven MHD model has also been applied to study
a failed eruption, where the torus instability, kink instability,
and additional components of Lorentz forces are studied in detail.
Title: End-to-end modeling of Lyot coronagraph for LUVOIR: sensitivity
to segment-level aberrations
Authors: Sirbu, D.; Juanola-Parramon, R.; Stark, C.; Belikov, R.;
Chen, P.; Riggs, A.; Ruane, G.
Bibcode: 2021AAS...23741603S
Altcode:
Direct imaging and spectroscopic characterization of atmospheres
of Earth-like exoplanets require starlight suppression to detect a
faint planetary signal at small angular separations. Future space
telescopes will require segmentation to survey a statistically
significant population of nearby stars systems by increasing aperture
size beyond the limits set by traditional monolithic apertures;
however, segmentation also represents an additional challenge due to
the introduction of temporal pupil discontinuities in terms of both
phase and amplitude. For this study, a baseline Lyot coronagraph is
used with the Large UV / Optical /Infrared (LUVOIR) mission's 15-m
on-axis, segmented optical telescope assembly (OTA). We present
a high-fidelity, end-to-end modeling approach developed as part
of the Segmented Coronagraph Design and Analysis (SCDA) group that
includes diffractive optical propagations at the 1e-10 contrast level
across the entire optical train including the OTA and intermediate
re-imaging optics inside the coronagraph instrument. We perform a
tolerancing analysis to assess the contrast sensitivity to wavefront
perturbations for a set of key telescope terms including segment-level
low-order and mid-spatial frequency aberrations. As an input to the
end-to-end telescope model, we use two industry-provided segment-level
wavefront aberration datasets pertaining: (1) thermal gradients
and accelerations (courtesy of Ball-Aerospace and L3-Harris), and
(2) telescope dynamics including line-of-sight and segment jitter
(courtesy of Lockheed-Martin). Contrast performance outputs of the
coronagraph are fed into a mission design reference simulator to assess
the scientific yield sensitivity. End-to-end modeling will incorporate
performance improvements due to active wavefront sensing and control
and/or segment-level metrology to improve system performance.
Title: Two controversial issues related to magnetic flux ropes
Authors: Chen, P. F.
Bibcode: 2021cosp...43E1740C
Altcode:
Magnetic flux ropes play a vital role in solar and presumably stellar
eruptions since they represent a typical kind of nonpotential magnetic
configurations which can power solar eruptions, as well as eruptions
in other astrophysical objects. While flux ropes have attracted
wide attention in the solar community during the past decades, there
are several controversial issues and associated misunderstanding in
the literature. In this talk, I discuss two of them. The first one
is about whether magnetic flux ropes are formed during eruption or
before eruption. While most colleagues claim that flux ropes always
exist before eruptions, their proofing is vague since it is not
appropriate to claim the universality based on limited samples. With
our novel method applied to a large sample of events, we found that
about 89% of filament eruptions are associated with pre-existing
flux ropes. The other issue is about the signature of flux ropes in
coronagraph observations. Flux ropes have been widely used to fit the
frontal loops of the observed coronal mass ejections. In this talk,
I will show why it might not be correct.
Title: Soft X-ray Coronagraph on-board ChinesE Space Station (SXCCESS)
Authors: Chen, P. F.; Cheng, Xin; Guo, Yang; Li, Zhiyuan; Li, Chuan
Bibcode: 2021cosp...43E.792C
Altcode:
The solar corona is rich of fine structures, such as coronal holes and
polar plumes at high latitudes, and active regions and streamers at
low latitudes. More importantly, solar flares, coronal mass ejections
(CMEs), and many other types of solar eruptions occur frequently in
the corona. The observations of the solar corona can greatly enhance
our understanding on these eruptive phenomena and advance the research
related to interplanetary space. Meanwhile, the enduring observations
can capture some rare phenomena, such as the interaction between
comets and the solar wind or between comets and interplanetary
CMEs. This type of observations can deepen our knowledge of the
solar wind abundance and charge states, the chemical composition of
comets. Nanjing University, Beijing Institute of Space Mechanics and
Electronics, and China Building Materials Academy jointly propose
to develop a Soft X-ray Coronagraph on-board ChinesE Space Station
(SXCCESS), in order to conduct unprecedented imaging spectroscopic
X-ray observations of the solar corona. With the lobster-eye technique,
the telescope can perform imaging spectroscopic observations with a
field of view of 1-15 solar radii and a waveband of 0.2-7 keV, which
will be a milestone in solar space observations. SXCCESS will provide
unprecedented unique data for the solar and space physics communities,
and help understanding the trigger/acceleration mechanisms of CMEs and
the physics of magnetic reconnection. These observations can also offer
space weather forecast for the space environment of the Space Station.
Title: The magnetic flux rope structure of a triangulated solar
filament
Authors: Guo, Yang; Chen, P. F.; Keppens, Rony; Xia, Chun; Ding,
Mingde; Xu, Yu
Bibcode: 2021cosp...43E1734G
Altcode:
We construct a magnetic flux rope model for a prominence observed at
01:11 UT on 2011 June 21 in AR 11236 using the following methods,
triangulation from multi perspective observations, the flux
rope embedding method, the regularized Biot-Savart laws, and the
magnetofrictional method. First, the prominence path is reconstructed
with the triangulation with 304 Å images observed by the Atmospheric
Imaging Assembly on board Solar Dynamics Observatory (SDO) and by the
Extreme Ultraviolet Imager on board the twin Solar Terrestrial Relations
Observatory. Then, a flux rope is constructed with the regularized
Biot-Savart laws using the information of its axis. Next, it is embedded
into a potential magnetic field computed from the photospheric radial
magnetic field observed by the Helioseismic and Magnetic Imager on
board SDO. The combined magnetic field is finally relaxed by the
magnetofrictional method to reach a nonlinear force-free state. It
is found that both models constructed by the regularized Biot-Savart
laws and after the magnetofrictional relaxation coincide with the
304 Å images. The distribution of magnetic dips coincides with part
of the prominence material, and the quasi-separatrix layers wrap the
magnetic flux ropes, displaying hyperbolic flux tube structures. These
models have the advantages of constructing magnetic flux ropes in the
higher atmosphere and weak magnetic field regions, which could be used
as initial conditions for magnetohydrodynamic simulations of coronal
mass ejections.
Title: Discovery and follow-up of ASASSN-19dj: an X-ray and UV
luminous TDE in an extreme post-starburst galaxy
Authors: Hinkle, Jason T.; Holoien, T. W. -S.; Auchettl, K.; Shappee,
B. J.; Neustadt, J. M. M.; Payne, A. V.; Brown, J. S.; Kochanek,
C. S.; Stanek, K. Z.; Graham, M. J.; Tucker, M. A.; Do, A.; Anderson,
J. P.; Bose, S.; Chen, P.; Coulter, D. A.; Dimitriadis, G.; Dong, Subo;
Foley, R. J.; Huber, M. E.; Hung, T.; Kilpatrick, C. D.; Pignata, G.;
Piro, A. L.; Rojas-Bravo, C.; Siebert, M. R.; Stalder, B.; Thompson,
Todd A.; Tonry, J. L.; Vallely, P. J.; Wisniewski, J. P.
Bibcode: 2021MNRAS.500.1673H
Altcode: 2020arXiv200606690H; 2020MNRAS.tmp.2967H; 2020MNRAS.500.1673H
We present observations of ASASSN-19dj, a nearby tidal disruption event
(TDE) discovered in the post-starburst galaxy KUG 0810+227 by the
All-Sky Automated Survey for Supernovae (ASAS-SN) at a distance of d
≃ 98 Mpc. We observed ASASSN-19dj from -21 to 392 d relative to peak
ultraviolet (UV)/optical emission using high-cadence, multiwavelength
spectroscopy and photometry. From the ASAS-SN g-band data, we
determine that the TDE began to brighten on 2019 February 6.8 and for
the first 16 d the rise was consistent with a flux ∝t2
power law. ASASSN-19dj peaked in the UV/optical on 2019 March 6.5
(MJD = 58548.5) at a bolometric luminosity of L = (6.2 ± 0.2)
× 1044 erg s-1. Initially remaining roughly
constant in X-rays and slowly fading in the UV/optical, the X-ray flux
increased by over an order of magnitude ~225 d after peak, resulting
from the expansion of the X-ray emitting region. The late-time X-ray
emission is well fitted by a blackbody with an effective radius of ~1
× 1012 cm and a temperature of ~6 × 105 K. The
X-ray hardness ratio becomes softer after brightening and then returns
to a harder state as the X-rays fade. Analysis of Catalina Real-Time
Transient Survey images reveals a nuclear outburst roughly 14.5 yr
earlier with a smooth decline and a luminosity of LV ≥ 1.4
× 1043 erg s-1, although the nature of the flare
is unknown. ASASSN-19dj occurred in the most extreme post-starburst
galaxy yet to host a TDE, with Lick HδA = 7.67 ± 0.17 Å.
Title: Modeling Subsurface Origins and Transport of Methane on Mars
Authors: Luo, Y.; Klusman, R. W.; Chen, P.; Yung, Y. L.
Bibcode: 2020AGUFMP058...05L
Altcode:
Methane has been detected in the Martian atmosphere by both remote
sensing and in situ measurements. A variety of subsurface methane
production mechanisms have been proposed, such as (1) abiotic
synthesis associated with water-rock reactions in the Martian crust,
(2) breakdown of organic matter in Martian soils and crust, and
(3) biotic formation through a metabolic process. Following methane
production, there are also a variety of transport mechanisms that
can bring methane to the surface. The six methane spikes detected
by the Tunable Laser Spectrometer, on board the Curiosity rover in
Gale crater, suggest that a pulse transport mechanism is at work. One
possible mechanism is as follows. The transport of methane from the
warmer subterranean region to the surface can also include transport of
water vapor, brine water and dissolved minerals. Closer to the surface
where temperatures are lower, ice can form and minerals precipitate,
sequestering methane in the form of clathrate, adsorbed on minerals or
trapped as gas bubbles in ice. In spring, when the temperatures on Mars
return to warmer values, some of the ice collapses or partially melts,
releasing methane into the atmosphere. If the methane emission site is
close to the detector, a pulse emission event will result in a methane
spike. In this study, we model this subsurface transport mechanism,
and explore what characteristics of the source can be preserved at
the surface that can be used to constrain the origin of methane,
such as the chemical compositions o f the released gas plume, e.g.,
H2 and C2H6. The results from this
study will help future Mars missions design their observational
techniques and strategies.
Title: ASAS-SN Transient Classification Report for 2020-12-08
Authors: Chen, P.; Bose, S.; Dong, S.; Klusmeyer, J.; Shields, J.;
Stanek, K. Z.
Bibcode: 2020TNSCR3710....1C
Altcode:
No abstract at ADS
Title: ASAS-SN Transient Classification Report for 2020-12-23
Authors: Chen, P.; Bose, S.; Holoien, T. W. S.; Dong, S.
Bibcode: 2020TNSCR3900....1C
Altcode:
No abstract at ADS
Title: Long-baseline horizontal radio-frequency transmission through
polar ice
Authors: Allison, P.; Archambault, S.; Beatty, J. J.; Besson, D. Z.;
Chen, C. C.; Chen, C. H.; Chen, P.; Christenson, A.; Clark, B. A.;
Clay, W.; Connolly, A.; Cremonesi, L.; Deaconu, C.; Duvernois, M.;
Friedman, L.; Gaior, R.; Hanson, J.; Hanson, K.; Haugen, J.; Hoffman,
K. D.; Hong, E.; Hornhuber, C.; Hsu, S. Y.; Hu, L.; Huang, J. J.;
Huang, M. -H. A.; Hughes, K.; Ishihara, A.; Karle, A.; Kelley, J. L.;
Khandelwal, R.; Kim, M. -C.; Kravchenko, I.; Kruse, J.; Kurusu, K.;
Kuwabara, T.; Latif, U. A.; Laundrie, A.; Li, C. -J.; Liu, T. -C.; Lu,
M. -Y. -; Madison, B.; Mase, K.; Meures, T.; Nam, J.; Nichols, R. J.;
Novikov, A.; Nozdrina, A.; Oberla, E.; Pan, Y.; Pfendner, C.; Relich,
M.; Sandstrom, P.; Seckel, D.; Shiao, Y. S.; Shultz, A.; Smith, D.;
Song, M.; Torres, J.; Touart, J.; Varner, G. S.; Vieregg, A.; Wang,
M. Z.; Wang, S. H.; Wissel, S.; Yoshida, S.; Young, R.; Jordan, T.
Bibcode: 2020JCAP...12..009A
Altcode: 2019arXiv190810689A
We report on analysis of englacial radio-frequency (RF) pulser data
received over horizontal baselines of 1-5 km, based on broadcasts from
two sets of transmitters deployed to depths of up to 1500 meters at
the South Pole. First, we analyze data collected using two RF bicone
transmitters 1400 meters below the ice surface, and frozen into
boreholes drilled for the IceCube experiment in 2011. Additionally,
in Dec., 2018, a fat-dipole antenna, fed by one of three high-voltage
(Script O(1 kV)), fast (Script O(1-5 ns risetime)) signal generators
was lowered into the 1700-m deep icehole drilled for the South Pole Ice
Core Experiment (SPICE), approximately 3 km from the geographic South
Pole. Signals from transmitters were recorded on the five englacial
multi-receiver ARA stations, with receiver depths between 60-200
m. From analysis of deep transmitter data, we estimate: i) the range
of refractive index profiles of Antarctic ice with depth allowed
by our measurements, ii) due to birefringence, a time difference
between arrival times for vertically polarized vs. horizontally
polarized signals (per km) for horizontally propagating signal, and
iii) for the first time, the attenuation length for electromagnetic
signals in the radio-frequency regime broadcast horizontally (rather
than reflected vertically from bedrock). We additionally present
data suggesting anomalous ice propagation effects, and contrary to
expectations for a transport medium with a smoothly varying refractive
index profile. Our results imply negligible uncertainty in overall
neutrino detection volume due to refractive index uncertainties. Our
birefringence time-difference measurements are fit to the functional
form δt(H-V) [ns/km]=acosθ+b, with H/V the signal arrival
times for the horizontally/vertically polarized EM signal components,
and θ the opening angle in the horizontal plane between the signal
propagation direction and the local ice flow direction, extracting
a=8.3±1.3 ns/km, and b=-8.6±0.9 ns/km (errors combined statistical
and systematic), allowing a ~15% range estimate for future measurements
of in-ice neutrino interactions. Finally, we find attenuation length
values clustering around 1.5 km, with measurements from the bicone
transmitters yielding Latten=1.43±0.25±0.37 km. Taken
together, these measurements support cold polar ice as a near-optimal
platform for ultra-high energy neutrino detectors.
Title: The design of the Ali CMB Polarization Telescope receiver
Authors: Salatino, M.; Austermann, J.; Thompson, K. L.; Ade, P. A. R.;
Bai, X.; Beall, J. A.; Becker, D. T.; Cai, Y.; Chang, Z.; Chen, D.;
Connors, J.; Chen, P.; Dober, B.; Delabrouille, J.; Duff, S. M.; Gao,
G.; Givhan, R. C.; Ghosh, S.; Hilton, G.; Hu, B.; Hubmayr, J.; Karpel,
E.; Kuo, C. -L.; Li, H.; Li, M.; Li, S. -Y.; Li, X.; Link, M.; Li, Y.;
Liu, H.; Liu, L.; Liu, Y.; Lu, F.; Lukas, T.; Lu, X.; Mates, J. A. B.;
Mathewson, J.; Mauskopf, P.; Meinke, J.; Montana-Lopez, J.; Moore,
J.; Shi, J.; Sinclair, A. K.; Stephenson, R.; Sun, W.; Tseng, Y. -H.;
Tucker, C.; Ullom, J.; Vale, L.; van Lanen, J.; Vissers, M.; Walker,
S.; Wang, B.; Wang, G.; Wang, J.; Weeks, E.; Wu, Di; Wu, Y. -H.; Xia,
J.; Xu, H.; Yao, J.; Yao, Y.; Yoon, K. W.; Yue, B.; Zhai, H.; Zhang,
A.; Zhang, Laiyu; Zhang, Le; Zhang, P.; Zhang, T.; Zhang, Xinmin;
Zhang, Yifei; Zhang, Yongjie; Zhao, G. -B.; Zhao, W.
Bibcode: 2020SPIE11453E..2AS
Altcode: 2021arXiv210109608S
AliCPT-1 is the first CMB degree scale polarimeter to be deployed to the
Tibetan plateau at 5,250m asl. AliCPT-1 is a 95/150GHz 72cm aperture,
two lens refracting telescope cooled down to 4K. Alumina lenses image
the CMB on a 636mm wide focal plane. The modularized focal plane
consists of dichroic polarization-sensitive Transition-Edge Sensors
(TESes). Each module includes 1,704 optically active TESes fabricated
on a 6in Silicon wafer. Each TES array is read out with a microwave
multiplexing with a multiplexing factor up to 2,000. Such large factor
has allowed to consider 10's of thousands of detectors in a practical
way, enabling to design a receiver that can operate up to 19 TES arrays
for a total of 32,300 TESes. AliCPT-1 leverages the technological
advancements of AdvACT and BICEP-3. The cryostat receiver is currently
under integration and testing. Here we present the AliCPT-1 receiver,
underlying how the optimized design meets the experimental requirements.
Title: Transient Classification Report for 2020-12-08
Authors: Chen, P.; Dong, S.; Bose, S.; Gromadzki, M.; Buckley, D. A. H.
Bibcode: 2020TNSCR3716....1C
Altcode:
No abstract at ADS
Title: Large-Scale Vortex Motion and Multiple Plasmoid Ejection Due
to Twisting Prominence Threads and Associated Reconnection
Authors: Mishra, Sudheer K.; Srivastava, A. K.; Chen, P. F.
Bibcode: 2020SoPh..295..167M
Altcode: 2020arXiv201102950M
We analyze the characteristics of a quiescent polar prominence using
the Atmospheric Imaging Assembly (AIA) onboard the Solar Dynamics
Observatory (SDO). Initially, small-scale barb-like structures are
evident on the solar disk, which firstly grow vertically and thereafter
move towards the south-west limb. Later, a spine connects these barbs
and we observe apparent rotating motions in the upper part of the
prominence. These apparent rotating motions might play an important
role for the evolution and growth of the filament by transferring cool
plasma and magnetic twist. Large-scale vortex motion is evident in the
upper part of the prominence and consists of a swirl-like structure
within it. The slow motion of the footpoint twists the legs of the
prominence due to magnetic shear, causing two different kinds of
magnetic reconnection. The internal reconnection is initiated by a
resistive-tearing-mode instability, which leads to the formation of
multiple plasmoids in the elongated current sheet. The estimated growth
rate was found to be 0.02 - 0.05. The magnetic reconnection heats
the current sheet for a small duration. However, most of the energy
release due to magnetic reconnection is absorbed by the surrounding
cool and dense plasma and used to accelerate the plasmoid ejection. The
multiple plasmoid ejections destroy the current sheet. Thereafter, the
magnetic arcades collapse near the X-point. Oppositely directed magnetic
arcades may reconnect with the southern segment of the prominence and
an elongated thin current sheet is formed. This external reconnection
drives the prominence eruption.
Title: Transient Classification Report for 2020-12-08
Authors: Chen, P.; Morrell, N.; Dong, S.; Bose, S.; Holoien, T. W. S.
Bibcode: 2020TNSCR3715....1C
Altcode:
No abstract at ADS
Title: Transient Classification Report for 2020-12-08
Authors: Chen, P.; Morrell, N.; Dong, S.; Kollmeier, J. A.
Bibcode: 2020TNSCR3714....1C
Altcode:
No abstract at ADS
Title: h5py/h5py: 3.1.0
Authors: Collette, Andrew; Kluyver, Thomas; Caswell, Thomas A;
Tocknell, James; Kieffer, Jerome; Scopatz, Anthony; Dale, Darren;
Chen; Jelenak, Aleksandar; payno; juliagarriga; VINCENT, Thomas;
Sciarelli, Pierlauro; Valls, Valentin; Kofoed Pedersen, Ulrik;
jakirkham; Raspaud, Martin; Parsons, Aaron; Abbasi, Hameer; Readey,
John; Paramonov, Andrey; Chan, Lawrence; jialin; Danilevski, Cyril;
Feng, Yu; Vaillant, Ghislain Antony; Teichmann, Martin; Brucher,
Matthieu; Johnson, Seth R.; Hole, Laurence
Bibcode: 2020zndo...4250762C
Altcode:
HDF5 for Python -- The h5py package is a Pythonic interface to the
HDF5 binary data format.
Title: SN 2017ivv: two years of evolution of a transitional Type
II supernova
Authors: Gutiérrez, C. P.; Pastorello, A.; Jerkstrand, A.; Galbany,
L.; Sullivan, M.; Anderson, J. P.; Taubenberger, S.; Kuncarayakti, H.;
González-Gaitán, S.; Wiseman, P.; Inserra, C.; Fraser, M.; Maguire,
K.; Smartt, S.; Müller-Bravo, T. E.; Arcavi, I.; Benetti, S.; Bersier,
D.; Bose, S.; Bostroem, K. A.; Burke, J.; Chen, P.; Chen, T. -W.;
Della Valle, M.; Dong, Subo; Gal-Yam, A.; Gromadzki, M.; Hiramatsu,
D.; Holoien, T. W. -S.; Hosseinzadeh, G.; Howell, D. A.; Kankare, E.;
Kochanek, C. S.; McCully, C.; Nicholl, M.; Pignata, G.; Prieto, J. L.;
Shappee, B.; Taggart, K.; Tomasella, L.; Valenti, S.; Young, D. R.
Bibcode: 2020MNRAS.499..974G
Altcode: 2020arXiv200809628G; 2020MNRAS.tmp.2720G
We present the photometric and spectroscopic evolution of the Type II
supernova (SN II) SN 2017ivv (also known as ASASSN-17qp). Located in an
extremely faint galaxy (Mr = -10.3 mag), SN 2017ivv shows an
unprecedented evolution during the 2 yr of observations. At early times,
the light curve shows a fast rise (~6-8 d) to a peak of ${\it M}^{\rm
max}_{g}= -17.84$ mag, followed by a very rapid decline of 7.94 ± 0.48
mag per 100 d in the V band. The extensive photometric coverage at late
phases shows that the radioactive tail has two slopes, one steeper than
that expected from the decay of 56Co (between 100 and 350 d),
and another slower (after 450 d), probably produced by an additional
energy source. From the bolometric light curve, we estimated that the
amount of ejected 56Ni is ~0.059 ± 0.003 M⊙. The nebular
spectra of SN 2017ivv show a remarkable transformation that allows
the evolution to be split into three phases: (1) Hα strong phase
(<200 d); (2) Hα weak phase (between 200 and 350 d); and (3) Hα
broad phase (>500 d). We find that the nebular analysis favours a
binary progenitor and an asymmetric explosion. Finally, comparing the
nebular spectra of SN 2017ivv to models suggests a progenitor with a
zero-age main-sequence mass of 15-17 M⊙.
Title: Some interesting topics provoked by the solar filament research
in the past decade
Authors: Chen, Peng-Fei; Xu, Ao-Ao; Ding, Ming-De
Bibcode: 2020RAA....20..166C
Altcode: 2020arXiv201002462C
Solar filaments are an intriguing phenomenon, like cool clouds suspended
in the hot corona. Similar structures exist in the intergalactic
medium as well. Despite being a long-studied topic, solar filaments
have continually attracted intensive attention because of their link
to coronal heating, coronal seismology, solar flares and coronal mass
ejections (CMEs). In this review paper, by combing through the solar
filament-related work done in the past decade, we discuss several
controversial topics, such as the fine structures, dynamics, magnetic
configurations and helicity of filaments. With high-resolution and
high-sensitivity observations, combined with numerical simulations,
it is expected that resolving these disputes will definitely lead to
a huge leap in understanding the physics related to solar filaments,
and even shed light on galactic filaments.
Title: Constraints on the diffuse flux of ultrahigh energy neutrinos
from four years of Askaryan Radio Array data in two stations
Authors: Allison, P.; Archambault, S.; Beatty, J. J.; Beheler-Amass,
M.; Besson, D. Z.; Beydler, M.; Chen, C. C.; Chen, C. H.; Chen, P.;
Clark, B. A.; Clay, W.; Connolly, A.; Cremonesi, L.; Davies, J.; de
Kockere, S.; de Vries, K. D.; Deaconu, C.; DuVernois, M. A.; Friedman,
E.; Gaior, R.; Hanson, J.; Hanson, K.; Hoffman, K. D.; Hokanson-Fasig,
B.; Hong, E.; Hsu, S. Y.; Hu, L.; Huang, J. J.; Huang, M. -H.; Hughes,
K.; Ishihara, A.; Karle, A.; Kelley, J. L.; Khandelwal, R.; Kim,
K. -C.; Kim, M. -C.; Kravchenko, I.; Kurusu, K.; Landsman, H.; Latif,
U. A.; Laundrie, A.; Li, C. -J.; Liu, T. -C.; Lu, M. -Y.; Madison,
B.; Mase, K.; Meures, T.; Nam, J.; Nichol, R. J.; Nir, G.; Novikov,
A.; Nozdrina, A.; Oberla, E.; O'Murchadha, A.; Osborn, J.; Pan, Y.;
Pfendner, C.; Roth, J.; Sandstrom, P.; Seckel, D.; Shiao, Y. -S.;
Shultz, A.; Smith, D.; Torres, J.; Touart, J.; van Eijndhoven, N.;
Varner, G. S.; Vieregg, A. G.; Wang, M. -Z.; Wang, S. -H.; Wissel,
S. A.; Yoshida, S.; Young, R.; ARA Collaboration
Bibcode: 2020PhRvD.102d3021A
Altcode:
The Askaryan Radio Array (ARA) is an ultrahigh energy (UHE,
>1017 eV ) neutrino detector designed to observe neutrinos
by searching for the radio waves emitted by the relativistic products
of neutrino-nucleon interactions in Antarctic ice. In this paper, we
present constraints on the diffuse flux of ultrahigh energy neutrinos
between 1016 and 1021 eV resulting from a search
for neutrinos in two complementary analyses, both analyzing four years
of data (2013-2016) from the two deep stations (A2, A3) operating at
that time. We place a 90% CL upper limit on the diffuse all flavor
neutrino flux at 1018 eV of E F (E )=5.6 ×10-16
cm-2 s-1 sr-1 . This analysis includes
four times the exposure of the previous ARA result and represents
approximately 1 /5 th the exposure expected from operating ARA until
the end of 2022.
Title: Unusual Near-horizon Cosmic-ray-like Events Observed by
ANITA-IV
Authors: ANITA Collaboration; Gorham, P. W.; Ludwig, A.; Deaconu,
C.; Cao, P.; Allison, P.; Banerjee, O.; Batten, L.; Bhattacharya, D.;
Beatty, J. J.; Belov, K.; Binns, W. R.; Bugaev, V.; Chen, C. H.; Chen,
P.; Chen, Y.; Clem, J. M.; Cremonesi, L.; Dailey, B.; Dowkontt, P. F.;
Fox, B. D.; Gordon, J. W. H.; Hast, C.; Hill, B.; Hsu, S. Y.; Huang,
J. J.; Hughes, K.; Hupe, R.; Israel, M. H.; Liu, T. C.; Macchiarulo,
L.; Matsuno, S.; McBride, K.; Miki, C.; Nam, J.; Naudet, C. J.;
Nichol, R. J.; Novikov, A.; Oberla, E.; Olmedo, M.; Prechelt, R.;
Prohira, S.; Rauch, B. F.; Roberts, J. M.; Romero-Wolf, A.; Rotter,
B.; Russell, J. W.; Saltzberg, D.; Seckel, D.; Schoorlemmer, H.; Shiao,
J.; Stafford, S.; Stockham, J.; Stockham, M.; Strutt, B.; Sutherland,
M. S.; Varner, G. S.; Vieregg, A. G.; Wang, S. H.; Wissel, S. A.
Bibcode: 2020arXiv200805690A
Altcode:
ANITA's fourth long-duration balloon flight in late 2016 detected 29
cosmic-ray (CR)-like events on a background of $0.37^{+0.27}_{-0.17}$
anthropogenic events. CRs are mainly seen in reflection off the
Antarctic ice sheets, creating a characteristic phase-inverted waveform
polarity. However, four of the below-horizon CR-like events show
anomalous non-inverted polarity, a $p = 5.3 \times 10^{-4}$ chance
if due to background. All anomalous events are from locations near
the horizon; ANITA-IV observed no steeply-upcoming anomalous events
similar to the two such events seen in prior flights.
Title: VizieR Online Data Catalog: NUV to NIR photometry of type
IIP ASASSN-16at (Bose+, 2019)
Authors: Bose, S.; Dong, S.; Elias-Rosa, N.; Shappee, B. J.;
Bersier, D.; Benetti, S.; Stritzinger, M. D.; Grupe, D.; Kochanek,
C. S.; Prieto, J. L.; Chen, P.; Kuncarayakti, H.; Mattila, S.;
Morales-Garoffolo, A.; Morrell, N.; Onori, F.; Reynolds, T. M.;
Siviero, A.; Somero, A.; Stanek, K. Z.; Terreran, G.; Thompson, T. A.;
Tomasella, L.; Ashall, C.; Gall, C.; Gromadzki, M.; Holoien, T. W. -S.
Bibcode: 2020yCat..18739003B
Altcode:
ASASSN-16at was discovered in the host galaxy UGC 8041 by the All-Sky
Automated Survey for Supernovae (ASAS-SN; Shappee+ 2014, J/ApJ/788/48)
on UT 2016 January 20.59 using the "Brutus" telescope in Haleakala,
Hawaii. The host galaxy distance is 15.2+/-3.0Mpc according to
Sorce+ (2014, J/MNRAS/444/527). We adopt the explosion epoch of 2016
January 18.92 (JD 2457406.42+/-0.57) and use this as the reference
epoch. We obtained NUV through near-IR (NIR) photometry and
optical spectroscopy of ASASSN-16at from 0.6 to 881 days. The NUV
observations were obtained with the Neil-Gehrels-Swift-Observatory
Ultraviolet/Optical Telescope (UVOT). Optical photometric observations
were obtained using the ASAS-SN quadruple 14cm "Brutus" telescopes,
the 2.0m Liverpool telescope (LT), the Las Cumbres Observatory 1.0m
telescope network. NIR observations were obtained with the 2.6m
Nordic Optical Telescope (NOT). Spectroscopic observations were
done using the ALFOSC the 2.6m NOT, the B&C spectrograph on the
1.2m Galileo Telescope, the AFOSC spectrograph on the 1.8m Copernico
telescope in Asiago (Italy), the SPRAT spectrograph mounted on LT,
the B&C Spectrograph on the 2.5m Irenee du Pont, LDSS on the 6.5m
Magellan Baade telescope, LRS on the 3.6m Telescopio Nazionale Galileo
and the OSIRIS spectrograph on 10.4m Gran Telescopio Canarias (GTC)
between 2016 Jan 21 and 2018 Jan 28. (2 data files).
Title: Solar and climate signals revealed by seasonal 10Be
data from the NEEM ice core project for the neutron monitor period
Authors: Zheng, Minjie; Adolphi, Florian; Sjolte, Jesper; Aldahan,
Ala; Possnert, Göran; Wu, Mousong; Chen, Peng; Muscheler, Raimund
Bibcode: 2020E&PSL.54116273Z
Altcode:
10Be in ice cores has been instrumental for reconstructing
past changes in solar activity prior to direct observations. For
a robust use of these records, it is pivotal to understand the
10Be transport and deposition. However, there are only
few high-resolution seasonal 10Be data longer than one
full solar cycle (11 years) that could enable a quantification of
the influences of atmospheric circulation and deposition processes
on the 10Be signal in ice. Here we present a seasonally
resolved 10Be data set covering the neutron monitor period
(1951-2002) from a firn core connected to the NEEM (North Greenland
Eemian Ice Drilling) project. The results suggest that both summer
and winter 10Be reflect the production signal induced
by solar modulation of galactic cosmic rays. However, superimposed
on this solar signal we find additional meteorologically driven
influences on 10Be transport and deposition. We found that
the tropopause pressure over 30°N represents an important factor
influencing NEEM 10Be concentrations on seasonal and
annual scales. 10Be deposited in summer also correlates
significantly with the tropopause pressure over Greenland suggesting
a direct contribution of stratospheric intrusions during summer to
the 10Be deposition in Greenland. To correct for these
transport/deposition influences, we apply a first-order correction to
the 10Be data using a multi-linear regression model. The
"climate-corrected" 10Be data shows a comparable skill
for reconstructing production rate changes as the 10Be
composite record from five different ice cores in Greenland. The
results suggest that the correction approach can be a complementary
method to the stacking to better isolate the production rate signal
from the 10Be data when only limited data are available.
Title: ASO-S Specical Issue in Chinese: Preface
Authors: Huang, Y.; Chen, P. F.; Gan, W. Q.
Bibcode: 2020AcASn..61...32H
Altcode:
The Advanced Space-based Solar Observatory (ASO-S) is the first approved
solar space mission in China. This special issue includes a total
of 14 papers, which focus on some important details of the satellite
platform and payload. These 14 papers and the 13 papers of RAA special
issue provide a complete description of ASO-S, including the design
and development of scientific instruments and data analysis methods.
Title: SALT spectroscopic follow-up of the bright type Ia SN AT2020nvb
Authors: Aydi, E.; Buckley, D. A. H.; Dong, S.; Chen, P.; Chomiuk,
L.; Kochanek, C. S.; Stanek, K. Z.
Bibcode: 2020ATel13858....1A
Altcode:
We report on high-resolution optical spectroscopy of the bright type
Ia SN AT2020nvb in NGC 4457, which was discovered by Koichi Itagaki
on 2020-07-1.55UT (see classification ATels #13848, #13849 and ASAS-SN
light curve).
Title: VizieR Online Data Catalog: ASAS-SN bright supernova catalogue
2016 (Holoien+, 2017)
Authors: Holoien, T. W. -S.; Brown, J. S.; Stanek, K. Z.; Kochanek,
C. S.; Shappee, B. J.; Prieto, J. L.; Dong, S.; Brimacombe, J.; Bishop,
D. W.; Bose, S.; Beacom, J. F.; Bersier, D.; Chen, P.; Chomiuk, L.;
Falco, E.; Godoy-Rivera, D.; Morrell, N.; Pojmanski, G.; Shields,
J. V.; Strader, J.; Stritzinger, M. D.; Thompson, T. A.; Wozniak,
P. R.; Bock, G.; Cacella, P.; Conseil, E.; Cruz, I.; Fernandez, J. M.;
Kiyota, S.; Koff, R. A.; Krannich, G.; Marples, P.; Masi, G.; Monard,
L. A. G.; Nicholls, B.; Nicolas, J.; Post, R. S.; Stone, G.; Wiethoff,
W. S.
Bibcode: 2020yCat..74714966H
Altcode:
Table 1 includes information for all SNe discovered by ASAS-SN between
2016 January 1 and 2016 December 31. As in Holoien et al. (2017,
Cat.J/MNRAS/464/2672 and Cat. J/MNRAS/467/1098), all names, discovery
dates and host names are taken from our discovery ATels, all of which
are cited in Table 1. We also include the SN names designated by
TNS, the official International Astronomical Union (IAU) mechanism
for reporting new astronomical transients. In Table 2, we
give information for all spectroscopically confirmed SNe with peak
magnitudes of mpeak<=17 that were discovered by other
professional and amateur SN searches between 2016 January 1 and 2016
December 31. For the host galaxies of both SN samples, we collected
Galactic extinction estimates for the direction to the host and host
magnitudes spanning from the near-ultraviolet (NUV) to the infrared
(IR) wavelengths. We present these data in Tables 3 and 4 for ASAS-SN
hosts and non-ASAS-SN hosts, respectively. (5 data files).
Title: Chirality and magnetic configuration associated with two-ribbon
solar flares: AR 10930 versus AR 11158
Authors: He, Han; Wang, Huaning; Yan, Yihua; Li, Bo; Chen, P. F.
Bibcode: 2020AdSpR..65.2828H
Altcode: 2018arXiv181013124H
The structural property of the magnetic field in flare-bearing solar
active regions (ARs) is one of the key aspects for understanding and
forecasting solar flares. In this paper, we make a comparative analysis
on the chirality and magnetic configurations associated with two X-class
two-ribbon flares happening in AR 10930 and AR 11158. The photospheric
magnetic fields of the two ARs were observed by space-based instruments,
and the corresponding coronal magnetic fields were calculated based
on the nonlinear force-free field model. The analysis shows that
the electric current in the two ARs was distributed mostly around
the main polarity inversion lines (PILs) where the flares happened,
and the magnetic chirality (indicated by the signs of force-free
factor α) along the main PILs is opposite for the two ARs, i.e.,
left-handed (α < 0) for AR 10930 and right-handed (α > 0)
for AR 11158. It is found that, for both the flare events, a prominent
magnetic connectivity (featured by co-localized strong α and strong
current density distributions) was formed along the main PIL before
flare and was totally broken after flare eruption. The two branches
of the broken magnetic connectivity, combined with the prominent
magnetic connectivity before flare, compose the opposite magnetic
configurations in the two ARs owing to their opposite chirality,
i.e., Z-shaped configuration in AR 10930 with left-handed chirality
and inverse Z-shaped configuration in AR 11158 with right-handed
chirality. It is speculated that two-ribbon flares can be generally
classified to these two magnetic configurations by chirality in the
flare source regions of ARs.
Title: VizieR Online Data Catalog: CO obs. of Planck Galactic cold
clumps (Zhang+, 2020)
Authors: Zhang, C.; Wu, Y.; Liu, X.; Qin, S. -L.; Liu, T.; Yuan, J.;
Li, D.; Meng, F.; Zhang, T.; Tang, M.; Yuan, L.; Zhou, C.; Esimbek,
J.; Zhou, Y.; Chen, P.; Hu, R.
Bibcode: 2020yCat..22470029Z
Altcode:
The sample in this paper is a subset of 674 Planck Galactic cold
clumps (PGCCs) observed by Wu+ (2012 J/ApJ/756/76) located in the
first quadrant (IQuad) and the anticenter direction region (ACent),
selected from the Early Cold Cores (ECC) catalog (Planck Collaboration,
2011, VIII/88). Observations of the 65 IQuad PGCCs and 39 ACent
PGCCs were carried out with the 13.7m millimeter-wavelength telescope
of the Purple Mountain Observatory (PMO) in the J=1-0 transition of
12CO, 13CO, and C18O from 2011 April
to May and from 2011 December to 2012 January. (5 data files).
Title: Simulations of solar filament fine structures and their
counterstreaming flows
Authors: Zhou, Y. H.; Chen, P. F.; Hong, J.; Fang, C.
Bibcode: 2020NatAs...4..994Z
Altcode: 2021arXiv210413564Z; 2020NatAs.tmp..110Z
Solar filaments, also called solar prominences when appearing above the
solar limb, are cold, dense materials suspended in the hot tenuous solar
corona, consisting of numerous long, fibril-like threads. These threads
are the key to disclosing the physics of solar filaments. Similar
structures also exist in galaxy clusters. Besides their mysterious
formation, filament threads are observed to move with alternating
directions, which are called counterstreaming flows. However, the origin
of these flows has not been clarified yet. Here we report that turbulent
heating at the solar surface is the key, which randomly evaporates
materials from the solar surface to the corona, naturally reproducing
the formation and counterstreamings of the sparse threads in the solar
corona. We further suggest that while the cold Hα counterstreamings
are mainly due to longitudinal oscillations of the filament threads,
there are million-kelvin counterstreamings in the corona between
threads, which are alternating unidirectional flows.
Title: Does a Solar Filament Barb Always Correspond to a Prominence
Foot?
Authors: Ouyang, Y.; Chen, P. F.; Fan, S. Q.; Li, B.; Xu, A. A.
Bibcode: 2020ApJ...894...64O
Altcode: 2020arXiv200311976O
Solar filaments are dark structures on the solar disk, with an elongated
spine and several barbs extending out from the spine. When appearing
above the solar limb, a filament is called a prominence, with several
feet extending down to the solar surface. It was generally thought
that filament barbs are simply the prominence feet veering away from
the spine and down to the solar surface. However, it was recently
noticed that there might be another dynamic type of barb, which was
proposed to be due to filament thread longitudinal oscillation. If
this is the case, the dynamic barbs would not extend down to the solar
surface. With the quadrature observations of a filament barb on 2011
June 5 from the Solar Dynamics Observatory and the Solar Terrestrial
Relations Observatory satellites, we confirm that the filament barb
is due to filament thread longitudinal oscillations. Viewed from the
side, the filament barb looks like an appendix along the spine of the
prominence and does not extend down to the solar surface as a foot.
Title: Do the solar flares originating from an individual active
region follow a random process or a memory-dependent correlation?
Authors: Lei, W. H.; Li, C.; Chen, F.; Zhong, S. J.; Xu, Z. G.; Chen,
P. F.
Bibcode: 2020MNRAS.494..975L
Altcode:
We investigate the waiting time statistics of solar flares both in a
flare-productive active region (AR 12673) of the solar cycle 24 and
in a three-dimensional magnetohydrodynamic (MHD) simulated AR. The
statistical models of a discrete random process and a continuous
memory-dependent process are applied to interpret the waiting time
distributions (WTDs) of solar flares. Our results indicate that the
occurrence of a solar flare in an individual AR maintains a certain
amount of memory, and probably arises from MHD turbulence rather than
from intermittent avalanches in a self-organized criticality system. It
differs from the occurrence of 'super flares' when treating the star/Sun
as a single non-linear system.
Title: A New Global Tropospheric Delay Model Considering the
Spatiotemporal Variation Characteristics of ZTD With Altitude
Coefficient
Authors: Chen, Peng; Ma, Yongchao; Liu, Hang; Zheng, Naiquan
Bibcode: 2020E&SS....700888C
Altcode:
Tropospheric delay error is independent of the signal's frequency
and has strong spatiotemporal variation. It is one of the most severe
error sources of satellite navigation and spatial measurement. In view
of the limitation of global zenith tropospheric delay (GZTD) model
considering the altitude coefficient β as a constant and ignoring
its spatiotemporal variation, this paper analyzes the spatiotemporal
distribution of zenith tropospheric delay (ZTD) with altitude variation
coefficient β based on the meteorological reanalysis data provided
by the European Centre for Medium-Range Weather Forecasting from 2011
to 2015. The global altitude coefficient β model is established by
using the trigonometric function and seventh-order spherical harmonics
function model, and then the global tropospheric delay model R_GZTD
(reconstruction GZTD) is reconstructed by using Gbeta (Global beta
β) model. The R_GZTD model gives high-accuracy global distribution
of tropospheric delays without meteorological parameters. The results
show that the internal accuracy of the R_GZTD model is 3.22 cm, which
has a good fitting effect. This paper uses the tropospheric delay
products in 2016-2017 provided by the International GNSS Service, the
tropospheric delay calculated by the European Centre for Medium-Range
Weather Forecasting reanalysis data, and the radiosonde ZTD data in
2016-2017 as external compliance check data. The results show that the
accuracy of the R_GZTD model is better than that of the GZTD model,
UNB3m model, and the global pressure and temperature 2 wet model in the
global and regional scope. Especially in areas with a higher altitude,
the correction effect of the R_GZTD model is more significant. The
root-mean-square error is 8.5% smaller than that of the GZTD model in
the range of 0-500 m, 14.6% smaller in the range of 500-1,000 m, 12.5%
smaller in the range of 1,000-2,000 m, and 16.8% smaller in the range
above 2,000 m. The accuracy with the increasement of height is due
to the fact that the R_GZTD model takes account of the spatiotemporal
variation of β.
Title: Future Physics Programme of BESIII
Authors: Ablikim, M.; Achasov, M. N.; Adlarson, P.; Ahmed, S.;
Albrecht, M.; Alekseev, M.; Amoroso, A.; An, F. F.; An, Q.; Bai, Y.;
Bakina, O.; Baldini Ferroli, R.; Ban, Y.; Begzsuren, K.; Bennett,
J. V.; Berger, N.; Bertani, M.; Bettoni, D.; Bianchi, F.; Biernat,
J.; Bloms, J.; Boyko, I.; Briere, R. A.; Calibbi, L.; Cai, H.; Cai,
X.; Calcaterra, A.; Cao, G. F.; Cao, N.; Cetin, S. A.; Chai, J.;
Chang, J. F.; Chang, W. L.; Charles, J.; Chelkov, G.; Chen; Chen,
G.; Chen, H. S.; Chen, J. C.; Chen, M. L.; Chen, S. J.; Chen, Y. B.;
Cheng, H. Y.; Cheng, W.; Cibinetto, G.; Cossio, F.; Cui, X. F.;
Dai, H. L.; Dai, J. P.; Dai, X. C.; Dbeyssi, A.; Dedovich, D.; Deng,
Z. Y.; Denig, A.; Denysenko, I.; Destefanis, M.; Descotes-Genon, S.;
De Mori, F.; Ding, Y.; Dong, C.; Dong, J.; Dong, L. Y.; Dong, M. Y.;
Dou, Z. L.; Du, S. X.; Eidelman, S. I.; Fan, J. Z.; Fang, J.; Fang,
S. S.; Fang, Y.; Farinelli, R.; Fava, L.; Feldbauer, F.; Felici, G.;
Feng, C. Q.; Fritsch, M.; Fu, C. D.; Fu, Y.; Gao, Q.; Gao, X. L.;
Gao, Y.; Gao, Y.; Gao, Y. G.; Gao, Z.; Garillon, B.; Garzia, I.;
Gersabeck, E. M.; Gilman, A.; Goetzen, K.; Gong, L.; Gong, W. X.;
Gradl, W.; Greco, M.; Gu, L. M.; Gu, M. H.; Gu, Y. T.; Guo, A. Q.;
Guo, F. K.; Guo, L. B.; Guo, R. P.; Guo, Y. P.; Guskov, A.; Han, S.;
Hao, X. Q.; Harris, F. A.; He, K. L.; Heinsius, F. H.; Held, T.; Heng,
Y. K.; Hou, Y. R.; Hou, Z. L.; Hu, H. M.; Hu, J. F.; Hu, T.; Hu, Y.;
Huang, G. S.; Huang, J. S.; Huang, X. T.; Huang, X. Z.; Huang, Z. L.;
Huesken, N.; Hussain, T.; Ikegami Andersson, W.; Imoehl, W.; Irshad,
M.; Ji, Q.; Ji, Q. P.; Ji, X. B.; Ji, X. L.; Jiang, H. L.; Jiang,
X. S.; Jiang, X. Y.; Jiao, J. B.; Jiao, Z.; Jin, D. P.; Jin, S.; Jin,
Y.; Johansson, T.; Kalantar-Nayestanaki, N.; Kang, X. S.; Kappert,
R.; Kavatsyuk, M.; Ke, B. C.; Keshk, I. K.; Khan, T.; Khoukaz, A.;
Kiese, P.; Kiuchi, R.; Kliemt, R.; Koch, L.; Kolcu, O. B.; Kopf, B.;
Kuemmel, M.; Kuessner, M.; Kupsc, A.; Kurth, M.; Kurth, M. G.; Kühn,
W.; Lange, J. S.; Larin, P.; Lavezzi, L.; Leithoff, H.; Lenz, T.; Li,
C.; Li, Cheng; Li, D. M.; Li, F.; Li, F. Y.; Li, G.; Li, H. B.; Li,
H. J.; Li, J. C.; Li, J. W.; Li, Ke; Li, L. K.; Li, Lei; Li, P. L.;
Li, P. R.; Li, Q. Y.; Li, W. D.; Li, W. G.; Li, X. H.; Li, X. L.;
Li, X. N.; Li, X. Q.; Li, Z. B.; Liang, H.; Liang, H.; Liang, Y. F.;
Liang, Y. T.; Liao, G. R.; Liao, L. Z.; Libby, J.; Lin, C. X.; Lin,
D. X.; Lin, Y. J.; Liu, B.; Liu, B. J.; Liu, C. X.; Liu, D.; Liu,
D. Y.; Liu, F. H.; Liu, Fang; Liu, Feng; Liu, H. B.; Liu, H. M.;
Liu, Huanhuan; Liu, Huihui; Liu, J. B.; Liu, J. Y.; Liu, K. Y.; Liu,
Ke; Liu, Q.; Liu, S. B.; Liu, T.; Liu, X.; Liu, X. Y.; Liu, Y. B.;
Liu, Z. A.; Liu, Zhiqing; Long, Y. F.; Lou, X. C.; Lu, H. J.; Lu,
J. D.; Lu, J. G.; Lu, Y.; Lu, Y. P.; Luo, C. L.; Luo, M. X.; Luo,
P. W.; Luo, T.; Luo, X. L.; Lusso, S.; Lyu, X. R.; Ma, F. C.; Ma,
H. L.; Ma, L. L.; Ma, M. M.; Ma, Q. M.; Ma, X. N.; Ma, X. X.; Ma,
X. Y.; Ma, Y. M.; Maas, F. E.; Maggiora, M.; Maldaner, S.; Malde,
S.; Malik, Q. A.; Mangoni, A.; Mao, Y. J.; Mao, Z. P.; Marcello,
S.; Meng, Z. X.; Messchendorp, J. G.; Mezzadri, G.; Min, J.; Min,
T. J.; Mitchell, R. E.; Mo, X. H.; Mo, Y. J.; Morales Morales, C.;
Muchnoi, N. Yu.; Muramatsu, H.; Mustafa, A.; Nakhoul, S.; Nefedov,
Y.; Nerling, F.; Nikolaev, I. B.; Ning, Z.; Nisar, S.; Niu, S. L.;
Olsen, S. L.; Ouyang, Q.; Pacetti, S.; Pan, Y.; Papenbrock, M.;
Patteri, P.; Pelizaeus, M.; Peng, H. P.; Peters, K.; Petrov, A. A.;
Pettersson, J.; Ping, J. L.; Ping, R. G.; Pitka, A.; Poling, R.;
Prasad, V.; Qi, M.; Qi, T. Y.; Qian, S.; Qiao, C. F.; Qin, N.; Qin,
X. P.; Qin, X. S.; Qin, Z. H.; Qiu, J. F.; Qu, S. Q.; Rashid, K. H.;
Redmer, C. F.; Richter, M.; Ripka, M.; Rivetti, A.; Rodin, V.; Rolo,
M.; Rong, G.; Rosner, J. L.; Rosner, Ch.; Rump, M.; Sarantsev, A.;
Savrié, M.; Schoenning, K.; Shan, W.; Shan, X. Y.; Shao, M.; Shen,
C. P.; Shen, P. X.; Shen, X. Y.; Sheng, H. Y.; Shi, X.; Shi, X. D.;
Song, J. J.; Song, Q. Q.; Song, X. Y.; Sosio, S.; Sowa, C.; Spataro,
S.; Sui, F. F.; Sun, G. X.; Sun, J. F.; Sun, L.; Sun, S. S.; Sun,
X. H.; Sun, Y. J.; Sun, Y. K.; Sun, Y. Z.; Sun, Z. J.; Sun, Z. T.;
Tan, Y. T.; Tang, C. J.; Tang, G. Y.; Tang, X.; Thoren, V.; Tsednee,
B.; Uman, I.; Wang, B.; Wang, B. L.; Wang, C. W.; Wang, D. Y.; Wang,
H. H.; Wang, K.; Wang, L. L.; Wang, L. S.; Wang, M.; Wang, M. Z.;
Meng, Wang; Wang, P. L.; Wang, R. M.; Wang, W. P.; Wang, X.; Wang,
X. F.; Wang, X. L.; Wang, Y.; Wang, Y. F.; Wang, Z.; Wang, Z. G.;
Wang, Z. Y.; Wang, Zongyuan; Weber, T.; Wei, D. H.; Weidenkaff, P.;
Wen, H. W.; Wen, S. P.; Wiedner, U.; Wilkinson, G.; Wolke, M.; Wu,
L. H.; Wu, L. J.; Wu, Z.; Xia, L.; Xia, Y.; Xiao, S. Y.; Xiao, Y. J.;
Xiao, Z. J.; Xie, Y. G.; Xie, Y. H.; Xing, T. Y.; Xiong, X. A.; Xiu,
Q. L.; Xu, G. F.; Xu, L.; Xu, Q. J.; Xu, W.; Xu, X. P.; Yan, F.; Yan,
L.; Yan, W. B.; Yan, W. C.; Yan, Y. H.; Yang, H. J.; Yang, H. X.; Yang,
L.; Yang, R. X.; Yang, S. L.; Yang, Y. H.; Yang, Y. X.; Yang, Yifan;
Yang, Z. Q.; Ye, M.; Ye, M. H.; Yin, J. H.; You, Z. Y.; Yu, B. X.;
Yu, C. X.; Yu, J. S.; Yuan, C. Z.; Yuan, X. Q.; Yuan, Y.; Yuncu, A.;
Zafar, A. A.; Zeng, Y.; Zhang, B. X.; Zhang, B. Y.; Zhang, C. C.;
Zhang, D. H.; Zhang, H. H.; Zhang, H. Y.; Zhang, J.; Zhang, J. L.;
Zhang, J. Q.; Zhang, J. W.; Zhang, J. Y.; Zhang, J. Z.; Zhang, K.;
Zhang, L.; Zhang, S. F.; Zhang, T. J.; Zhang, X. Y.; Zhang, Y.; Zhang,
Y. H.; Zhang, Y. T.; Zhang, Yang; Zhang, Yao; Zhang, Yi; Zhang, Yu;
Zhang, Z. H.; Zhang, Z. P.; Zhang, Z. Q.; Zhang, Z. Y.; Zhao, G.;
Zhao, J. W.; Zhao, J. Y.; Zhao, J. Z.; Zhao, Lei; Zhao, Ling; Zhao,
M. G.; Zhao, Q.; Zhao, S. J.; Zhao, T. C.; Zhao, Y. B.; Zhao, Z. G.;
Zhemchugov, A.; Zheng, B.; Zheng, J. P.; Zheng, Y.; Zheng, Y. H.;
Zhong, B.; Zhou, L.; Zhou, L. P.; Zhou, Q.; Zhou, X.; Zhou, X. K.;
Zhou, X. R.; Zhou, Xingyu; Zhou, Xiaoyu; Zhou, Xu; Zhu, A. N.; Zhu,
J.; Zhu, J.; Zhu, K.; Zhu, K. J.; Zhu, S. H.; Zhu, W. J.; Zhu, X. L.;
Zhu, Y. C.; Zhu, Y. S.; Zhu, Z. A.; Zhuang, J.; Zou, B. S.; Zou, J. H.
Bibcode: 2020ChPhC..44d0001A
Altcode: 2019arXiv191205983A
There has recently been a dramatic renewal of interest in hadron
spectroscopy and charm physics. This renaissance has been driven in part
by the discovery of a plethora of charmonium-like XYZ states at BESIII
and B factories, and the observation of an intriguing proton-antiproton
threshold enhancement and the possibly related X(1835) meson state at
BESIII, as well as the threshold measurements of charm mesons and charm
baryons. * Supported in part by National Key Basic Research Program
of China (2015CB856700); National Natural Science Foundation of China
(NSFC) (11335008, 11425524, 11625523, 11635010, 11735014, 11822506,
11935018); the Chinese Academy of Sciences (CAS) Large-Scale Scientific
Facility Program; the CAS Center for Excellence in Particle Physics
(CCEPP); Joint Large-Scale Scientific Facility Funds of the NSFC and CAS
(U1532257, U1532258, U1732263); CAS Key Research Program of Frontier
Science (QYZDJ-SSW-SLH003, QYZDJ-SSW-SLH040); 100 Talents Program
of CAS; CAS PIFI; the Thousand Talents Program of China; INPAC and
Shanghai Key Laboratory for Particle Physics and Cosmology; German
Research Foundation DFG under Contracts Nos. Collaborative Research
Center CRC 1044, FOR 2359; Istituto Nazionale di Fisica Nucleare, Italy;
Koninklijke Nederlandse Akademie van Wetenschappen (KNAW) (530-4CDP03);
Ministry of Development of Turkey (DPT2006K-120470); National Science
and Technology fund; The Knut and Alice Wallenberg Foundation (Sweden)
(2016.0157); The Swedish Research Council; U. S. Department of Energy
(DE-FG02-05ER41374, DESC-0010118, DE-SC-0012069); University of
Groningen (RuG) and the Helmholtzzentrum fuer Schwerionenforschung GmbH
(GSI), Darmstadt; the Russian Ministry of Science and Higher Education
(14.W03.31.0026)
Title: White Paper: ARIANNA-200 high energy neutrino telescope
Authors: Anker, A.; Baldi, P.; Barwick, S. W.; Bergman, D.; Bernhoff,
H.; Besson, D. Z.; Bingefors, N.; Botner, O.; Chen, P.; Chen, Y.;
García-Fernández, D.; Gaswint, G.; Glaser, C.; Hallgren, A.; Hanson,
J. C.; Huang, J. J.; Klein, S. R.; Kleinfelder, S. A.; Kuo, C. -Y.;
Lahmann, R.; Latif, U.; Liu, T.; Lyu, Y.; McAleer, S.; Nam, J.;
Novikov, A.; Nelles, A.; Paul, M. P.; Persichilli, C.; Plaisier, I.;
Shiao, J. Y.; Tatar, J.; van Vliet, A.; Wang, S. -H.; Wang, Y. -H.;
Welling, C.
Bibcode: 2020arXiv200409841A
Altcode:
The proposed ARIANNA-200 neutrino detector, located at sea-level
on the Ross Ice Shelf, Antarctica, consists of 200 autonomous and
independent detector stations separated by 1 kilometer in a uniform
triangular mesh, and serves as a pathfinder mission for the future
IceCube-Gen2 project. The primary science mission of ARIANNA-200 is
to search for sources of neutrinos with energies greater than 10^17
eV, complementing the reach of IceCube. An ARIANNA observation of
a neutrino source would provide strong insight into the enigmatic
sources of cosmic rays. ARIANNA observes the radio emission from
high energy neutrino interactions in the Antarctic ice. Among radio
based concepts under current investigation, ARIANNA-200 would uniquely
survey the vast majority of the southern sky at any instant in time,
and an important region of the northern sky, by virtue of its location
on the surface of the Ross Ice Shelf in Antarctica. The broad sky
coverage is specific to the Moore's Bay site, and makes ARIANNA-200
ideally suited to contribute to the multi-messenger thrust by the US
National Science Foundation, Windows on the Universe - Multi-Messenger
Astrophysics, providing capabilities to observe explosive sources from
unknown directions. The ARIANNA architecture is designed to measure the
angular direction to within 3 degrees for every neutrino candidate,
which too plays an important role in the pursuit of multi-messenger
observations of astrophysical sources.
Title: Reevaluating Mare Moscoviense And Its Vicinity Using Chang'e-2
Microwave Sounder Data
Authors: Meng; Chen; Wang; Wang; Cai; Zhang; Zheng; Hu
Bibcode: 2020RemS...12..535M
Altcode:
No abstract at ADS
Title: VizieR Online Data Catalog: K2 observations of type Ia
supernova SN 2018oh (Dimitriadis+, 2019)
Authors: Dimitriadis, G.; Foley, R. J.; Rest, A.; Kasen, D.; Piro,
A. L.; Polin, A.; Jones, D. O.; Villar, A.; Narayan, G.; Coulter,
D. A.; Kilpatrick, C. D.; Pan, Y. -C.; Rojas-Bravo, C.; Fox, O. D.;
Jha, S. W.; Nugent, P. E.; Riess, A. G.; Scolnic, D.; Drout, M. R.;
Barentsen, G.; Dotson, J.; Gully-Santiago, M.; Hedges, C.; Cody,
A. M.; Barclay, T.; Howell, S.; Garnavich, P.; Tucker, B. E.; Shaya,
E.; Mushotzky, R.; Olling, R. P.; Margheim, S.; Zenteno, A.; Coughlin,
J.; van Cleve, J. E.; Vinicius de, Miranda Cardoso J.; Larson, K. A.;
McCalmont-Everton, K. M.; Peterson, C. A.; Ross, S. E.; Reedy, L. H.;
Osborne, D.; McGinn, C.; Kohnert, L.; Migliorini, L.; Wheaton, A.;
Spencer, B.; Labonde, C.; Castillo, G.; Beerman, G.; Steward, K.;
Hanley, M.; Larsen, R.; Gangopadhyay, R.; Kloetzel, R.; Weschler,
T.; Nystrom, V.; Moffatt, J.; Redick, M.; Griest, K.; Packard, M.;
Muszynski, M.; Kampmeier, J.; Bjella, R.; Flynn, S.; Elsaesser, B.;
Chambers, K. C.; Flewelling, H. A.; Huber, M. E.; Magnier, E. A.;
Waters, C. Z.; Schultz, A. S. B.; Bulger, J.; Lowe, T. B.; Willman,
M.; Smartt, S. J.; Smith, K. W.; Points, S.; Strampelli, G. M.;
Brimacombe, J.; Chen, P.; Munoz, J. A.; Mutel, R. L.; Shields, J.;
Vallely, P. J.; Villanueva, S.; Li, W.; Wang, X.; Zhang, J.; Lin, H.;
Mo, J.; Zhao, X.; Sai, H.; Zhang, X.; Zhang, K.; Zhang, T.; Wang,
L.; Zhang, J.; Baron, E.; Derkacy, J. M.; Li, L.; Chen, Z.; Xiang,
D.; Rui, L.; Wang, L.; Huang, F.; Li, X.; Hosseinzadeh, G.; Howell,
D. A.; Arcavi, I.; Hiramatsu, D.; Burke, J.; Valenti, S.; Tonry,
J. L.; Denneau, L.; Heinze, A. N.; Weiland, H.; Stalder, B.; Vinko,
J.; Sarneczky, K.; Pal, A.; Bodi, A.; Bognar, Z.; Csak, B.; Cseh,
B.; Csornyei, G.; Hanyecz, O.; Ignacz, B.; Kalup, C.; Konyves-Toth,
R.; Kriskovics, L.; Ordasi, A.; Rajmon, I.; Sodor, A.; Szabo, R.;
Szakats, R.; Zsidi, G.; Williams, S. C.; Nordin, J.; Cartier, R.;
Frohmaier, C.; Galbany, L.; Gutierrez, C. P.; Hook, I.; Inserra, C.;
Smith, M.; Sand, D. J.; Andrews, J. E.; Smith, N.; Bilinski, C.
Bibcode: 2020yCat..18709001D
Altcode:
SN 2018oh was discovered by the All Sky Automated Survey for SuperNovae
(ASAS-SN) in images obtained on 2018 February 4.41 UT. The
supernova is located 7.8" north and 2.0" east of the center of UGC
4780, an Sdm star-forming galaxy, with a redshift of z=0.010981
and a distance of 49.4Mpc. UGC 4780 was included as a Campaign 16
target through "The K2 ExtraGalactic Survey (KEGS) for Transients"
(PI: A. Rest) and the "Multi-Observatory Monitoring of K2 Supernovae"
(PI: R. J. Foley) programs as part of the K2 SCE (internal Kepler ID
228682548). The UGC 4780 data were retrieved from MAST. We also
observed the K2 field with both the Panoramic Survey Telescope and
Rapid Response System 1 (Pan-STARRS1) telescope and the Cerro Tololo
Inter-American Observatory (CTIO) 4m Mayall telescope with the Dark
Energy Camera (DECam) during Campaign 16. (1 data file).
Title: Accuracy and consistency of different global ionospheric maps
released by IGS ionosphere associate analysis centers
Authors: Chen, Peng; Liu, Hang; Ma, Yongchao; Zheng, Naiquan
Bibcode: 2020AdSpR..65..163C
Altcode:
Due to the differences of ionospheric modeling methods and selected
tracking stations, the accuracy and consistency of Global Ionospheric
Maps (GIMs) released by Ionosphere Associate Analysis Centers (IAACs)
are different. In this study, we evaluate and analyze in detail the
accuracy and consistency of GIMs final products provided by six IAACs
from three different aspects. Firstly, the comparison of these GIMs
shows that the mean bias (MEAN) is related to the modeling methods of
various IAACs. The variation trend of the standard deviation (STD)
is consistent with the solar activities, and accompanied by certain
seasonal and annual periodic variations. The MEAN between IGS and
each center is about -1.3 to 1.0 TECU, and the STD is about 1.4-2.5
TECU. Secondly, the validation with GPS TEC shows that the STD of CODE
is the smallest at various latitudes, and the STD is about 0.7-4.5
TECU. Thirdly, The validation with the Jason2 VTEC shows that the STD
between Jason2 and IAACs is about 4.4-5.2 TECU. In addition, the STD
between Jason2 and six GIMs in the areas with more tracking stations
is better than that of the regions with fewer tracking stations in
different latitude regions. Regardless of whether the tracking stations
are more or less, the MEAN and STD in high solar activity are larger
than in low solar activity.
Title: Spectroscopic classification of ASASSN-19adm/2019xfi with SALT
Authors: Chen, P.; Dong, S.; Gromadzki, M.; Buckley, D. A. H.
Bibcode: 2020TNSAN..12....1C
Altcode:
We report SALT spectroscopic classification for ASASSN-19adm/2019xfi
as a SN Ia at about three weeks after the peak.
Title: Modelling Global Ionosphere Based on Multi-frequency,
Multi-constellation GNSS Observations and IRI Model
Authors: An; Meng; Chen; Jiang; Xi; Chen
Bibcode: 2020RemS...12..439A
Altcode:
No abstract at ADS
Title: A global empirical orthogonal function model of plasmaspheric
electron content
Authors: Chen, Peng; Liu, Lixia; Yao, Yibin; Yao, Wanqiang
Bibcode: 2020AdSpR..65..138C
Altcode:
Based on the method for establishing a global plasmaspheric model using
observations from COSMIC and MetOp-A orbit determination GNSS receivers,
Chen et al. (2017) obtained a global plasmaspheric total electron
content product with a spatial resolution of 2.5° × 5° and a time
resolution of 4 h. In this paper, we use those global plasmaspheric
electron content product in 2008, 2010, 2011, 2012, 2014 for 1446
days to establish a global plasmaspheric empirical model based on
empirical orthogonal function (EOF). The model can well characterize
the spatiotemporal variation of plasmaspheric electron content (PEC)
and the influence of solar radiation on it. Only the first four orders
of EOF sequences can characterize the 98.43% features of the original
PEC dataset. The principal component coefficient Pk is decomposed twice
during modeling, and the combination of trigonometric function and
linear function is used to model Pk to characterize the solar cycle,
annual cycle, semi-annual cycle and quarter-cycle variation. We compare
the PEC model values with the actual observation data, the results
show that the empirical PEC model values are highly correlated with
the actual observations. The correlation between the two is above 0.96,
and the RMS maximum of the difference between the PEC model values and
the observed values are 0.70 TECU, and the average of the difference
between the PEC model values and the observed values are -0.18 TECU,
respectively. In addition, we validate the reliability of the global
plasmaspheric model established by two empirical orthogonal function
decomposition method using actual observation data, according to the
global distribution of the differences between the PEC model values
and the observed values in low solar activity and high solar activity,
it can be seen that under low solar activity and high solar activity
conditions, the model has good adaptability.
Title: Transient Classification Report for 2020-01-13
Authors: Chen, P.; Dong, S.; Gromadzki, M.; Buckley, D. A. H.
Bibcode: 2020TNSCR.124....1C
Altcode:
No abstract at ADS
Title: Transient Classification Report for 2020-01-18
Authors: Chen, P.; Dong, S.; Al, M. D. S. E.
Bibcode: 2020TNSCR1483....1C
Altcode:
No abstract at ADS
Title: VizieR Online Data Catalog: K2 light curve alternative analysis
of ASASSN-18bt (Shappee+, 2019)
Authors: Shappee, B. J.; Holoien, T. W. -S.; Drout, M. R.; Auchettl,
K.; Stritzinger, M. D.; Kochanek, C. S.; Stanek, K. Z.; Shaya,
E.; Narayan, G.; ASAS-SN Collaboration); Brown, J. S.; Bose, S.;
Bersier, D.; Brimacombe, J.; Chen, P.; Dong, S.; Holmbo, S.; Katz,
B.; Munoz, J. A.; Mutel, R. L.; Post, R. S.; Prieto, J. L.; Shields,
J.; Tallon, D.; Thompson, T. A.; Vallely, P. J.; Villanueva, S.;
Atlas Collaboration; Denneau, L.; Flewelling, H.; Heinze, A. N.;
Smith, K. W.; Stalder, B.; Tonry, J. L.; Weiland, H.; Barclay, T.;
Barentsen, G.; Cody, A. M.; Dotson, J.; Foerster, F.; Garnavich, P.;
Gully-Santiago, M.; Hedges, C.; Howell, S.; Kasen, D.; Margheim, S.;
Mushotzky, R.; Rest, A.; Tucker, B. E.; Villar, A.; Zenteno A.; Kepler
Spacecraft Team; Beerman, G.; Bjella, R.; Castillo, G.; Coughlin, J.;
Elsaesser, B.; Flynn, S.; Gangopadhyay, R.; Griest, K.; Hanley, M.;
Kampmeier, J.; Kloetzel, R.; Kohnert, L.; Labonde, C.; Larsen, R.;
Larson, K. A.; McCalmont-Everton, K. M.; McGinn, C.; Migliorini, L.;
Moffatt, J.; Muszynski, M.; Nystrom, V.; Osborne, D.; Packard, M.;
Peterson, C. A.; Redick, M.; Reed Y, L. H.; Ross, S. E.; Spencer,
B.; Steward, K.; van Cleve, J. E.; Vinicius de, Miranda Cardoso J.;
Weschler, T.; Wheaton, A.; Pan-Starrs Collaboration; Bulger, J.;
Chambers, K. C.; Flewelling, H. A.; Huber, M. E.; Lowe, T. B.; Magnier,
E. A.; Schultz, A. S. B.; Waters, C. Z.; Willman, M.; Baron, E.; Chen,
Z.; Derkacy, J. M.; Huang, F.; Li, L.; Li, W.; Li, X.; Mo, J.; Rui, L.;
Sai, H.; Wang, L.; Wang, L.; Wang, X.; Xiang, D.; Zhang, J.; Zhang, J.;
Zhang, K.; Zhang, T.; Zhang, X.; Zhao, X.; Brown, P. J.; Hermes, J. J.;
Nordin, J.; Points, S.; Sodor, A.; Strampelli, G. M.; Zenteno, A.
Bibcode: 2020yCat..18700013S
Altcode:
ASASSN-18bt was discovered at RAJ2000=09:06:39.54, DEJ2000=+19:20:17.77
in V-band images obtained by the ASAS-SN unit "Brutus", located
on Haleakala in Hawaii on 2018 February 4.410 UT. The All-Sky
Automated Survey for SuperNovae (ASAS-SN; Shappee+ 2014, J/ApJ/788/48)
is an ongoing project which uses units of four 14cm lenses on a common
mount hosted by the Las Cumbres Observatory global telescope network
at multiple sites around the globe. After expanding our network in
2017, we currently have five units located in Hawaii, Chile, Texas,
and South Africa, allowing us to observe the entire sky every ~20hr,
weather permitting, to a depth of g~18.5mag. As part of the
community effort to support K2 Campaign 16, ASAS-SN was monitoring the
K2 field with an increased cadence. The effort to monitor the entire K2
field of view multiple times per day was continued through Campaign 17
and will be extended to monitor the TESS fields four to six times per
day. We performed forced photometry on the subtracted "Asteroid
Terrestrial-impact Last Alert System" (ATLAS) images of ASASSN-18bt
as described in Tonry+ (2018PASP..130f4505T). ATLAS scans the entire
sky accessible from Hawaii every few days using fully robotic 0.5m
f/2 Wright Schmidt telescopes located on the summit of Haleakala and
at Mauna Loa Observatory. The ATLAS telescopes use two broad filters:
the "cyan" filter (c) covering 420-650nm and the "orange" filter (o)
covering 560-820nm. (1 data file).
Title: Synthetic Spectra of Potential Exo-Earths: Quantifying Biotic
Signatures with AROC
Authors: Dick, S.; Li, M.; Adams, D.; Kataria, T.; Chen, P.; Perl,
S. M.; Barge, L. M.; Yung, Y. L.
Bibcode: 2019AGUFM.P51H3452D
Altcode:
As exoplanet transmission spectra become possible for smaller planets,
it becomes pertinent to question what we expect to observe from an
exo-Earth. Previously, atmospheric and aqueous chemistry models have
been used independently to investigate atmospheric and surface processes
taking place on terrestrial exoplanets. However, these two models cannot
be treated discretely. We present the AROC (Atmosphere-Rock-Ocean
Chemistry) model, which couples KINETICS (the Caltech/JPL 1-D
photochemical and transport model, Allen et al. 1981) with PHREEQC
(the USGS ion-association aqueous chemistry model, Parkhurst and
Appelo 2013) to incorporate atmosphere-ocean-rock interactions in
near-surface exoplanet chemistry for terrestrial exoplanets. The
KINETICS model currently set up for early Earth includes 50 (9 fixed,
41 varied) chemical species linked by 297 reactions, including nitrogen
and sulfur chemistry and volcanic outgassing at the lower boundary. At
each time step, PHREEQC calculates a gaseous flux input for KINETICS in
order for AROC to achieve surface-atmospheric equilibrium. The output
from this comprehensive model is then fed to petitRADTRANS (Mollière
et al. 2019) to generate synthetic transmission spectra. We consider
the following potential Earth-like exoplanet compositions: a pre-GOE
(Great Oxidation Event), abiotic Earth; an abiotic Earth during the GOE
with increasing oxygen fluxes; and a post-GOE, biotic Earth modeled
with microbial outgassing. Our AROC results and derived spectra will
therefore aid in quantifying the effect of biological processes on
transmission spectroscopy and can be used to make predictions for future
telescopes that would observe potentially habitable planets, including
the James Webb Space Telescope (JWST), Origins Space Telescope (OST),
LUVOIR, and HabEx.
Title: Constraints on the Diffuse Flux of Ultra-High Energy Neutrinos
from Four Years of Askaryan Radio Array Data in Two Stations
Authors: ARA Collaboration; Allison, P.; Archambault, S.; Beatty,
J. J.; Beheler-Amass, M.; Besson, D. Z.; Beydler, M.; Chen,
C. C.; Chen, C. H.; Chen, P.; Clark, B. A.; Clay, W.; Connolly, A.;
Cremonesi, L.; Davies, J.; de Kockere, S.; de Vries, K. D.; Deaconu,
C.; Duvernois, M.; Friedman, E.; Gaior, R.; Hanson, J.; Hanson, K.;
Hoffman, K. D.; Hokanson-Fasig, B.; Hong, E.; Hsu, S. Y.; Hu, L.;
Huang, J. J.; Huang, M. -H.; Hughes, K.; Ishihara, A.; Karle, A.;
Kelley, J. L.; Khandelwal, R.; Kim, K. -C.; Kim, M. -C.; Kravchenko,
I.; Kurusu, K.; Landsman, H.; Latif, U. A.; Laundrie, A.; Li,
C. -J.; Liu, T. -C.; Lu, M. -Y.; Madison, B.; Mase, K.; Meures, T.;
Nam, J.; Nichol, R. J.; Nir, G.; Novikov, A.; Nozdrina, A.; Oberla,
E.; O'Murchadha, A.; Osborn, J.; Pan, Y.; Pfendner, C.; Roth, J.;
Sandstrom, P.; Seckel, D.; Shiao, Y. -S.; Shultz, A.; Smith, D.;
Torres, J.; Touart, J.; van Eijndhoven, N.; Varner, G. S.; Vieregg,
A. G.; Wang, M. -Z.; Wang, S. -H.; Wissel, S. A.; Yoshida, S.;
Young, R.
Bibcode: 2019arXiv191200987A
Altcode:
The Askaryan Radio Array (ARA) is an ultra-high energy (UHE,
$>10^{17}$ eV) neutrino detector designed to observe neutrinos by
searching for the radio waves emitted by the relativistic products
of neutrino-nucleon interactions in Antarctic ice. In this paper,
we present constraints on the diffuse flux of ultra-high energy
neutrinos between $10^{16}-10^{21}$ eV resulting from a search for
neutrinos in two complementary analyses, both analyzing four years
of data (2013-2016) from the two deep stations (A2, A3) operating
at that time. We place a 90 % CL upper limit on the diffuse all
flavor neutrino flux at $10^{18}$ eV of $EF(E)=5.6\times10^{-16}$
$\textrm{cm}^{-2}$$\textrm{s}^{-1}$$\textrm{sr}^{-1}$. This analysis
includes four times the exposure of the previous ARA result, and
represents approximately 1/5 the exposure expected from operating ARA
until the end of 2022.
Title: Localizing Putative Methane Sources on Mars from
Back-Trajectory Modeling Techniques
Authors: Luo, Y.; Mischna, M.; Yung, Y. L.; Kleinboehl, A.; Chen, P.
Bibcode: 2019AGUFM.P41B3419L
Altcode:
A variety of measurements of methane in the Martian atmosphere
have been made over the past 15 years, showing wildly varying
indications of methane abundance, location and lifetime in the Martian
atmosphere. Attempts have been made to use numerical tools such as
general circulation models (GCMs) to identify source locations and
timing of methane releases, but these remain inconclusive under the
current approach of forward-trajectory plume modeling. Here we present
results using a novel, complementary method of localizing methane
surface sources by modeling passive tracer trajectories backwards
in time from the locations where observations of atmospheric methane
have been made. Such back-trajectory modeling employs both GCM modeled
winds and a Lagrangian particle dispersion model to isolate potential
upwind sources of the observed signals. This approach avoids many
of the pitfalls inherent in forward-trajectory modeling approaches
such as numerical diffusion and subgrid-scale motion which cannot be
captured in the Eulerian framework of a GCM. We have chosen to
focus on localization of the detection of methane by the Planetary
Fourier Spectrometer near Gale crater around Ls=336°
in MY 31. This observation is consistent with a near-coincident
enhanced methane 'spike' observed by the Mars Science Laboratory
TLS instrument. We have chosen to use the Stochastic Time-Inverted
Lagrangian Transport (STILT) particle dispersion model in conjunction
with the Mars Weather Research and Forecasting (MarsWRF) GCM for our
back-trajectory modeling. To date, we have combined MarsWRF output with
a more basic trajectory model, which advects particles based on bulk
winds, and have found areas of enhanced tracer density to the north
of Gale crater at prior times. Incorporation of turbulent processes
in the planetary boundary layer will subject these preliminary results
into test. And g eological context will also be used to constrain the
likelihood of these methane source locations.
Title: Neutrino astronomy with the next generation IceCube Neutrino
Observatory
Authors: Aartsen, M. G.; Ackermann, M.; Adams, J.; Aguilar, J. A.;
Ahlers, M.; Ahrens, M.; Alispach, C.; Andeen, K.; Anderson, T.;
Ansseau, I.; Anton, G.; Argüelles, C.; Arlen, T. C.; Auffenberg, J.;
Axani, S.; Backes, P.; Bagherpour, H.; Bai, X.; Balagopal V., A.;
Barbano, A.; Bartos, I.; Bastian, B.; Baum, V.; Baur, S.; Bay, R.;
Beatty, J. J.; Becker, K. -H.; Becker Tjus, J.; BenZvi, S.; Berley,
D.; Bernardini, E.; Besson, D. Z.; Binder, G.; Bindig, D.; Blaufuss,
E.; Blot, S.; Bohm, C.; Bohmer, M.; Börner, M.; Böser, S.; Botner,
O.; Böttcher, J.; Bourbeau, E.; Bourbeau, J.; Bradascio, F.; Braun,
J.; Bron, S.; Brostean-Kaiser, J.; Burgman, A.; Buscher, J.; Busse,
R. S.; Bustamante, M.; Carver, T.; Chen, C.; Chen, P.; Cheung, E.;
Chirkin, D.; Clark, B.; Clark, K.; Classen, L.; Coleman, A.; Collin,
G. H.; Connolly, A.; Conrad, J. M.; Coppin, P.; Correa, P.; Cowen,
D. F.; Cross, R.; Dave, P.; Deaconu, C.; de André, J. P. A. M.; De
Clercq, C.; DeKockere, S.; DeLaunay, J. J.; Dembinski, H.; Deoskar,
K.; De Ridder, S.; Desiati, P.; de Vries, K. D.; de Wasseige, G.; de
With, M.; DeYoung, T.; Diaz, A.; Díaz-Vélez, J. C.; Dujmovic, H.;
Dunkman, M.; DuVernois, M. A.; Dvorak, E.; Eberhardt, B.; Ehrhardt,
T.; Eller, P.; Engel, R.; Evans, J. J.; Evenson, P. A.; Fahey, S.;
Farrag, K.; Fazely, A. R.; Felde, J.; Filimonov, K.; Finley, C.;
Franckowiak, A.; Friedman, E.; Fritz, A.; Gaisser, T. K.; Gallagher,
J.; Ganster, E.; Garcia-Fernandez, D.; Garrappa, S.; Gartner, A.;
Gerhardt, L.; Gernhaeuser, R.; Ghorbani, K.; Glauch, T.; Glüsenkamp,
T.; Goldschmidt, A.; Gonzalez, J. G.; Grant, D.; Griffith, Z.; Günder,
M.; Gündüz, M.; Haack, C.; Hallgren, A.; Halve, L.; Halzen, F.;
Hanson, K.; Haugen, J.; Haungs, A.; Hebecker, D.; Heereman, D.;
Heix, P.; Helbing, K.; Hellauer, R.; Henningsen, F.; Hickford, S.;
Hignight, J.; Hill, G. C.; Hoffman, K. D.; Hoffmann, B.; Hoffmann,
R.; Hoinka, T.; Hokanson-Fasig, B.; Holzapfel, K.; Hoshina, K.;
Huang, F.; Huber, M.; Huber, T.; Huege, T.; Hughes, K.; Hultqvist,
K.; Hünnefeld, M.; Hussain, R.; In, S.; Iovine, N.; Ishihara, A.;
Japaridze, G. S.; Jeong, M.; Jero, K.; Jones, B. J. P.; Jonske, F.;
Joppe, R.; Kalekin, O.; Kang, D.; Kang, W.; Kappes, A.; Kappesser,
D.; Karg, T.; Karl, M.; Karle, A.; Katori, T.; Katz, U.; Kauer, M.;
Keivani, A.; Kelley, J. L.; Kheirandish, A.; Kim, J.; Kintscher, T.;
Kiryluk, J.; Kittler, T.; Klein, S. R.; Koirala, R.; Kolanoski, H.;
Köpke, L.; Kopper, C.; Kopper, S.; Koskinen, D. J.; Kowalski, M.;
Krauss, C. B.; Krings, K.; Krückl, G.; Kulacz, N.; Kurahashi, N.;
Kyriacou, A.; Labare, M.; Lanfranchi, J. L.; Larson, M. J.; Latif,
U.; Lauber, F.; Lazar, J. P.; Leonard, K.; Leszczynska, A.; Leuermann,
M.; Liu, Q. R.; Lohfink, E.; LoSecco, J.; Lozano Mariscal, C. J.; Lu,
L.; Lucarelli, F.; Lünemann, J.; Luszczak, W.; Lyu, Y.; Ma, W. Y.;
Madsen, J.; Maggi, G.; Mahn, K. B. M.; Makino, Y.; Mallik, P.; Mallot,
K.; Mancina, S.; Mandalia, S.; Maris, I. C.; Marka, S.; Marka, Z.;
Maruyama, R.; Mase, K.; Maunu, R.; McNally, F.; Meagher, K.; Medici,
M.; Medina, A.; Meier, M.; Meighen-Berger, S.; Menne, T.; Merino,
G.; Meures, T.; Micallef, J.; Momenté, G.; Montaruli, T.; Moore,
R. W.; Morse, R.; Moulai, M.; Muth, P.; Nagai, R.; Nam, J.; Naumann,
U.; Neer, G.; Nelles, A.; Niederhausen, H.; Nowicki, S. C.; Nygren,
D. R.; Obertacke Pollmann, A.; Oehler, M.; Olivas, A.; O'Murchadha,
A.; O'Sullivan, E.; Palczewski, T.; Pandya, H.; Pankova, D. V.; Papp,
L.; Park, N.; Peiffer, P.; Pérez de los Heros, C.; Petersen, T. C.;
Philippen, S.; Pieloth, D.; Pinat, E.; Pinfold, J. L.; Pizzuto, A.;
Plaisier, I.; Plum, M.; Porcelli, A.; Price, P. B.; Przybylski, G. T.;
Raab, C.; Raissi, A.; Rameez, M.; Rauch, L.; Rawlins, K.; Rea, I. C.;
Reimann, R.; Relethford, B.; Renschler, M.; Renzi, G.; Resconi, E.;
Rhode, W.; Richman, M.; Riegel, M.; Robertson, S.; Rongen, M.; Rott,
C.; Ruhe, T.; Ryckbosch, D.; Rysewyk, D.; Safa, I.; Sanchez Herrera,
S. E.; Sandrock, A.; Sandroos, J.; Sandstrom, P.; Santander, M.;
Sarkar, S.; Sarkar, S.; Satalecka, K.; Schaufel, M.; Schieler, H.;
Schlunder, P.; Schmidt, T.; Schneider, A.; Schneider, J.; Schröder,
F. G.; Schumacher, L.; Sclafani, S.; Seckel, D.; Seunarine, S.;
Shaevitz, M. H.; Shefali, S.; Silva, M.; Smith, D.; Snihur, R.;
Soedingrekso, J.; Soldin, D.; Söldner-Rembold, S.; Song, M.; Southall,
D.; Spiczak, G. M.; Spiering, C.; Stachurska, J.; Stamatikos, M.;
Stanev, T.; Stein, R.; Steinmüller, P.; Stettner, J.; Steuer, A.;
Stezelberger, T.; Stokstad, R. G.; Stößl, A.; Strotjohann, N. L.;
Stürwald, T.; Stuttard, T.; Sullivan, G. W.; Taboada, I.; Taketa, A.;
Tanaka, H. K. M.; Tenholt, F.; Ter-Antonyan, S.; Terliuk, A.; Tilav,
S.; Tomankova, L.; Tönnis, C.; Torres, J.; Toscano, S.; Tosi, D.;
Trettin, A.; Tselengidou, M.; Tung, C. F.; Turcati, A.; Turcotte, R.;
Turley, C. F.; Ty, B.; Unger, E.; Unland Elorrieta, M. A.; Usner, M.;
Vandenbroucke, J.; Van Driessche, W.; van Eijk, D.; van Eijndhoven,
N.; Vanheule, S.; Vieregg, A.; van Santen, J.; Veberic, D.; Vraeghe,
M.; Walck, C.; Wallace, A.; Wallraff, M.; Wandkowsky, N.; Watson,
T. B.; Weaver, C.; Weindl, A.; Weiss, M. J.; Weldert, J.; Welling,
C.; Wendt, C.; Werthebach, J.; Whelan, B. J.; Whitehorn, N.; Wiebe,
K.; Wiebusch, C. H.; Wille, L.; Williams, D. R.; Wills, L.; Wissel,
S.; Wolf, M.; Wood, J.; Wood, T. R.; Woschnagg, K.; Wrede, G.; Wren,
S.; Xu, D. L.; Xu, X. W.; Xu, Y.; Yanez, J. P.; Yodh, G.; Yoshida,
S.; Yuan, T.; Zöcklein, M.
Bibcode: 2019arXiv191102561A
Altcode:
The past decade has welcomed the emergence of cosmic neutrinos as a new
messenger to explore the most extreme environments of the universe. The
discovery measurement of cosmic neutrinos, announced by IceCube in
2013, has opened a new window of observation that has already resulted
in new fundamental information that holds the potential to answer key
questions associated with the high-energy universe, including: what are
the sources in the PeV sky and how do they drive particle acceleration;
where are cosmic rays of extreme energies produced, and on which paths
do they propagate through the universe; and are there signatures of
new physics at TeV-PeV energies and above? The planned advancements
in neutrino telescope arrays in the next decade, in conjunction with
continued progress in broad multimessenger astrophysics, promise to
elevate the cosmic neutrino field from the discovery to the precision
era and to a survey of the sources in the neutrino sky. The planned
detector upgrades to the IceCube Neutrino Observatory, culminating in
IceCube-Gen2 (an envisaged $400M facility with anticipated operation
in the next decade, described in this white paper) are the cornerstone
that will drive the evolution of neutrino astrophysics measurements.
Title: Chinese Hα Solar Explorer (CHASE) - a complementary space
mission to the ASO-S
Authors: Li, Chuan; Fang, Cheng; Li, Zhen; Ding, Ming-De; Chen,
Peng-Fei; Chen, Zhe; Lin, Liang-Kui; Chen, Chang-Zheng; Chen, Chang-Ya;
Tao, Hong-Jiang; You, Wei; Hao, Qi; Dai, Yu; Cheng, Xin; Guo, Yang;
Hong, Jie; An, Min-Jie; Cheng, Wei-Qiang; Chen, Jian-Xin; Wang, Wei;
Zhang, Wei
Bibcode: 2019RAA....19..165L
Altcode:
The Chinese Hα Solar Explorer (CHASE) is designed to test a newly
developed satellite platform and conduct solar observations. The
scientific payload of the satellite is an Hα imaging spectrograph
(HIS), which can, for the first time, acquire full-disk spectroscopic
solar observations in the Hα waveband. This paper briefly introduces
CHASE/HIS including its scientific objectives, technical parameters,
scientific application system, etc. The CHASE mission is scheduled to
launch in 2021. It will complement the observations by on-orbit solar
spacecraft (such as SDO, IRIS, STEREO and PSP), as well as future solar
missions of the Solar Orbiter and Advanced Space-based Solar Observatory
(ASO-S).
Title: Possible Uptake of Mars Atmospheric Gases by an Extant
Biosphere
Authors: Chen, P.; Yung, Y. L.
Bibcode: 2019LPICo2108.5061C
Altcode:
This talk discusses Mars’ atmospheric composition in the context of
gas uptake by a possible biosphere and future measurement strategies.
Title: Study on the plasmaspheric Weddell Sea Anomaly based on COSMIC
onboard GPS measurements
Authors: Chen, Peng; Li, Qinzheng; Yao, Yibin; Yao, WanQiang
Bibcode: 2019JASTP.19204923C
Altcode:
This study investigated the morphology of the Plasmaspheric Weddell Sea
Anomaly (PWSA). Measurements by GPS receivers onboard COSMIC satellites
were used to determine the slant total electron content (STEC) along
signal propagation paths during 2007-2017, which were converted to the
zenith direction using a specific plasmaspheric projection function to
obtain vertical total electron content (VTEC). The characteristics of
seasonal variation of the PWSA between the four seasons were examined
under conditions of high and low solar activity that corresponded
to values of the F10.7 index of >120 and ≤ 120, respectively. To
investigate seasonal variation of plasmaspheric VTEC, maps of geographic
latitude versus geographic longitude were constructed by binning the
data into 5° latitudinal grids and 15° longitudinal grids. The median
value of VTEC in each grid was calculated for each season under low
and high solar activity conditions. The results showed that the WSA
phenomenon could also be observed in the plasmasphere (altitude ≥
800 km) as well as in the ionosphere. The anomaly is most prominent in
winter under conditions of high solar activity, and it also can be found
in spring and autumn, although its amplitude is relatively small. The
equatorward neutral wind is the critical driver for PWSA formation. In
addition, during the polar summer, high geographic latitudes are sunlit
during the entire day, leading to prolonged photoionization. This is
the most essential process for the existence of the nighttime maximum
in the VTEC diurnal variation at the geographic latitudes of the PWSA.
Title: Damping Mechanisms of the Solar Filament Longitudinal
Oscillations in the Weak Magnetic Field
Authors: Zhang, L. Y.; Fang, C.; Chen, P. F.
Bibcode: 2019ApJ...884...74Z
Altcode: 2019arXiv190807148Z
Longitudinal oscillations of the solar filament have been
investigated via numerical simulations continuously, but mainly
in one dimension, where the magnetic field line is treated as a
rigid flux tube. Whereas those one-dimensional (1D) simulations
can roughly reproduce the observed oscillation periods, implying
that gravity is the main restoring force for filament longitudinal
oscillations, the decay time in 1D simulations is generally longer
than in observations. In this paper, we perform a two-dimensional (2D)
nonadiabatic magnetohydrodynamic simulation of filament longitudinal
oscillations, and compare it with the 2D adiabatic case and 1D adiabatic
and nonadiabatic cases. It is found that, whereas both nonadiabatic
processes (radiation and heat conduction) can significantly reduce the
decay time, wave leakage is another important mechanism to dissipate
the kinetic energy of the oscillating filament when the magnetic field
is weak so that gravity is comparable to Lorentz force. In this case,
our simulations indicate that the pendulum model might lead to an error
of ∼100% in determining the curvature radius of the dipped magnetic
field using the longitudinal oscillation period when the gravity to
Lorentz force ratio is close to unity.
Title: The Magnetic Flux Rope Structure of a Triangulated Solar
Filament
Authors: Guo, Yang; Xu, Yu; Ding, M. D.; Chen, P. F.; Xia, Chun;
Keppens, Rony
Bibcode: 2019ApJ...884L...1G
Altcode:
Solar magnetic flux ropes are core structures driving solar
activities. We construct a magnetic flux rope for a filament/prominence
observed at 01:11 UT on 2011 June 21 in AR 11236 with a combination of
state-of-the-art methods, including triangulation from multiperspective
observations, the flux rope embedding method, the regularized
Biot-Savart laws, and the magnetofrictional method. First, the path
of the filament is reconstructed via the triangulation with 304 Å
images observed by the Atmospheric Imaging Assembly on board Solar
Dynamics Observatory (SDO) and by the Extreme Ultraviolet Imager on
board the twin Solar Terrestrial Relations Observatory. Then, a flux
rope is constructed with the regularized Biot-Savart laws using the
information of its axis. Next, it is embedded into a potential magnetic
field computed from the photospheric radial magnetic field observed by
the Helioseismic and Magnetic Imager on board SDO. The combined magnetic
field is finally relaxed by the magnetofrictional method to reach a
nonlinear force-free state. It is found that both models constructed
by the regularized Biot-Savart laws and after the magnetofrictional
relaxation coincide with the 304 Å images. The distribution of magnetic
dips coincides with part of the filament/prominence material, and
the quasi-separatrix layers wrap the magnetic flux ropes, displaying
hyperbolic flux tube structures. These models have the advantages of
constructing magnetic flux ropes in the higher atmosphere and weak
magnetic field regions, which could be used as initial conditions for
magnetohydrodynamic simulations of coronal mass ejections.
Title: Evidence for a Chandrasekhar-mass explosion in the Ca-strong
1991bg-like type Ia supernova 2016hnk
Authors: Galbany, L.; Ashall, C.; Höflich, P.; González-Gaitán, S.;
Taubenberger, S.; Stritzinger, M.; Hsiao, E. Y.; Mazzali, P.; Baron,
E.; Blondin, S.; Bose, S.; Bulla, M.; Burke, J. F.; Burns, C. R.;
Cartier, R.; Chen, P.; Della Valle, M.; Diamond, T. R.; Gutiérrez,
C. P.; Harmanen, J.; Hiramatsu, D.; Holoien, T. W. -S.; Hosseinzadeh,
G.; Howell, D. Andrew; Huang, Y.; Inserra, C.; de Jaeger, T.; Jha,
S. W.; Kangas, T.; Kromer, M.; Lyman, J. D.; Maguire, K.; Marion,
G. Howie; Milisavljevic, D.; Prentice, S. J.; Razza, A.; Reynolds,
T. M.; Sand, D. J.; Shappee, B. J.; Shekhar, R.; Smartt, S. J.;
Stassun, K. G.; Sullivan, M.; Valenti, S.; Villanueva, S.; Wang, X.;
Wheeler, J. Craig; Zhai, Q.; Zhang, J.
Bibcode: 2019A&A...630A..76G
Altcode: 2019arXiv190410034G
Aims: We present a comprehensive dataset of optical and
near-infrared photometry and spectroscopy of type Ia supernova (SN)
2016hnk, combined with integral field spectroscopy (IFS) of its
host galaxy, MCG -01-06-070, and nearby environment. Our goal with
this complete dataset is to understand the nature of this peculiar
object.
Methods: Properties of the SN local environment are
characterized by means of single stellar population synthesis applied to
IFS observations taken two years after the SN exploded. We performed
detailed analyses of SN photometric data by studying its peculiar
light and color curves. SN 2016hnk spectra were compared to other
1991bg-like SNe Ia, 2002es-like SNe Ia, and Ca-rich transients. In
addition, we used abundance stratification modeling to identify the
various spectral features in the early phase spectral sequence and
also compared the dataset to a modified non-LTE model previously
produced for the sublumnious SN 1999by.
Results: SN 2016hnk
is consistent with being a subluminous (MB = -16.7 mag,
sBV=0.43 ± 0.03), highly reddened object. The IFS of
its host galaxy reveals both a significant amount of dust at the SN
location, residual star formation, and a high proportion of old stellar
populations in the local environment compared to other locations in
the galaxy, which favors an old progenitor for SN 2016hnk. Inspection
of a nebular spectrum obtained one year after maximum contains two
narrow emission lines attributed to the forbidden [Ca II] λλ7291,7324
doublet with a Doppler shift of 700 km s-1. Based on various
observational diagnostics, we argue that the progenitor of SN 2016hnk
was likely a near Chandrasekhar-mass (MCh) carbon-oxygen
white dwarf that produced 0.108 M⊙ of 56Ni. Our
modeling suggests that the narrow [Ca II] features observed in the
nebular spectrum are associated with 48Ca from electron
capture during the explosion, which is expected to occur only in
white dwarfs that explode near or at the MCh limit. Tables C.1-C.7 are also available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr
(ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/cat/J/A+A/630/A76
Title: Spectroscopic classification of SN 2019pqh by NUTS2, and
implications for the claimed association with IceCube-190922B
Authors: Reguitti, A.; Pastorello, A.; Benetti, S.; Cai, Y. -Z.;
Cappellaro, E.; Fiore, A.; Elias-Rosa, N.; Tomasella, L.; Valerin,
G.; Ochner, P.; Morales-Garoffolo, A.; Stritzinger, M.; Holmbo,
S.; Moran, S.; Brennan, S.; Callis, E.; Fraser, M.; Kankare, E.;
Kotak, R.; Kuncarayakti, H.; Heikkila, T.; Mattila, S.; Reynolds,
T.; Lundqvist, P.; Dong, S.; Chen, P.; Bose, S.
Bibcode: 2019ATel13133....1R
Altcode:
The Nordic Optical Telescope (NOT) Unbiased Transient Survey 2 (NUTS2;
Atel #12661) reports the spectroscopic classification of SN 2019pqh
in the host galaxy 2MASX J00262847-0107513.
Title: The Next-Generation Radio Neutrino Observatory —
Multi-Messenger Neutrino Astrophysics at Extreme Energies
Authors: Connolly, Amy; Aguilar, J. A.; Allison, P.; Archambault, S.;
Barnet, S.; Beatty, J. J.; Besson, D. Z.; Botner, O.; Buitink, S.;
Chen, P.; Clark, B. A.; Deaconu, C.; de Kockere, S.; DuVernois, M. A.;
van Eijndhoven, N.; Finley, C.; Garcia, D.; Hallgren, A.; Halzen, F.;
Hanson, J.; Hanson, K.; Haugen, J.; Pérez de los Heros, C.; Hoffman,
K. D.; Hokanson-Fasig, B.; Hughes, K.; Hultqvist, K.; Ishihara, A.;
Karle, A.; Kelley, J. L.; Klein, S. R.; Khandelwal, R.; Kowalski,
M.; Kravchenko, I.; Latif, U. A.; Liu, T. C.; Lu, M. -Y.; Mase, K.;
Morse, R.; Nam, J.; Nelles, A.; Oberla, E.; Pfendner, C.; Pan, Y.;
Plaisier, I.; Prohira, S.; Robertson, S.; Rolla, J.; Ryckbosch, D.;
Schröder, F. G.; Seckel, D.; Shultz, A.; Smith, D.; Southall, D.;
O'Sullivan, E.; Stezelberger, T.; Toscano, S.; Torres-Espinosa, J.;
Unger, S.; Vieregg, A. G.; de Vries, K.; Wang, S. -H.; Welling, C.;
Wissel, S. A.; Yoshida, S.
Bibcode: 2019BAAS...51g.218C
Altcode: 2019arXiv190712526A; 2019astro2020U.218C
RNO is the mid-scale discovery instrument designed to make the first
observation of neutrinos from the cosmos at extreme energies, with
sensitivity well beyond current instrument capabilities. This new
observatory will be the largest ground-based neutrino telescope to date,
enabling the measurement of neutrinos above 10-1⁶ eV.
Title: LIGO/Virgo S190814bv: Pan-STARRS imaging indicates DG19sevhc
(AT2019npy) is a proper motion star
Authors: Smartt, S.; Malesani, D.; Smith, K. W.; Huber, M.;
Chambers, K.; Schulz, A.; Young, D. R.; McBrien, O.; Srivastav,
J. Gillanders. S.; O'Neil, D.; Clark, P.; Sim, S.; de Boer, T.;
Bulger, J.; Fairlamb, J.; Huber, M.; Lin, C. -C.; Lowe, T.; Magnier,
E.; Wainscoat, R. J.; Willman, M.; -W., T.; Chen; Rest, A.; Stubbs, C.
Bibcode: 2019GCN.25386....1S
Altcode:
In the search of the skymap of the NSBH event S190814bv (The LIGO
Scientific Collaboration and the Virgo Collaboration, GCN 25333, 25324)
the DECam-GROWTH team identified DG19sevhc (AT2019npy; Andreoni et
al. GCN 25362) as a candidate. It was followed up by Rossi et al (GCN
25383) and Dichiara et al. (GCN 25374). The latter reported an unusual
and rapid z-band rise, which drew attention. We found a previous source
detection close to this position on difference images taken during
the Pan-STARRS Survey For Transients (Huber et al. 2015, ATel 7153)
at i=20.9, on multiple images from MJD=58335 (2018-08-05). However
closer inspection revealed that the source was not a transient. There
is a faint red star which is coincident with background extended flux
(probably a faint, red galaxy) and the star appears to have slow proper
motion. This produced a dipole source in the Pan-STARRS difference
images, and triggered a new source detection. The motion between the
Pan-STARRS reference and the image from MJD=58335 is visually clear
(about 1.4 arcsec). We further inspected the separate Pan-STARRS
3Pi epochs (Chambers et al. 2016, arXiv:1612.05560C). Using 3 images
with reasonable S/N between 2010 September and 2014 August, plus the
public DECam image from 2019 August, the position of the star traces a
vector towards the S-E. We estimate a proper motion of 0.07 and -0.12
arcsec/yr in RA and Dec, respectively. Hence we conclude that AT2019npy
is not a transient, but resulted from the proper motion of this star
leaving a positive residual in the DECam images of 2019 August, and
the DECam references. The unusual spatial coincidence of the moving
star and background galaxy made the original DECam identification as
a transient quite understandable and reasonable.
Title: A luminous stellar outburst during a long-lasting eruptive
phase first, and then SN IIn 2018cnf
Authors: Pastorello, A.; Reguitti, A.; Morales-Garoffolo, A.; Cano,
Z.; Prentice, S. J.; Hiramatsu, D.; Burke, J.; Kankare, E.; Kotak, R.;
Reynolds, T.; Smartt, S. J.; Bose, S.; Chen, P.; Congiu, E.; Dong,
S.; Geier, S.; Gromadzki, M.; Hsiao, E. Y.; Kumar, S.; Ochner, P.;
Pignata, G.; Tomasella, L.; Wang, L.; Arcavi, I.; Ashall, C.; Callis,
E.; de Ugarte Postigo, A.; Fraser, M.; Hosseinzadeh, G.; Howell,
D. A.; Inserra, C.; Kann, D. A.; Mason, E.; Mazzali, P. A.; McCully,
C.; Rodríguez, Ó.; Phillips, M. M.; Smith, K. W.; Tartaglia, L.;
Thöne, C. C.; Wevers, T.; Young, D. R.; Pumo, M. L.; Lowe, T. B.;
Magnier, E. A.; Wainscoat, R. J.; Waters, C.; Wright, D. E.
Bibcode: 2019A&A...628A..93P
Altcode: 2019arXiv190600814P
We present the results of the monitoring campaign of the Type IIn
supernova (SN) 2018cnf (a.k.a. ASASSN-18mr). It was discovered about
ten days before the maximum light (on MJD = 58 293.4 ± 5.7 in the V
band, with MV = -18.13 ± 0.15 mag). The multiband light
curves show an immediate post-peak decline with some minor luminosity
fluctuations, followed by a flattening starting about 40 days after
maximum. The early spectra are relatively blue and show narrow Balmer
lines with P Cygni profiles. Additionally, Fe II, O I, He I, and Ca
II are detected. The spectra show little evolution with time and with
intermediate-width features becoming progressively more prominent,
indicating stronger interaction of the SN ejecta with the circumstellar
medium. The inspection of archival images from the Panoramic Survey
Telescope and Rapid Response System (Pan-STARRS) survey has revealed
a variable source at the SN position with a brightest detection in
December 2015 at Mr = -14.66 ± 0.17 mag. This was likely
an eruptive phase from the massive progenitor star that started from at
least mid-2011, and that produced the circumstellar environment within
which the star exploded as a Type IIn SN. The overall properties of SN
2018cnf closely resemble those of transients such as SN 2009ip. This
similarity favours a massive hypergiant, perhaps a luminous blue
variable, as progenitor for SN 2018cnf.
Title: The simulation of the sensitivity of the Antarctic Impulsive
Transient Antenna (ANITA) to Askaryan radiation from cosmogenic
neutrinos interacting in the Antarctic Ice
Authors: Cremonesi, L.; Connolly, A.; Allison, P.; Banerjee, O.;
Batten, L.; Beatty, J. J.; Bechtol, K.; Belov, K.; Besson, D. Z.;
Binns, W. R.; Bugaev, V.; Cao, P.; Chen, C. C.; Chen, C. H.; Chen,
P.; Clem, J. M.; Dailey, B.; Deaconu, C.; Dowkontt, P. F.; Fox, B. D.;
Gordon, J. W. H.; Gorham, P. W.; Hill, B.; Huang, J. J.; Hughes, K.;
Hupe, R.; Israel, M. H.; Liewer, K. M.; Lin, S. Y.; Liu, T. C.; Ludwig,
A. B.; Macchiarulo, L.; Matsuno, S.; McBride, K.; Miki, C.; Mulrey, K.;
Nam, J.; Nichol, R. J.; Novikov, A.; Oberla, E.; Prohira, S.; Rauch,
B. F.; Roberts, J. M.; Romero-Wolf, A.; Rotter, B.; Russell, J. W.;
Saltzberg, D.; Seckel, D.; Schoorlemmer, H.; Shiao, J.; Stafford,
S.; Stockham, J.; Stockham, M.; Strutt, B.; Stuhr, J.; Sutherland,
M.; Varner, G. S.; Vieregg, A. G.; Wang, S. H.; Wissel, S. A.
Bibcode: 2019JInst..14P8011C
Altcode: 2019arXiv190311043C
A Monte Carlo simulation program for the radio detection of Ultra
High Energy (UHE) neutrino interactions in the Antarctic ice as viewed
by the Antarctic Impulsive Transient Antenna (ANITA) is described in
this article. The program, icemc, provides an input spectrum of UHE
neutrinos, the parametrization of the Askaryan radiation generated
by their interaction in the ice, and the propagation of the radiation
through ice and air to a simulated model of the third and fourth ANITA
flights. This paper provides an overview of the icemc simulation,
descriptions of the physics models used and of the ANITA electronics
processing chain, data/simulation comparisons to validate the predicted
performance, and a summary of the impact of published results.
Title: LIGO/VIRGO S190814bv: No candidates from Pan-STARRS and
non-detection of AT2019nme
Authors: Huber, M.; Smith, K. W.; Chambers, K.; Schulz, A.; Smartt,
S.; Young, D. R.; McBrien, O.; Srivastav, J. Gillanders. S.; O'Neil,
D.; Clark, P.; Sim, S.; de Boer, T.; Bulger, J.; Fairlamb, J.; Huber,
M.; Lin, C. -C.; Lowe, T.; Magnier, E.; Wainscoat, R. J.; Willman,
M.; -W., T.; Chen; Rest, A.; Stubbs, C.
Bibcode: 2019GCN.25356....1H
Altcode:
We report observations of the LALInference skymap of the NSBH
event S190814bv (The LIGO Scientific Collaboration and the Virgo
Collaboration, 25333, 25324) with the Pan-STARRS1 telescope (Chambers et
al. 2016, arXiv:1612.05560C). Images were taken in the PS1 i and z bands
(Tonry et al. 2012, ApJ 750, 99). Beginning at 2019-08-15 12:40:37 UT
(58710.5282) or 15.5hrs after the detection of S190814bv, observations
started in the i-band. We used the updated LALInference.v1.fits.gz
map for pointing coverage. Observations finished at 2019-08-15
15:13:38 UT. At each pointing position a dithered sequence of 45
sec i-band and z-band images were taken. These were combined into a
single night stack, covering the GPC1 camera chip gaps. These dithered
sequences were repeated, with overlaps, to map 18 square degrees of the
LALInference.v1.gz map 90% credible region, corresponding to a summed
probability 89% of the skymap. We did not cover the smaller probability
blob to the south east at DEC=-32. Conditions were somewhat affected
by clouds, and moon, seeing was around 1.2 - 1.3 arcsec. 5-sigma
limiting magnitudes were around i ~ 20.8 and z ~ 20.3. The images
were processed with the IPP (Magnier et al. 2016, arXiv:1612.05240)
and difference images were produced using the Pan-STARRS1 Science
Consortium 3Pi images as reference frames. Transient candidates
were run through our standard filtering procedures, combined with
a machine learning algorithm (Wright et al. 2015, MNRAS, 449, 451)
were applied and all candidates were spatially cross-matched with
known minor planets, and major star, galaxy, AGN and multi-wavelength
catalogues (as described in Smartt et al. 2016, MNRAS, 462 4094),
and already reported transients in the TNS before S190814by. After
removing these, and requiring detections in BOTH i and z-band stacks,
we were left with two transients. Both of which we discount as possible
counterparts. Name | TNS Name | RA (J2000) | Dec (J2000) | Disc MJD |
i Mag err | z Mag err PS19epf | AT2019noq | 00 48 47.88 | -25 18 23.4 |
58710.58 | 19.93 0.11 | 20.17 0.16 PS19eph | AT2019nor | 00 49 51.99
| -24 16 17.7 | 58710.59 | 19.69 0.07 | 19.55 0.07 PS19epf is within
the inner 20% contour. It is located 0.46"S 3.96"E from the centre of
the galaxy PSO J012.1980-25.3064 (r = 18.3 Kron mag). The host has no
measured photometric or spectroscopic redshift. However there are 4
separate, single night detections in the ZTF public stream, from Lasair
(Smith et al. 2019; https://lasair.roe.ac.uk/object/ZTF19abkhnce/),
across the last 12 days. Hence it is most probably a SN exploding
before the GW. PS19eph is within the inner 10% contour. However it is
coincident with the core of the B=18.67 galaxy 6dF J0049520-241618 at
z = 0.436522 from NED, and hence is not likely related to S190814bv. We
do not recover desgw-190814b (AT2019nme). Reported at i=19.33 z=19.39,
(58710.278) by Soares-Santos et al. GCN 25336. This is on the edge
of our stack, but we estimate a 3-sigma limit of i~20.6 z~20.2. If
it is real, it implies a very fast fade in i-band of 1 mag in about
8hrs. Deeper follow-up is required, and confirmation from the DECam
team if it is real.
Title: Transient Classification Report for 2019-08-07
Authors: Chen, P.; Holoien, T. W. S.; Dong, S.
Bibcode: 2019TNSCR1444....1C
Altcode:
No abstract at ADS
Title: VizieR Online Data Catalog: SN2016hnk photometry and
spectroscopy (Galbany+, 2019)
Authors: Galbany, L.; Ashall, C.; Hoeflich, P.; Gonzalez-Gaitan, S.;
Taubenberger, S.; Stritzinger, M.; Hsiao, E. Y.; Mazzali, P.; Baron,
E.; Blondin, S.; Bose, S.; Bulla, M.; Burke, J. F.; Burns, C. R.;
Cartier, R.; Chen, P.; Della Valle, M.; Diamond, T. R.; Gutierrez,
C. P.; Harmanen, J.; Hiramatsu, D.; Holoien, T. W. -S.; Hosseinzadeh,
G.; Howell, D. A.; Huang, Y.; Inserra, C.; de Jaeger, T.; Jha, S. W.;
Kangas, T.; Kromer, M.; Lyman, J. D.; Maguire, K.; Howie, Marion G.;
Milisavljevic, D.; Prentice, S. J.; Razza, A.; Reynolds, T. M.; Sand,
D. J.; Shappee, B. J.; Shekhar, R.; Smartt, S. J.; Stassun, K. G.;
Sullivan, M.; Valenti, S.; Villanueva, S.; Wang, X.; Craig Wheeler,
J.; Zhai, Q.; Zhang, J.
Bibcode: 2019yCat..36300076G
Altcode:
We present ATLAS photometry in c and o bands, and ASASS-SN V-band
photometry in Tables C1 and C2, respectively. All other photometric
observations and SN magnitudes are given in Tables C3 (optical) and
C4 (NIR) in the AB system. The full spectral log is presented
in Table C5. We highlight a few features in SN 2016hnk that
we characterized in the spectral sequence in terms of the evolution
of their pseudo-equivalent width (pEW) and velocities. We list our
measurements in Tables C6 and C7. (7 data files).
Title: Localizing Putative Methane Sources on Mars from Spacecraft
Observations and Back-Trajectory Modeling Techniques
Authors: Luo, Y.; Mischna, M. A.; Yung, Y. L.; Kleinböhl, A.; Chen, P.
Bibcode: 2019LPICo2089.6057L
Altcode:
We have used back-trajectory modeling techniques to localize the source
of Mars methane plumes detected at Gale crater. Our method simplifies
the localization problem and our first results look promising that
the approach will succeed.
Title: LIGO/Virgo S190728q: Optical transients from Pan-STARRS
coverage during first 2 nights
Authors: Huber, M.; Smith, K. W.; Chambers, K.; Schulz, A.; Smartt,
S. J.; Young, D. R.; McBrien, O.; Gillanders, J.; Srivastav, S.;
O'Neil, D.; Clark, P.; Sim, S.; de Boer, T.; Bulger, J.; Fairlamb,
J.; Huber, M.; Lin, C. -C.; Lowe, T.; Magnier, E.; Wainscoat, R. J.;
Willman, M.; -W., T.; Chen; Rest, A.; Stubbs, C.
Bibcode: 2019GCN.25224....1H
Altcode:
We report observations of the LALInf skymap of the BBH event s190728q
(The LIGO Scientific Collaboration and the Virgo Collaboration, GCN
25208, 25187) with the Pan-STARRS1 telescope (Chambers et al. 2016,
arXiv:1612.05560C). Images were taken in the PS1 w and i-bands
(Tonry et al. 2012, ApJ 750, 99). Beginning at 2019-07-28 10:08:31 UT
(58692.4226) or 3.4hrs after the detection of S190728q, observations
started in the w-band in the standard NEO search sequence. At each
pointing position a sequence of quads (4 x 45 sec) was taken. This
observing sequence ensures exactly the same pointing position for each
of the quads. Observations of the map finished on 2019-07-28 14:44:53
UT. On the following night, beginning at 2019-07-29 08:51:02 a series
of 45sec i-band dithered images were taken to cover the map. We
finished observing at 2019-07-29 10:06:41. In total PS1 covered
105 squ. degrees of the LALInference.offline.fits,gz map of the 90%
credible region and we estimate we covered a sky region totalling 92%
of the event's localisation likelihood. The images were processed with
the IPP (Magnier et al. 2016, arXiv:1612.05240) and difference images
were produced using the Pan-STARRS1 Science Consortium 3Pi images as
reference frames. Transient candidates were run through our standard
filtering procedures, combined with a machine learning algorithm
(Wright et al. 2015, MNRAS, 449, 451) were applied and all candidates
were spatially cross-matched with known minor planets, and major star,
galaxy, AGN and multi-wavelength catalogues (as described in Smartt
et al. 2016, MNRAS, 462 4094). We report the following transients
which are all within the 90% contour of the LALInference.offline.fits
map. They are all supernova like candidates, either offset from a clear
galaxy or no obvious host. The majority of these are detected over
the 2 nights and do not show any fast fading or rising. The redshifts
below are all photometric from SDSS DR15 or GLADE. For reference the
redshift range corresponding to the luminosity distance of S190728q
(GCN 25208) is approximately 0.14 < z < 0.22. Name TNS Name RA
(J2000) Dec (J2000) Disc MJD Disc Mag photoz PS19dxk AT2019lzs 20 42
38.23 +06 05 53.6 58692.43 21.92 w PS19dxc AT2019lzb 20 45 55.34 +02 05
53.5 58692.43 20.62 w 0.464 PS19dxl AT2019lzr 20 47 08.30 +07 16 16.2
58692.43 21.37 w PS19dxb AT2019lzc 20 52 54.72 +02 31 43.6 58692.43
21.69 w 0.228 PS19dwv AT2019lyv 21 00 06.51 +12 16 54.5 58692.53 21.99
w 0.046 PS19dxo AT2019lzv 21 01 02.31 +14 23 48.5 58692.52 20.96 w
PS19dxn AT2019lzt 21 01 13.26 +13 29 39.0 58692.53 21.05 w PS19dxf
AT2019lzg 21 03 16.16 +14 22 50.9 58692.54 20.91 w PS19dxg AT2019lzf
21 11 56.20 +17 14 27.2 58692.58 21.80 w 0.713 PS19dwz AT2019lyz 21
14 09.78 +13 37 04.8 58692.53 21.58 w PS19dxm AT2019lzu 21 26 42.01
+17 17 25.8 58692.58 21.18 w PS19dxe AT2019lzd 21 29 51.15 +19 10
33.6 58692.58 22.10 w 0.090 PS19dxd AT2019lze 21 33 04.06 +21 25 19.2
58692.58 21.77 w The one exception is PS19dxf, which appears to show
a fast rise and decline of 1 mag in 33 minutes in the w-band images of
the first night. This is probably an M-dwarf flare, as it is coincident
with an uncatalogued, red and faint source in both Pan-STARRS and DECaLs
imaging surveys. In Pan-STARRS it is only detected in z. Star-galaxy
distinction is not possible, but a galactic M-dwarf flare is the most
likely explanation for this transient. Confirmation of DECam-GROWTH
objects from Goldstein et al. (GCN 25215) or TNS registered: Name DG
Name RA (J2000) Dec (J2000) Det. MJD Mag TNS Name PS19dwt DG19qukmb 20
44 56.55 +07 23 58.6 58692.43 20.57 w AT2019lyc PS19dwy DG19bfhpb 21
05 58.67 +09 58 43.7 58692.53 21.05 w AT2019lvy PS19dxp DG19tneob 21
15 01.04 +14 59 22.7 58692.58 20.37 w AT2019lxc Other known objects we
recovered but were previously discovered by Pan-STARRS or ZTF: Name RA
(J2000) Dec (J2000) Det. MJD Mag TNS Name PS19dwm 21 34 22.65 +21 20
30.6 58692.58 20.66 w AT2019lxm ZTF19aavndxo 20 47 51.02 +10 17 35.5
58693.38 19.48 i AT2019fyt PS19dxj 21 31 22.91 +20 34 04.4 58692.58
20.95 w AT2019lzo We also note that DG19rxclb as reported in Goldstein
et al. (GCN 25215) is an old object (AT2019jvb) discovered by PS1 and
registered on TNS on 2019-06-01.
Title: High-elevation synoptic radio array for detection of upward
moving air-showers, deployed in the Antarctic mountains
Authors: Nam, J.; Chen, P.; Chen, Y. C.; Hsu, S. Y.; Huang, J. J.;
Huang, M. H. A.; Kuo, C. Y.; Leung, C. H.; Liu, T. C.; Shin, B. K.;
Shiao, Y. S.; Wang, M. Z.; Wang, S. H.; Hornhuber, C.; Novikov, A.
Bibcode: 2019ICRC...36..967N
Altcode: 2019PoS...358..967N
No abstract at ADS
Title: Transient Classification Report for 2019-07-26
Authors: Bose, S.; Holmbo, S.; Mattila, S.; Kankare, E.; Stritzinger,
M.; Heikkila, T.; Chen, P.
Bibcode: 2019TNSCR1332....1B
Altcode:
No abstract at ADS
Title: Recent Results from The Askaryan Radio Array
Authors: ARA Collaboration; Allison, P.; Archambault, S.; Bard, R.;
Beatty, J. J.; Beheler-Amass, M.; Besson, D. Z.; Beydler, M.; Chen,
C. -C.; Chen, C. -H.; Chen, P.; Clark, B.; Clough, A.; Connolly, A.;
Davies, J.; Deaconu, C.; DuVernois, M. A.; Fender, C.; Friedman, E.;
Hanson, J.; Hanson, K.; Haugen, J.; Hoffman, K. D.; Hong, E.; Hsu,
S. -Y.; Hu, L.; Huang, J. -J.; Huang, M. -H.; Ishihara, A.; Karle,
A.; Kelley, J. L.; Khandelwal, R.; Kim, M.; Kravchenko, I.; Kruse,
J.; Kurusu, K.; Landsman, H.; Latif, U. A.; Laundrie, A.; Li, C. -J.;
Liu, T. C.; Lu, M. -Y.; Mase, K.; Meures, T.; Nam, J.; Nichol, R. J.;
Nir, G.; Oberla, E.; O'Murchadha, A.; Pan, Y.; Ratzlaff, K.; Roth,
J.; Sandstrom, P.; Seckel, D.; Shiao, Y. -S.; Shultz, A.; Song, M.;
Touart, J.; Vieregg, A. G.; Wang, M. -Z.; Wang, S. -H.; Wissel, S. A.;
Yoshida, S.; Young, R.
Bibcode: 2019arXiv190711125A
Altcode:
The Askaryan Radio Array (ARA) is an ultra-high energy (UHE) neutrino
telescope at the South Pole consisting of an array of radio antennas
aimed at detecting the Askaryan radiation produced by neutrino
interactions in the ice. Currently, the experiment has five stations
in operation that have been deployed in stages since 2012. This
contribution focuses on the development of a search for a diffuse
flux of neutrinos in two ARA stations (A2 and A3) from 2013-2016. A
background of $\sim 0.01-0.02$ events is expected in one station in each
of two search channels in horizontal- and vertical-polarizations. The
expected new constraints on the flux of ultra-high energy neutrinos
based on four years of analysis with two stations improve on the
previous limits set by ARA by a factor of about two. The projected
sensitivity of ARA's five-station dataset is beginning to be competitive
with other neutrino telescopes at high energies near $10^{10.5}\,$GeV.
Title: Transient Classification Report for 2019-07-21
Authors: Chen, P.; Dong, S.; Gromadzki, M.; Buckley, D. A. H.
Bibcode: 2019TNSCR1296....1C
Altcode:
No abstract at ADS
Title: Spectroscopic classification of two ASAS-SN supernovae
with SALT
Authors: Chen, P.; Dong, S.; Gromadzki, M.; Buckley, D. A. H.
Bibcode: 2019TNSAN..49....1C
Altcode:
We report classification for two ASAS-SN supernovae
(ASASSN-19qr/2019khf, ASASSN-19qw/2019knt) as SNe Ia.
Title: Spectroscopic observation of AT2019lls and SN2019lqo by NUTS
(NOT Un-biased Transient Survey)
Authors: Bose, S.; Holmbo, S.; Mattila, S.; Kankare, E.; Stritzinger,
M.; Heikkila, Teppo; Chen, P.
Bibcode: 2019ATel12961....1B
Altcode:
The Nordic Optical Telescope (NOT) Unbiased Transient Survey (NUTS; ATel
#8992) reports the spectroscopic classification of optical transients
2019lls (MASTEROT J203053.79+384020.1) and 2019lqo (Gaia19dcu; in the
luminous infrared galaxy Arp 299).
Title: ASAS-SN Transient Classification Report for 2019-07-12
Authors: Bose, S.; Dong, S.; Chen, P.; Stanek, K. Z.; Prieto, J. L.;
Shields, J.
Bibcode: 2019TNSCR1191....1B
Altcode:
No abstract at ADS
Title: Design and performance of an interferometric trigger array
for radio detection of high-energy neutrinos
Authors: Allison, P.; Archambault, S.; Bard, R.; Beatty, J. J.;
Beheler-Amass, M.; Besson, D. Z.; Beydler, M.; Bogdan, M.; Chen,
C. -C.; Chen, C. -H.; Chen, P.; Clark, B. A.; Clough, A.; Connolly, A.;
Cremonesi, L.; Davies, J.; Deaconu, C.; DuVernois, M. A.; Friedman, E.;
Hanson, J.; Hanson, K.; Haugen, J.; Hoffman, K. D.; Hokanson-Fasig,
B.; Hong, E.; Hsu, S. -Y.; Hu, L.; Huang, J. -J.; Huang, M. -H.;
Hughes, K.; Ishihara, A.; Karle, A.; Kelley, J. L.; Khandelwal, R.;
Kim, M.; Kravchenko, I.; Kruse, J.; Kurusu, K.; Landsman, H.; Latif,
U. A.; Laundrie, A.; Li, C. -J.; Liu, T. C.; Lu, M. -Y.; Ludwig,
A.; Mase, K.; Meures, T.; Nam, J.; Nichol, R. J.; Nir, G.; Oberla,
E.; ÓMurchadha, A.; Pan, Y.; Pfendner, C.; Ransom, M.; Ratzlaff,
K.; Roth, J.; Sandstrom, P.; Seckel, D.; Shiao, Y. -S.; Shultz, A.;
Smith, D.; Song, M.; Sullivan, M.; Touart, J.; Vieregg, A. G.; Wang,
M. -Z.; Wang, S. -H.; Wei, K.; Wissel, S. A.; Yoshida, S.; Young, R.
Bibcode: 2019NIMPA.930..112A
Altcode: 2018arXiv180904573A
Ultra-high energy neutrinos are detectable through impulsive radio
signals generated through interactions in dense media, such as
ice. Subsurface in-ice radio arrays are a promising way to advance the
observation and measurement of astrophysical high-energy neutrinos
with energies above those discovered by the IceCube detector (≥ 1
PeV) as well as cosmogenic neutrinos created in the GZK process (≥
100 PeV). Here we describe the NuPhase detector, which is a compact
receiving array of low-gain antennas deployed 185 m deep in glacial
ice near the South Pole. Signals from the antennas are digitized
and coherently summed into multiple beams to form a low-threshold
interferometric phased array trigger for radio impulses. The NuPhase
detector was installed at an Askaryan Radio Array (ARA) station
during the 2017/18 Austral summer season. In situ measurements with
an impulsive, point-source calibration instrument show a 50% trigger
efficiency on impulses with voltage signal-to-noise ratios (SNR)
of ≤2.0, a factor of ∼1.8 improvement in SNR over the standard
ARA combinatoric trigger. Hardware-level simulations, validated with
in situ measurements, predict a trigger threshold of an SNR as low
as 1.6 for neutrino interactions that are in the far field of the
array. With the already-achieved NuPhase trigger performance included
in ARASim, a detector simulation for the ARA experiment, we find the
trigger-level effective detector volume is increased by a factor of 1.8
at neutrino energies between 10 and 100 PeV compared to the currently
used ARA combinatoric trigger. We also discuss an achievable near term
path toward lowering the trigger threshold further to an SNR of 1.0,
which would increase the effective single-station volume by more than
a factor of 3 in the same range of neutrino energies.
Title: Constraints on the ultrahigh-energy cosmic neutrino flux from
the fourth flight of ANITA
Authors: Gorham, P. W.; Allison, P.; Banerjee, O.; Batten, L.; Beatty,
J. J.; Belov, K.; Besson, D. Z.; Binns, W. R.; Bugaev, V.; Cao, P.;
Chen, C. H.; Chen, P.; Chen, Y.; Clem, J. M.; Connolly, A.; Cremonesi,
L.; Dailey, B.; Deaconu, C.; Dowkontt, P. F.; Fox, B. D.; Gordon,
J. W. H.; Hast, C.; Hill, B.; Hsu, S. Y.; Huang, J. J.; Hughes, K.;
Hupe, R.; Israel, M. H.; Liewer, K. M.; Liu, T. C.; Ludwig, A. B.;
Macchiarulo, L.; Matsuno, S.; McBride, K.; Miki, C.; Mulrey, K.; Nam,
J.; Naudet, C.; Nichol, R. J.; Novikov, A.; Oberla, E.; Prohira, S.;
Rauch, B. F.; Ripa, J.; Roberts, J. M.; Romero-Wolf, A.; Rotter, B.;
Russell, J. W.; Saltzberg, D.; Seckel, D.; Schoorlemmer, H.; Shiao,
J.; Stafford, S.; Stockham, J.; Stockham, M.; Strutt, B.; Sutherland,
M. S.; Varner, G. S.; Vieregg, A. G.; Wang, N.; Wang, S. H.; Wissel,
S. A.; Anita Collaboration
Bibcode: 2019PhRvD..99l2001G
Altcode: 2019arXiv190204005G
The ANtarctic Impulsive Transient Antenna (ANITA) NASA long-duration
balloon payload completed its fourth flight in December 2016, after
28 days of flight time. ANITA is sensitive to impulsive broadband
radio emission from interactions of ultrahigh-energy neutrinos
in polar ice (Askaryan emission). We present the results of two
separate blind analyses searching for signals from Askaryan emission
in the data from the fourth flight of ANITA. The more sensitive
analysis, with a better expected limit, has a background estimate
of 0.64-0.45+0.69 and an analysis efficiency
of 82 ±2 %. The second analysis has a background estimate of
0.34-0.16+0.66 and an analysis efficiency of 71
±6 %. Each analysis found one event in the signal region, consistent
with the background estimate for each analysis. The resulting limit
further tightens the constraints on the diffuse flux of ultrahigh-energy
neutrinos at energies above 1 019.5 eV .
Title: VizieR Online Data Catalog: SN 2017jfs optical and NIR light
curves (Pastorello+, 2019)
Authors: Pastorello, A.; Chen, T. -W.; Cai, Y. -Z.; Morales-Garoffolo,
A.; Cano, Z.; Mason, E.; Barsukova, E. A.; Benetti, S.; Berton, M.;
Bose, S.; Bufano, F.; Callis, E.; Cannizzaro, G.; Cartier, R.; Chen,
P.; Dong, S.; Dyrbye, S.; Elias-Rosa, N.; Floers, A.; Fraser, M.;
Geier, S.; Goranskij, V. P.; Kann, D. A.; Kuncarayakti, H.; Onori,
F.; Reguitti, A.; Reynolds, T.; Losada, I. R.; Sagues Carracedo,
A.; Schweyer, T.; Smartt, S. J.; Tatarnikov, A. M.; Valeev, A. F.;
Vogl, C.; Wevers, T.; de Ugarte Postigo, A.; Izzo, L.; Inserra, C.;
Kankare, E.; Maguire, K.; Smith, K. W.; Stalder, B.; Tartaglia, L.;
Thoene, C. C.; Valerin, G.; Young, D. R.
Bibcode: 2019yCat..36259008P
Altcode:
Optical and NIR photometry of AT 2017jfs: Johnson-Bessell B,V (Vega
system), Sloan u,g,r,i,z (AB system) and J,H,K (Vega system). (1
data file).
Title: Kinematics and Energetics of the EUV Waves on 11 April 2013
Authors: Fulara, Aarti; Chandra, Ramesh; Chen, P. F.; Zhelyazkov,
Ivan; Srivastava, A. K.; Uddin, Wahab
Bibcode: 2019SoPh..294...56F
Altcode: 2019arXiv190312158F
In this study, we present the observations of extreme-ultraviolet
(EUV) waves associated with an M6.5 flare on 2013 April 11. The event
was observed by Solar Dynamics Observatory (SDO) in different EUV
channels. The flare was also associated with a halo CME and type
II radio bursts. We observed both fast and slow components of the
EUV wave. The speed of the fast component, which is identified
as a fast-mode MHD wave, varies in the range from 600 to 640
kms−1, whereas the speed of the slow-component is
≈140 kms−1. We observed the unusual phenomenon that,
as the fast-component EUV wave passes through two successive magnetic
quasi-separatrix layers (QSLs), two stationary wave fronts are formed
locally. We propose that part of the outward-propagating fast-mode
EUV wave is converted into slow-mode magnetohydrodynamic waves, which
are trapped in local magnetic field structures, forming successive
stationary fronts. Along the other direction, the fast-component EUV
wave also creates oscillations in a coronal loop lying ≈225 Mm away
from the flare site. We have computed the energy of the EUV wave to
be of the order of 1020J.
Title: DuPont spectroscopy reveals ASASSN-19nb (SN 2019fmr) and
ASASSN-19nd (SN 2019fpc) are type-Ia supernovae
Authors: Stritzinger, M.; Holmbo, S.; Morrell, N.; Chen, P.; Bose,
S.; Dong, S.; Vallely, P. J.
Bibcode: 2019ATel12792....1S
Altcode:
We report spectra (range 380-924 nm) obtained of ASASSN-19nb (SN
2019fmr) and ASASSN-19nd (SN 2019fpc) with the Las Campanas Observatory
DuPont telescope (+ WFCCD) on May 22.3 and 22.4 UT, respectively.
Title: The relative specific Type Ia supernovae rate from three
years of ASAS-SN
Authors: Brown, J. S.; Stanek, K. Z.; Holoien, T. W. -S.; Kochanek,
C. S.; Shappee, B. J.; Prieto, J. L.; Dong, S.; Chen, P.; Thompson,
Todd A.; Beacom, J. F.; Stritzinger, M. D.; Bersier, D.; Brimacombe, J.
Bibcode: 2019MNRAS.484.3785B
Altcode: 2019MNRAS.tmp..255B; 2018arXiv181000011B
We analyse the 476 SN Ia host galaxies from the All-Sky Automated
Survey for Supernova (ASAS-SN) Bright Supernova Catalogues to determine
the observed relative Type Ia supernova (SN) rates as a function of
luminosity and host galaxy properties. We find that the luminosity
distribution of the SNe Ia in our sample is reasonably well described
by a Schechter function with a faint-end slope α ≈ 1.5 and a knee
M⋆ ≈ -18.0. Our specific SN Ia rates are consistent
with previous results but extend to far lower host galaxy masses. We
find an overall rate that scales as (M⋆/1010
M⊙)α with α ≈ -0.5. This shows that the
specific SN Ia rate continues rising towards lower masses even in
galaxies as small as log (M⋆/M⊙) ≲ 7.0,
where it is enhanced by a factor of ∼10-20 relative to host galaxies
with stellar masses ∼1010 M⊙. We find no
strong dependence of the specific SN Ia rate on the star formation
activity of the host galaxies, but additional observations are required
to improve the constraints on the star formation rates.
Title: Response of the ionosphere to the total solar eclipse on
August 21, 2017 in the United States
Authors: Chen, Peng; Liu, Hang; Zheng, Naiquan; Schmidt, Michael
Bibcode: 2019EGUGA..2113757C
Altcode:
The total solar eclipse crossing the United States from west to east on
August 21, 2017 provided a good opportunity to study the variation of
the ionosphere during a solar eclipse. In this presentation we use US
CORS GNSS data, ionosonde foF2 data and Millstone Hill ISR Ne data to
analyze the response of the ionosphere to the total solar eclipse. The
average value of one day before and one day after the eclipse was
used as a reference value, and the absolute change and the change
relative to the reference value were calculated. Results show that
the vertical total electron content (VTEC) of the ionosphere begins
to decrease after the solar eclipse. The region of the decrease of
VTEC moves with the solar eclipse towards the southeast. The maximum
decrease is close to 10 TECU, the relative change is nearly 50%. The
region with the largest decrease does not coincide with the center of
the total solar eclipse, but is located in the west of the center,
indicating that the ionosphere has a delayed response to the solar
eclipse. The absolute change of VTEC is more obvious on the south side
of the total solar eclipse path, while the relative change is not much
different on the north and south side, and decreasing with the increase
of the distance from the path of the total solar eclipse. Results of
ISR Ne show that there are significant differences in the variation
of Ne at different heights. The Ne above 200 km is 60% lower than the
reference value for up to 6 hours, while below 200 km it is only 10%
lower for a time span of only 2 hours. The foF2 of the four ionosonde
stations shows obviously also the solar eclipse response. It begins
to decrease one hour after the solar eclipse, and reaches its maximum
one hour after the maximum of the solar eclipse, then it gradually
increases and exceeds the reference value.
Title: NUTS2 spectroscopic classification of ASASSN-19jy (AT2019dke)
as a young Type II supernova
Authors: Holmbo, S.; Stritzinger, M.; Nowack, G.; Vallely, S. P.;
Stanek, K.; Elias-Rosa, N.; Kankare, E.; Heikkilä, T.; Kotak, R.;
Kuncarayakti, H.; Mattila, S.; Reynolds, T.; Lundqvist, P.; Ergon,
M.; Pastorello, A.; Benetti, S.; Reguitti, A.; Fiore, A.; Valerin,
G.; Cai, Y. -Z.; Fraser, M.; Moran, S.; Dong, S.; Chen, P.; Bose,
A.; Albrecht, S.; NUTS2 Collaboration
Bibcode: 2019ATel12661....1H
Altcode:
We report on the spectroscopic classification of ASASSN-19jy (AT2019dke,
ATEL#12657) located in ESO 507-G 042 and discovered by the All Sky
Automated Survey for SuperNovae (ASAS-SN; Shappee et al. 2014).
Title: Erratum: “Observations of Turbulent Magnetic
Reconnection within a Solar Current Sheet” (2018, ApJ, 866, 64)
Authors: Cheng, X.; Li, Y.; Wan, L. F.; Ding, M. D.; Chen, P. F.;
Zhang, J.; Liu, J. J.
Bibcode: 2019ApJ...874..108C
Altcode:
No abstract at ADS
Title: First Unambiguous Imaging of Large-scale Quasi-periodic
Extreme-ultraviolet Wave or Shock
Authors: Shen, Yuandeng; Chen, P. F.; Liu, Ying D.; Shibata, Kazunari;
Tang, Zehao; Liu, Yu
Bibcode: 2019ApJ...873...22S
Altcode: 2019arXiv190108199S
We report the first unambiguous quasi-periodic large-scale
extreme-ultraviolet (EUV) wave or shock that was detected by
the Atmospheric Imaging Assembly on board the Solar Dynamics
Observatory. During the whip-like unwinding eruption of a small
filament on 2012 April 24, multiple consecutive large-scale wavefronts
emanating from AR11467 were observed simultaneously along the solar
surface and a closed transequatorial loop system. In the meantime,
an upward propagating dome-shaped wavefront was also observed, whose
initial speed and deceleration are about 1392 km s-1
and 1.78 km s-2, respectively. Along the solar surface,
the quasi-peridoic wavefronts had a period of about 163 ± 21 s and
propagated at a nearly constant speed of 747 ± 26 km s-1
they interacted with active region AR11469 and launched a sympathetic
upward propagating secondary EUV wave. The wavefronts along the loop
system propagated at a speed of 897 km s-1, and they were
reflected back at the southern end of the loop system at a similar
speed. In addition to the propagating waves, a standing kink wave was
also present in the loop system simultaneously. Periodicity analysis
reveals that the period of the wavefronts was consistent with that of
the unwinding helical structures of the erupting filament. Based on
these observational facts, we propose that the observed quasi-periodic
EUV wavefronts were most likely excited by the periodic unwinding
motion of the filament helical structures. In addition, two different
seismological methods are applied to derive the magnetic field strength
of the loop system, and for the first time the reliability of these
inversion techniques are tested with the same magnetic structure.
Title: Flaring, Dust Formation, And Shocks In The Very Slow Nova
ASASSN-17pf (LMCN 2017-11a)
Authors: Aydi, E.; Chomiuk, L.; Strader, J.; Swihart, S. J.; Bahramian,
A.; Harvey, E. J.; Britt, C. T.; Buckley, D. A. H.; Chen, P.; Dage,
K.; Darnley, M. J.; Dong, S.; Hambsch, F-J.; Holoien, T. W. -S.; Jha,
S. W.; Kochanek, C. S.; Kuin, N. P. M.; Li, K. L.; Monard, L. A. G.;
Mukai, K.; Page, K. L.; Prieto, J. L.; Richardson, N. D.; Shappee,
B. J.; Shishkovsky, L.; Sokolovsky, K. V.; Stanek, K. Z.; Thompson, T.
Bibcode: 2019arXiv190309232A
Altcode:
We present a detailed study of the 2017 eruption of the classical nova
ASASSN-17pf (LMCN 2017-11a), which is located in the Large Magellanic
Cloud, including data from AAVSO, ASAS-SN, SALT, SMARTS, SOAR, and the
Neil Gehrels \textit{Swift} Observatory. The optical light-curve is
characterized by multiple maxima (flares) on top of a slowly evolving
light-curve (with a decline time, $t_2>$ 100 d). The maxima correlate
with the appearance of new absorption line systems in the optical
spectra characterized by increasing radial velocities. We suggest that
this is evidence of multiple episodes of mass-ejection with increasing
expansion velocities. The line profiles in the optical spectra indicate
very low expansion velocities (FWHM $\sim$ 190 km s$^{-1}$), making
this nova one of the slowest expanding ever observed, consistent
with the slowly evolving light-curve. The evolution of the colors and
spectral energy distribution show evidence of decreasing temperatures
and increasing effective radii for the pseudo-photosphere during each
maximum. The optical and infrared light-curves are consistent with dust
formation 125 days post-discovery. We speculate that novae showing
several optical maxima have multiple mass-ejection episodes leading
to shocks that may drive $\gamma$-ray emission and dust formation.
Title: Comprehensive analysis of anomalous ANITA events disfavors
a diffuse tau-neutrino flux origin
Authors: Romero-Wolf, A.; Wissel, S. A.; Schoorlemmer, H.; Carvalho,
W. R.; Alvarez-Muñiz, J.; Zas, E.; Allison, P.; Banerjee, O.;
Batten, L.; Beatty, J. J.; Bechtol, K.; Belov, K.; Besson, D. Z.;
Binns, W. R.; Bugaev, V.; Cao, P.; Chen, C. C.; Chen, C. H.; Chen,
P.; Clem, J. M.; Connolly, A.; Cremonesi, L.; Dailey, B.; Deaconu,
C.; Dowkontt, P. F.; Fox, B. D.; Gordon, J. W. H.; Gorham, P. W.;
Hast, C.; Hill, B.; Hsu, S. Y.; Huang, J. J.; Hughes, K.; Hupe, R.;
Israel, M. H.; Liewer, K. M.; Liu, T. C.; Ludwig, A. B.; Macchiarulo,
L.; Matsuno, S.; Miki, C.; Mulrey, K.; Nam, J.; Naudet, C.; Nichol,
R. J.; Novikov, A.; Oberla, E.; Prohira, S.; Rauch, B. F.; Roberts,
J. M.; Rotter, B.; Russell, J. W.; Saltzberg, D.; Seckel, D.; Shiao,
J.; Stafford, S.; Stockham, J.; Stockham, M.; Strutt, B.; Sutherland,
M. S.; Varner, G. S.; Vieregg, A. G.; Wang, S. H.
Bibcode: 2019PhRvD..99f3011R
Altcode: 2018arXiv181107261R
Recently, the ANITA collaboration reported on two upward-going
extensive air shower events consistent with a primary particle that
emerges from the surface of the Antarctic ice sheet. These events may
be of ντ origin, in which the neutrino interacts within
the Earth to produce a τ lepton that emerges from the Earth, decays
in the atmosphere, and initiates an extensive air shower. In this
paper we estimate an upper bound on the ANITA acceptance to a diffuse
ντ flux detected via τ -lepton-induced air showers within
the bounds of standard model uncertainties. By comparing this estimate
with the acceptance of Pierre Auger Observatory and IceCube and assuming
standard model interactions, we conclude that a ντ origin
of these events would imply a neutrino flux at least two orders of
magnitude above current bounds.
Title: Measurement of the real dielectric permittivity ɛr
of glacial ice
Authors: Allison, P.; Archambault, S.; Auffenberg, J.; Bard, R.;
Beatty, J. J.; Beheler-Amass, M.; Besson, D. Z.; Beydler, M.; Chen,
C. C.; Chen, C. H.; Chen, P.; Christenson, A.; Clark, B. A.; Connolly,
A.; Cremonesi, L.; Deaconu, C.; Duvernois, M.; Friedman, L.; Gaior,
R.; Hanson, J.; Hanson, K.; Haugen, J.; Hoffman, K. D.; Hong, E.; Hsu,
S. Y.; Hu, L.; Huang, J. J.; Huang, M. -H. A.; Ishihara, A.; Karle, A.;
Kelley, J. L.; Khandelwal, R.; Kim, M. -C.; Kravchenko, I.; Kruse, J.;
Kurusu, K.; Kuwabara, T.; Landsman, H.; Latif, U. A.; Laundrie, A.;
Li, C. -J.; Liu, T. -C.; Lu, M. -Y.; Mase, K.; Meures, T.; Nam, J.;
Nichol, R. J.; Nir, G.; Novikov, A.; Oberla, E.; O'Murchadha, A.; Pan,
Y.; Pfendner, C.; Ratzlaff, K.; Relich, M.; Roth, J.; Sandstrom, P.;
Seckel, D.; Shiao, Y. S.; Shultz, A.; Song, M.; Touart, J.; Varner,
G. S.; Vieregg, A.; Wang, M. Z.; Wang, S. H.; Wissel, S.; Yoshida,
S.; Young, R.
Bibcode: 2019APh...108...63A
Altcode:
Owing to their small interaction cross-section, neutrinos are
unparalleled astronomical tracers. Ultra-high energy (UHE; E > 10
PeV) neutrinos probe the most distant, most explosive sources in the
Universe, often obscured to optical telescopes. Radio-frequency (RF)
detection of Askaryan radiation in cold polar ice is currently regarded
as the best experimental measurement technique for UHE neutrinos,
provided the RF properties of the ice target can be well-understood. To
that end, the Askaryan Radio Array (ARA) experiment at the South
Pole has used long-baseline RF propagation to extract information
on the index-of-refraction (n =√{ɛr}) in South Polar
ice. Owing to the increasing ice density over the upper 150-200 m,
rays are measured along two, nearly parallel paths, one of which
refracts through an inflection point, with differences in both arrival
time and arrival angle that can be used to constrain the neutrino
properties. We also observe (first) indications for RF ice birefringence
for signals propagating along predominantly horizontal trajectories,
corresponding to an asymmetry of order 0.1% between the ordinary and
extra-ordinary birefringent axes, numerically compatible with previous
measurements of birefringent asymmetries for vertically-propagating
radio-frequency signals at South Pole. Qualitatively, these effects
offer the possibility of redundantly measuring the range from receiver
to a neutrino interaction in Antarctic ice, if receiver antennas are
deployed at shallow (z ∼ -25 m) depths. Such range information is
essential in determining both the neutrino energy, as well as the
incident neutrino direction.
Title: Transient Classification Report for 2019-02-03
Authors: Dong, S.; Bose, S.; Chen, P.; Morrell, N.; Phillips, M.;
Kollmeier, J.
Bibcode: 2019TNSCR.198....1D
Altcode:
No abstract at ADS
Title: Photometric and Spectroscopic Properties of Type Ia Supernova
2018oh with Early Excess Emission from the Kepler 2 Observations
Authors: Li, W.; Wang, X.; Vinkó, J.; Mo, J.; Hosseinzadeh, G.; Sand,
D. J.; Zhang, J.; Lin, H.; PTSS/TNTS; Zhang, T.; Wang, L.; Zhang, J.;
Chen, Z.; Xiang, D.; Rui, L.; Huang, F.; Li, X.; Zhang, X.; Li, L.;
Baron, E.; Derkacy, J. M.; Zhao, X.; Sai, H.; Zhang, K.; Wang, L.; LCO;
Howell, D. A.; McCully, C.; Arcavi, I.; Valenti, S.; Hiramatsu, D.;
Burke, J.; KEGS; Rest, A.; Garnavich, P.; Tucker, B. E.; Narayan, G.;
Shaya, E.; Margheim, S.; Zenteno, A.; Villar, A.; UCSC; Dimitriadis,
G.; Foley, R. J.; Pan, Y. -C.; Coulter, D. A.; Fox, O. D.; Jha,
S. W.; Jones, D. O.; Kasen, D. N.; Kilpatrick, C. D.; Piro, A. L.;
Riess, A. G.; Rojas-Bravo, C.; ASAS-SN; Shappee, B. J.; Holoien,
T. W. -S.; Stanek, K. Z.; Drout, M. R.; Auchettl, K.; Kochanek,
C. S.; Brown, J. S.; Bose, S.; Bersier, D.; Brimacombe, J.; Chen,
P.; Dong, S.; Holmbo, S.; Muñoz, J. A.; Mutel, R. L.; Post, R. S.;
Prieto, J. L.; Shields, J.; Tallon, D.; Thompson, T. A.; Vallely,
P. J.; Villanueva, S., Jr.; Pan-STARRS; Smartt, S. J.; Smith, K. W.;
Chambers, K. C.; Flewelling, H. A.; Huber, M. E.; Magnier, E. A.;
Waters, C. Z.; Schultz, A. S. B.; Bulger, J.; Lowe, T. B.; Willman,
M.; Konkoly/Texas; Sárneczky, K.; Pál, A.; Wheeler, J. C.; Bódi,
A.; Bognár, Zs.; Csák, B.; Cseh, B.; Csörnyei, G.; Hanyecz, O.;
Ignácz, B.; Kalup, Cs.; Könyves-Tóth, R.; Kriskovics, L.; Ordasi,
A.; Rajmon, I.; Sódor, A.; Szabó, R.; Szakáts, R.; Zsidi, G.;
Arizona, University of; Milne, P.; Andrews, J. E.; Smith, N.; Bilinski,
C.; Swift; Brown, P. J.; ePESSTO; Nordin, J.; Williams, S. C.; Galbany,
L.; Palmerio, J.; Hook, I. M.; Inserra, C.; Maguire, K.; Cartier,
Régis; Razza, A.; Gutiérrez, C. P.; North Carolina, University of;
Hermes, J. J.; Reding, J. S.; Kaiser, B. C.; ATLAS; Tonry, J. L.;
Heinze, A. N.; Denneau, L.; Weiland, H.; Stalder, B.; K2 Mission Team;
Barentsen, G.; Dotson, J.; Barclay, T.; Gully-Santiago, M.; Hedges,
C.; Cody, A. M.; Howell, S.; Kepler Spacecraft Team; Coughlin, J.;
Van Cleve, J. E.; Cardoso, J. Vinícius de Miranda; Larson, K. A.;
McCalmont-Everton, K. M.; Peterson, C. A.; Ross, S. E.; Reedy, L. H.;
Osborne, D.; McGinn, C.; Kohnert, L.; Migliorini, L.; Wheaton, A.;
Spencer, B.; Labonde, C.; Castillo, G.; Beerman, G.; Steward, K.;
Hanley, M.; Larsen, R.; Gangopadhyay, R.; Kloetzel, R.; Weschler,
T.; Nystrom, V.; Moffatt, J.; Redick, M.; Griest, K.; Packard, M.;
Muszynski, M.; Kampmeier, J.; Bjella, R.; Flynn, S.; Elsaesser, B.
Bibcode: 2019ApJ...870...12L
Altcode: 2018arXiv181110056L
Supernova (SN) 2018oh (ASASSN-18bt) is the first spectroscopically
confirmed Type Ia supernova (SN Ia) observed in the Kepler
field. The Kepler data revealed an excess emission in its early
light curve, allowing us to place interesting constraints on its
progenitor system. Here we present extensive optical, ultraviolet,
and near-infrared photometry, as well as dense sampling of optical
spectra, for this object. SN 2018oh is relatively normal in its
photometric evolution, with a rise time of 18.3 ± 0.3 days and Δm
15(B) = 0.96 ± 0.03 mag, but it seems to have bluer B -
V colors. We construct the “UVOIR” bolometric light curve having
a peak luminosity of 1.49 × 1043 erg s-1,
from which we derive a nickel mass as 0.55 ± 0.04 M ⊙
by fitting radiation diffusion models powered by centrally located
56Ni. Note that the moment when nickel-powered luminosity
starts to emerge is +3.85 days after the first light in the Kepler
data, suggesting other origins of the early-time emission, e.g.,
mixing of 56Ni to outer layers of the ejecta or interaction
between the ejecta and nearby circumstellar material or a nondegenerate
companion star. The spectral evolution of SN 2018oh is similar to that
of a normal SN Ia but is characterized by prominent and persistent
carbon absorption features. The C II features can be detected from the
early phases to about 3 weeks after the maximum light, representing the
latest detection of carbon ever recorded in an SN Ia. This indicates
that a considerable amount of unburned carbon exists in the ejecta of
SN 2018oh and may mix into deeper layers.
Title: K2 Observations of SN 2018oh Reveal a Two-component Rising
Light Curve for a Type Ia Supernova
Authors: Dimitriadis, G.; Foley, R. J.; Rest, A.; Kasen, D.; Piro,
A. L.; Polin, A.; Jones, D. O.; Villar, A.; Narayan, G.; Coulter,
D. A.; Kilpatrick, C. D.; Pan, Y. -C.; Rojas-Bravo, C.; Fox, O. D.;
Jha, S. W.; Nugent, P. E.; Riess, A. G.; Scolnic, D.; Drout, M. R.;
K2 Mission Team; Barentsen, G.; Dotson, J.; Gully-Santiago, M.; Hedges,
C.; Cody, A. M.; Barclay, T.; Howell, S.; KEGS; Garnavich, P.; Tucker,
B. E.; Shaya, E.; Mushotzky, R.; Olling, R. P.; Margheim, S.; Zenteno,
A.; Kepler spacecraft Team; Coughlin, J.; Van Cleve, J. E.; Cardoso,
J. Vinícius de Miranda; Larson, K. A.; McCalmont-Everton, K. M.;
Peterson, C. A.; Ross, S. E.; Reedy, L. H.; Osborne, D.; McGinn,
C.; Kohnert, L.; Migliorini, L.; Wheaton, A.; Spencer, B.; Labonde,
C.; Castillo, G.; Beerman, G.; Steward, K.; Hanley, M.; Larsen, R.;
Gangopadhyay, R.; Kloetzel, R.; Weschler, T.; Nystrom, V.; Moffatt,
J.; Redick, M.; Griest, K.; Packard, M.; Muszynski, M.; Kampmeier,
J.; Bjella, R.; Flynn, S.; Elsaesser, B.; Pan-STARRS; Chambers,
K. C.; Flewelling, H. A.; Huber, M. E.; Magnier, E. A.; Waters,
C. Z.; Schultz, A. S. B.; Bulger, J.; Lowe, T. B.; Willman, M.;
Smartt, S. J.; Smith, K. W.; DECam; Points, S.; Strampelli, G. M.;
ASAS-SN; Brimacombe, J.; Chen, P.; Muñoz, J. A.; Mutel, R. L.;
Shields, J.; Vallely, P. J.; Villanueva, S., Jr.; PTSS/TNTS; Li,
W.; Wang, X.; Zhang, J.; Lin, H.; Mo, J.; Zhao, X.; Sai, H.; Zhang,
X.; Zhang, K.; Zhang, T.; Wang, L.; Zhang, J.; Baron, E.; DerKacy,
J. M.; Li, L.; Chen, Z.; Xiang, D.; Rui, L.; Wang, L.; Huang, F.;
Li, X.; Cumbres Observatory, Las; Hosseinzadeh, G.; Howell, D. A.;
Arcavi, I.; Hiramatsu, D.; Burke, J.; Valenti, S.; ATLAS; Tonry,
J. L.; Denneau, L.; Heinze, A. N.; Weiland, H.; Stalder, B.; Konkoly;
Vinkó, J.; Sárneczky, K.; Pál, A.; Bódi, A.; Bognár, Zs.; Csák,
B.; Cseh, B.; Csörnyei, G.; Hanyecz, O.; Ignácz, B.; Kalup, Cs.;
Könyves-Tóth, R.; Kriskovics, L.; Ordasi, A.; Rajmon, I.; Sódor,
A.; Szabó, R.; Szakáts, R.; Zsidi, G.; ePESSTO; Williams, S. C.;
Nordin, J.; Cartier, R.; Frohmaier, C.; Galbany, L.; Gutiérrez,
C. P.; Hook, I.; Inserra, C.; Smith, M.; Arizona, University of;
Sand, D. J.; Andrews, J. E.; Smith, N.; Bilinski, C.
Bibcode: 2019ApJ...870L...1D
Altcode: 2018arXiv181110061D
We present an exquisite 30 minute cadence Kepler (K2) light curve of
the Type Ia supernova (SN Ia) 2018oh (ASASSN-18bt), starting weeks
before explosion, covering the moment of explosion and the subsequent
rise, and continuing past peak brightness. These data are supplemented
by multi-color Panoramic Survey Telescope (Pan-STARRS1) and Rapid
Response System 1 and Cerro Tololo Inter-American Observatory 4 m
Dark Energy Camera (CTIO 4-m DECam) observations obtained within hours
of explosion. The K2 light curve has an unusual two-component shape,
where the flux rises with a steep linear gradient for the first few
days, followed by a quadratic rise as seen for typical supernovae
(SNe) Ia. This “flux excess” relative to canonical SN Ia behavior
is confirmed in our i-band light curve, and furthermore, SN 2018oh is
especially blue during the early epochs. The flux excess peaks 2.14 ±
0.04 days after explosion, has a FWHM of 3.12 ± 0.04 days, a blackbody
temperature of T=17,{500}-9,000+11,500 K, a peak
luminosity of 4.3+/- 0.2× {10}37 {erg} {{{s}}}-1,
and a total integrated energy of 1.27+/- 0.01× {10}43
{erg}. We compare SN 2018oh to several models that may provide
additional heating at early times, including collision with a companion
and a shallow concentration of radioactive nickel. While all of these
models generally reproduce the early K2 light curve shape, we slightly
favor a companion interaction, at a distance of ∼2× {10}12
{cm} based on our early color measurements, although the exact distance
depends on the uncertain viewing angle. Additional confirmation of a
companion interaction in future modeling and observations of SN 2018oh
would provide strong support for a single-degenerate progenitor system.
Title: Solar Magnetic Flux Rope Eruption Simulated by a Data-driven
Magnetohydrodynamic Model
Authors: Guo, Yang; Xia, Chun; Keppens, Rony; Ding, M. D.; Chen, P. F.
Bibcode: 2019ApJ...870L..21G
Altcode: 2018arXiv181210030G
The combination of magnetohydrodynamic (MHD) simulation and
multi-wavelength observations is an effective way to study the
mechanisms of magnetic flux rope eruption. We develop a data-driven MHD
model using the zero-β approximation. The initial condition is provided
by a nonlinear force-free field derived from the magneto-frictional
method based on vector magnetic field observed by the Helioseismic and
Magnetic Imager on board the Solar Dynamics Observatory. The bottom
boundary uses observed time series of the vector magnetic field and the
vector velocity derived by the Differential Affine Velocity Estimator
for Vector Magnetograms. We apply the data-driven model to active
region 11123 observed from 06:00 UT on 2010 November 11 to about 2 hr
later. The evolution of the magnetic field topology coincides with
the flare ribbons observed in the 304 and 1600 Å wavebands by the
Atmospheric Imaging Assembly. The morphology, propagation path, and
propagation range of the flux rope are comparable with the observations
in 304 Å. We also find that a data-constrained boundary condition,
where the bottom boundary is fixed to the initial values, reproduces
a similar simulation result. This model can reproduce the evolution
of a magnetic flux rope in its dynamic eruptive phase.
Title: Recent progress in Asia-Pacific solar physics and astrophysics
Authors: Chen, P. F.; Shibata, K.; Matsumoto, R.
Bibcode: 2018RvMPP...2....5C
Altcode:
More than 40 participants from the solar/astrophysical community
attended the First Asia-Pacific Conference on Plasma Physics. Among
them, four colleagues presented invited talks in the plenary session. In
the Solar/Astron session, there were 23 invited talks and 14 contributed
talks, with another two posters. These talks cover recent progress
obtained in a wide spectrum of topics, including solar and galactic
dynamo, solar and stellar flares, solar and galactic filaments, solar
and astrophysical jets, solar and accretion disk winds, plasma waves and
coronal heating, solar coronal mass ejections, magnetic reconnection in
non-relativistic and relativistic regimes, star and planetary formation,
shock-medium interactions, and even gravitational waves. Laboratory
laser experiments and some new rocket and space missions were also
introduced.
Title: Localizing putative methane sources on Mars from spacecraft
observations and back-trajectory modeling techniques
Authors: Mischna, M.; Fan, S.; Luo, Y.; Yung, Y. L.; Kleinboehl, A.;
Chen, P.; Ehlmann, B. L.
Bibcode: 2018AGUFM.P43K3879M
Altcode:
A variety of measurements of methane in the martian atmosphere have
been made over the past 15 years, showing inconsistencies in methane
abundance, location and lifetime. These observations may be broken
down into two categories, remote and in situ. Remote data consists
of both Earth-based and orbital observations; these have been highly
disparate in time, season and region. In situ data consists solely
of observations made by the Mars Science Laboratory Tunable Laser
Spectrometer. Together, these data have yielded wildly varying
indications of methane in the martian atmosphere. Attempts have
been made to apply numerical models such as general circulation
models (GCMs) to identify source locations and timing of methane
releases, but these remain inconclusive under the current approach
of forward-trajectory plume modeling. Under this approach, passive
'tracers' are introduced into the GCM at specific locations and seasons,
and are allowed to evolve with time, dispersing with the atmospheric
circulation. Relationships are then sought between the evolved methane
plume and observations. Results using this approach are qualitative at
best, and have yet to provide convincing evidence of localized methane
surface sources. In the present work, we shall demonstrate the
alternative approach of back-trajectory plume modeling for source
localization. Back-trajectory modeling uses observations at known
locations and times as the initial condition, and introduces tracers
into the model at that location. By stepping backwards in time, and
using GCM-modeled meteorological conditions as a guide, the trajectory
of these tracers may be mapped back in time. We employ the Caltech
Lagrangian chemistry transport model (CTM) and modeled 3D winds
from the MarsWRF GCM in our study, which also includes atmospheric
photochemistry. GCM simulations are optimized for the times of the
considered methane measurements using data from the Mars Climate
Sounder. At present, the major photochemical pathways in the CTM are
inconsistent with the apparent short lifetime of Mars methane, but new
heterogeneous chemical pathways, including interaction with surface
olivine minerals may be easily included in the model. Results will be
presented demonstrating the technique on the ground-based observations
of Mumma et al., (2009).
Title: ASAS-SN Transient Classification Report for 2018-11-15
Authors: Bose, S.; Holoien, T.; Rich, J.; Dong, S.; Chen, P.; Prieto,
J. L.; Stanek, K. Z.
Bibcode: 2018TNSCR2168....1B
Altcode:
No abstract at ADS
Title: ASAS-SN Transient Classification Report for 2018-11-04
Authors: Bose, S.; Holoien, T. W. S.; Rich, J.; Chen, P.; Dong, S.
Bibcode: 2018TNSCR1694....1B
Altcode:
No abstract at ADS
Title: ASAS-SN Transient Classification Report for 2018-11-29
Authors: Bose, S.; Dong, S.; Chen, P.; Gromadzki, M.; Buckley,
D. A. H.; Prieto, J. L.; Neustadt, J. M.; Stanek, K. Z.; Holoien, T.
Bibcode: 2018TNSCR2047....1B
Altcode:
No abstract at ADS
Title: ASAS-SN Transient Classification Report for 2018-11-14
Authors: Bose, S.; Dong, S.; Chen, P.; Rupert, J.; Stanek, K. Z.;
Stritzinger, M.
Bibcode: 2018TNSCR1770....1B
Altcode:
No abstract at ADS
Title: ASAS-SN Transient Classification Report for 2018-11-15
Authors: Bose, S.; Holoien, T.; Rich, J.; Dong, S.; Chen, P.; Prieto,
J. L.; Stanek, K. Z.
Bibcode: 2018TNSCR2033....1B
Altcode:
No abstract at ADS
Title: ASAS-SN Transient Classification Report for 2018-11-14
Authors: Bose, S.; Dong, S.; Chen, P.; Brink, T. G.; Jaeger, T.;
Filippenko, A. V.; Zheng, W.
Bibcode: 2018TNSCR1771....1B
Altcode:
No abstract at ADS
Title: Spectroscopic Classification of five optical transients
with MDM
Authors: Bose, Subhash; Dong, Subo; Chen, P.; Rupert, J.; Stanek,
K. Z.; Stritzinger, M.
Bibcode: 2018ATel12199....1B
Altcode:
We report optical spectroscopic observation of five optical transients
using OSMOS (range 398-686 nm) mounted on the MDM 2.4m telescope at
KPNO. All targets were discovered by the All-Sky Automated Survey for
Supernovae (ASAS-SN, Shappee et al. 2014) and ATLAS survey (Tonry et
al. 2011 and Tonry et al. ATel #8680).
Title: Spectroscopic Classification of Five Supernova Candidates
with the 2.5-m du Pont Telescope
Authors: Bose, Subhash; Holoien, Tom; Rich, Jeff; Dong, Subo; Chen,
P.; Prieto, Jose L.; Stanek, K. Z.
Bibcode: 2018ATel12212....1B
Altcode:
We report spectroscopic observations and classifications of optical
transients using the du Pont 2.5-m telescope (+ WFCCD) at Las Campanas
Observatory. Targets were discovered by the All-Sky Automated Survey for
Supernovae (ASAS-SN, Shappee et al. 2014) (ATel #12170, ATel #12147,
ATel #12194), ATLAS survey (Tonry et al. 2011 and Tonry et al. ATel
#8680) and the Zwicky Transient Facility (ZTF; ATel #11266).
Title: ASAS-SN Transient Classification Report for 2018-11-14
Authors: Bose, S.; Chen, P.; Dong, S.
Bibcode: 2018TNSCR1769....1B
Altcode:
No abstract at ADS
Title: ASAS-SN Transient Classification Report for 2018-11-14
Authors: Bose, S.; Chen, P.; Dong, S.
Bibcode: 2018TNSCR2167....1B
Altcode:
No abstract at ADS
Title: Observations of Turbulent Magnetic Reconnection within a
Solar Current Sheet
Authors: Cheng, X.; Li, Y.; Wan, L. F.; Ding, M. D.; Chen, P. F.;
Zhang, J.; Liu, J. J.
Bibcode: 2018ApJ...866...64C
Altcode: 2018arXiv180806071C
Magnetic reconnection is a fundamental physical process in various
astrophysical, space, and laboratory environments. Many pieces of
evidence for magnetic reconnection have been uncovered. However, its
specific processes that could be fragmented and turbulent have been
short of direct observational evidence. Here, we present observations
of a super-hot current sheet during the SOL2017-09-10T X8.2-class solar
flare that display the fragmented and turbulent nature of magnetic
reconnection. As bilateral plasmas converge toward the current sheet,
significant plasma heating and nonthermal motions are detected
therein. Two oppositely directed outflow jets are intermittently
expelled out of the fragmenting current sheet, whose intensity shows a
power-law distribution in the spatial frequency domain. The intensity
and velocity of the sunward outflow jets also display a power-law
distribution in the temporal frequency domain. The length-to-width
ratio of current sheet is estimated to be larger than the theoretical
threshold and thus ensures its occurrence. The observations therefore
suggest that fragmented and turbulent magnetic reconnection occurs in
the long stretching current sheet.
Title: Observation of an Unusual Upward-Going Cosmic-Ray-like Event
in the Third Flight of ANITA
Authors: Gorham, P. W.; Rotter, B.; Allison, P.; Banerjee, O.; Batten,
L.; Beatty, J. J.; Bechtol, K.; Belov, K.; Besson, D. Z.; Binns,
W. R.; Bugaev, V.; Cao, P.; Chen, C. C.; Chen, C. H.; Chen, P.;
Clem, J. M.; Connolly, A.; Cremonesi, L.; Dailey, B.; Deaconu, C.;
Dowkontt, P. F.; Fox, B. D.; Gordon, J. W. H.; Hast, C.; Hill, B.;
Hughes, K.; Huang, J. J.; Hupe, R.; Israel, M. H.; Javaid, A.; Lam,
J.; Liewer, K. M.; Lin, S. Y.; Liu, T. C.; Ludwig, A.; Macchiarulo,
L.; Matsuno, S.; Miki, C.; Mulrey, K.; Nam, J.; Naudet, C. J.; Nichol,
R. J.; Novikov, A.; Oberla, E.; Olmedo, M.; Prechelt, R.; Prohira,
S.; Rauch, B. F.; Roberts, J. M.; Romero-Wolf, A.; Russell, J. W.;
Saltzberg, D.; Seckel, D.; Schoorlemmer, H.; Shiao, J.; Stafford,
S.; Stockham, J.; Stockham, M.; Strutt, B.; Varner, G. S.; Vieregg,
A. G.; Wang, S. H.; Wissel, S. A.
Bibcode: 2018PhRvL.121p1102G
Altcode: 2018arXiv180305088G
We report on an upward traveling, radio-detected cosmic-ray-like
impulsive event with characteristics closely matching an extensive
air shower. This event, observed in the third flight of the Antarctic
Impulsive Transient Antenna (ANITA), a NASA-sponsored long-duration
balloon payload, is consistent with a similar event reported in a
previous flight. These events could be produced by the atmospheric
decay of an upward-propagating τ lepton produced by a ντ
interaction, although their relatively steep arrival angles create
tension with the standard model neutrino cross section. Each of the two
events have a posteriori background estimates of ≲10-2
events. If these are generated by τ -lepton decay, then either the
charged-current ντ cross section is suppressed at EeV
energies, or the events arise at moments when the peak flux of a
transient neutrino source was much larger than the typical expected
cosmogenic background neutrinos.
Title: Waiting time distributions of solar and stellar flares:
Poisson process or with memory?
Authors: Li, C.; Zhong, S. J.; Xu, Z. G.; He, H.; Yan, Y.; Chen,
P. F.; Fang, C.
Bibcode: 2018MNRAS.479L.139L
Altcode: 2018MNRAS.tmpL.121L
We present the waiting time statistics of solar flares observed during
the solar cycle 23 and of stellar flares produced by a solar-type star
(KIC 11551430). The Kolmogorov-Smirnov test is applied to examine the
reliability of Poisson hypothesis for the flare production. Different
degrees of departure from a Poisson process have been found, depending
on the flare intensities and levels of star activities. We then
fit the waiting time distributions with both the non-stationary
Poisson function and the Weibull function. It is evident that a
certain amount of memory is present during the period of high solar
activities, consistent with the result of Telloni et al. Furthermore,
our analysis indicates that the occurrence of relatively `weak' flares
are persistently correlated, while the production of `super flares'
is closer to a stochastic process statistically.
Title: Upward-Pointing Cosmic-Ray-like Events Observed with ANITA
Authors: Romero-Wolf, Andres; Gorham, P. W.; Nam, J.; Hoover, S.;
Allison, P.; Banerjee, O.; Batten, L.; Beatty, J. J.; Belov, K.;
Besson, D. Z.; Binns, W. R.; Bugaev, V.; Cao, P.; Chen, C.; Chen,
P.; Clem, J. M.; Connolly, A.; Dailey, B.; Deaconu, C.; Cremonesi,
L.; Dowkontt, P. F.; DuVernois, M. A.; Field, R. C.; Fox, B. D.;
Goldstein, D.; Gordon, J.; Hast, C.; Hebert, C. L.; Hill, B.; Hughes,
K.; Hupe, R.; Israel, M. H.; Javaid, A.; Kowalski, J.; Lam, J.; Ludwig,
A.; Learned, J. G.; Liewer, K. M.; Liu, T. C.; Link, J. T.; Lusczek,
E.; Matsuno, S.; Mercurio, B. C.; Miki, C.; Miocinovic, P.; Mottram,
M.; Mulrey, K.; Naudet, C. J.; Ng, J.; Nichol, R. J.; Novikov, A.;
Palladino, K.; Prohira, S.; Rauch, B. F.; Reil, K.; Roberts, J.;
Rosen, M.; Rotter, B.; Russell, J.; Ruckman, L.; Saltzberg, D.;
Seckel, D.; Stafford, S.; Stockham, J.; Stockham, M.; Strutt, B.;
Tatem, K.; Varner, G. S.; Vieregg, A. G.; Walz, D.; Wissel, S. A.; Wu,
F.; Alvarez-Muñiz, J.; Carvalho, W., Jr.; Schoorlemmer, H.; Zas, E.
Bibcode: 2018arXiv181000439R
Altcode:
These proceedings address a recent publication by the ANITA
collaboration of four upward- pointing cosmic-ray-like events observed
in the first flight of ANITA. Three of these events were consistent
with stratospheric cosmic-ray air showers where the axis of propagation
does not inter- sect the surface of the Earth. The fourth event was
consistent with a primary particle that emerges from the surface of
the ice suggesting a possible {\tau}-lepton decay as the origin of
this event. These proceedings follow-up on the modeling and testing
of the hypothesis that this event was of {\tau} neutrino origin.
Title: ASAS-SN Transient Classification Report for 2018-09-05
Authors: Bose, S.; Duan, X.; Chen, P.; Dong, S.; Rupert, J.; Stanek,
K. Z.; Prieto, J. L.
Bibcode: 2018TNSCR1307....1B
Altcode:
No abstract at ADS
Title: Observations of Two Successive EUV Waves and Their Mode
Conversion
Authors: Chandra, Ramesh; Chen, P. F.; Joshi, Reetika; Joshi, Bhuwan;
Schmieder, Brigitte
Bibcode: 2018ApJ...863..101C
Altcode: 2018arXiv180611350C
In this paper, we present the observations of two successive fast-mode
extreme ultraviolet (EUV) wave events observed on 2016 July 23. Both
fast-mode waves were observed by the Atmospheric Imaging Assembly
instrument on board the Solar Dynamics Observatory satellite, with a
traveling speed of ≈675 and 640 km s-1, respectively. These
two wave events were associated with two filament eruptions and two
GOES M-class solar flares from the NOAA active region 12565, which was
located near the western limb. The EUV waves mainly move toward the
south direction. We observed the interaction of the EUV waves with a
helmet streamer further away to the south. When either or one of the
EUV waves penetrates into the helmet streamer, a slowly propagating wave
with a traveling speed of ≈150 km s-1 is observed along the
streamer. We suggest that the slowly moving waves are slow-mode waves,
and interpret this phenomenon as the magnetohydrodynamic wave-mode
conversion from the fast mode to the slow mode. Furthermore, we observed
several stationary fronts to the north and south of the source region.
Title: Antarctic surface reflectivity calculations and measurements
from the ANITA-4 and HiCal-2 experiments
Authors: Prohira, S.; Novikov, A.; Dasgupta, P.; Jain, P.; Nande,
S.; Allison, P.; Banerjee, O.; Batten, L.; Beatty, J. J.; Belov, K.;
Besson, D. Z.; Binns, W. R.; Bugaev, V.; Cao, P.; Chen, C.; Chen,
P.; Clem, J. M.; Connolly, A.; Cremonesi, L.; Dailey, B.; Deaconu,
C.; Dowkontt, P. F.; Fox, B. D.; Gordon, J.; Gorham, P. W.; Hast, C.;
Hill, B.; Hupe, R.; Israel, M. H.; Lam, J.; Liu, T. C.; Ludwig, A.;
Matsuno, S.; Miki, C.; Mottram, M.; Mulrey, K.; Nam, J.; Nichol, R. J.;
Oberla, E.; Ratzlaff, K.; Rauch, B. F.; Romero-Wolf, A.; Rotter, B.;
Russell, J.; Saltzberg, D.; Seckel, D.; Schoorlemmer, H.; Stafford,
S.; Stockham, J.; Stockham, M.; Strutt, B.; Tatem, K.; Varner, G. S.;
Vieregg, A. G.; Wissel, S. A.; Wu, F.; Young, R.; Anita Collaboration
Bibcode: 2018PhRvD..98d2004P
Altcode: 2018arXiv180108909P
The balloon-borne HiCal radio-frequency (RF) transmitter, in
concert with the ANITA radio-frequency receiver array, is designed
to measure the Antarctic surface reflectivity in the RF wavelength
regime. The amplitude of surface-reflected transmissions from HiCal,
registered as triggered events by ANITA, can be compared with the
direct transmissions preceding them by O (10 ) microseconds, to
infer the surface power reflection coefficient R . The first HiCal
mission (HiCal-1, Jan. 2015) yielded a sample of 100 such pairs,
resulting in estimates of R at highly glancing angles (i.e., zenith
angles approaching 90°), with measured reflectivity for those events
which exceeded extant calculations [P. W. Gorham et al., Journal of
Astronomical Instrumentation, 1740002 (2017)]. The HiCal-2 experiment,
flying from December 2016-January 2017, provided an improvement by
nearly 2 orders of magnitude in our event statistics, allowing a
considerably more precise mapping of the reflectivity over a wider
range of incidence angles. We find general agreement between the
HiCal-2 reflectivity results and those obtained with the earlier
HiCal-1 mission, as well as estimates from Solar reflections in
the radio-frequency regime [D. Z. Besson et al., Radio Sci. 50, 1
(2015)]. In parallel, our calculations of expected reflectivity
have matured; herein, we use a plane-wave expansion to estimate
the reflectivity R from both a flat, smooth surface (and, in so
doing, recover the Fresnel reflectivity equations) and also a curved
surface. Multiplying our flat-smooth reflectivity by improved Earth
curvature and surface roughness corrections now provides significantly
better agreement between theory and the HiCal-2 measurements.
Title: Project of a New 2.5m Solar Telescope
Authors: Fang, Cheng; Chen, P. F.; Li, Zhen; Cao, Wenda; Hao, Qi;
Ding, Mingde; Gu, Baizhong; Yuan, Xiangyan
Bibcode: 2018cosp...42E1041F
Altcode:
A project of a 2.5m Solar Telescope has been worked out in China. It
is the first facility in the world with a special innovation design
and can conduct both high-resolution solar observations and the
large-field of view (FOV) night survey. Its scientific objectives
cover solar physics and time-domain astronomy, all of which are recent
hot topics in astronomy. As a large on-axis solar telescope in the
world with a larger FOV (7') than all the large solar telescopes
operating at present, it can provide unprecedented high-resolution
solar imaging and magnetic field data, which can help us obtain
breakthrough achievements on the study of solar active regions and
solar eruptions. The data are also very useful for the study of space
weather. As a large telescope in China, the telescope is very unique
in continuously monitoring short-time transient events by filling
the gap in the specific time-zone. Moreover, the telescope can make
essential contribution to training the graduate and undergraduate
students majoring in observational astronomy.
Title: Constraints on the diffuse high-energy neutrino flux from
the third flight of ANITA
Authors: Gorham, P. W.; Allison, P.; Banerjee, O.; Batten, L.; Beatty,
J. J.; Bechtol, K.; Belov, K.; Besson, D. Z.; Binns, W. R.; Bugaev, V.;
Cao, P.; Chen, C. C.; Chen, C. H.; Chen, P.; Clem, J. M.; Connolly,
A.; Cremonesi, L.; Dailey, B.; Deaconu, C.; Dowkontt, P. F.; Fox,
B. D.; Gordon, J. W. H.; Hast, C.; Hill, B.; Hsu, S. Y.; Huang, J. J.;
Hughes, K.; Hupe, R.; Israel, M. H.; Liewer, K. M.; Liu, T. C.; Ludwig,
A. B.; Macchiarulo, L.; Matsuno, S.; Miki, C.; Mulrey, K.; Nam, J.;
Naudet, C.; Nichol, R. J.; Novikov, A.; Oberla, E.; Prohira, S.; Rauch,
B. F.; Roberts, J. M.; Romero-Wolf, A.; Rotter, B.; Russell, J. W.;
Saltzberg, D.; Seckel, D.; Schoorlemmer, H.; Shiao, J.; Stafford, S.;
Stockham, J.; Stockham, M.; Strutt, B.; Sutherland, M. S.; Varner,
G. S.; Vieregg, A. G.; Wang, S. H.; Wissel, S. A.; Anita Collaboration
Bibcode: 2018PhRvD..98b2001G
Altcode: 2018arXiv180302719G; 2018arXiv180302719A
The Antarctic Impulsive Transient Antenna, a NASA long-duration
balloon payload, searches for radio emission from interactions of
ultrahigh-energy neutrinos in polar ice. The third flight of the
Antarctic Impulsive Transient Antenna was launched in December 2014
and completed a 22-day flight. We present the results of three analyses
searching for Askaryan radio emission of neutrino origin. In the most
sensitive of the analyses, we find one event in the signal region on
an expected background of 0. 7-0.3+0.5. Though
consistent with the background estimate, the event remains compatible
with a neutrino hypothesis even after additional postunblinding
scrutiny.
Title: Observation of Reconstructable Radio Emission Coincident with
an X-Class Solar Flare in the Askaryan Radio Array Prototype Station
Authors: Allison, P.; Archambault, S.; Auffenberg, J.; Bard, R.;
Beatty, J. J.; Beheler-Amass, M.; Besson, D. Z.; Beydler, M.; Bora,
C.; Chen, C. -C.; Chen, C. -H.; Chen, P.; Clark, B. A.; Clough, A.;
Connolly, A.; Davies, J.; Deaconu, C.; DuVernois, M. A.; Friedman,
E.; Fox, B.; Gorham, P. W.; Hanson, J.; Hanson, K.; Haugen, J.; Hill,
B.; Hoffman, K. D.; Hong, E.; Hsu, S. -Y.; Hu, L.; Huang, J. -J.;
Huang, M. -H.; Ishihara, A.; Karle, A.; Kelley, J. L.; Khandelwal, R.;
Kim, M.; Kravchenko, I.; Kruse, J.; Kurusu, K.; Landsman, H.; Latif,
U. A.; Laundrie, A.; Li, C. -J.; Liu, T. C.; Lu, M. -Y.; Mase, K.;
Maunu, R.; Meures, T.; Miki, C.; Nam, J.; Nichol, R. J.; Nir, G.;
Oberla, E.; ÓMurchadha, A.; Pan, Y.; Pfendner, C.; Ratzlaff, K.;
Richman, M.; Roth, J.; Rotter, B.; Sandstrom, P.; Seckel, D.; Shiao,
Y. -S.; Shultz, A.; Song, M.; Stockham, J.; Stockham, M.; Sullivan,
M.; Touart, J.; Tu, H. -Y.; Varner, G. S.; Vieregg, A. G.; Wang,
M. -Z.; Wang, S. -H.; Wissel, S. A.; Yoshida, S.; Young, R.
Bibcode: 2018arXiv180703335A
Altcode:
The Askaryan Radio Array (ARA) reports an observation of radio
emission coincident with the "Valentine's Day" solar flare on
Feb. 15$^{\rm{th}}$, 2011 in the prototype "Testbed" station. We find
$\sim2000$ events that passed our neutrino search criteria during the 70
minute period of the flare, all of which reconstruct to the location of
the sun. A signal analysis of the events reveals them to be consistent
with that of bright thermal noise correlated across antennas. This is
the first natural source of radio emission reported by ARA that is
tightly reconstructable on an event-by-event basis. The observation
is also the first for ARA to point radio from individual events to an
extraterrestrial source on the sky. We comment on how the solar flares,
coupled with improved systematic uncertainties in reconstruction
algorithms, could aid in a mapping of any above-ice radio emission,
such as that from cosmic-ray air showers, to astronomical locations
on the sky.
Title: Spectroscopic Classification of two ASAS-SN Supernovae with MDM
Authors: Bose, Subhash; Dong, Subo; Chen, P.; Prieto, Jose L.; Rupert,
J.; Stanek, K. Z.
Bibcode: 2018ATel11837....1B
Altcode:
We report optical spectroscopic observation of supernova candidates
ASASSN-18ll/2018cdh (ATel #11686) and ASASSN-18od/2018dda (ATel #11832)
using OSMOS (range 398-686 nm) mounted on the MDM 2.4m telescope
at KPNO.
Title: ASAS-SN Transient Discovery Report for 2018-07-16
Authors: Nicholls, B.; Chen, P.; Dong, S.; Stanek, K. Z.
Bibcode: 2018TNSTR.989....1N
Altcode:
No abstract at ADS
Title: Project of a New 2.5m Solar Telescope
Authors: Fang, Cheng; Chen, P. F.; Li, Zhen; Cao, Wenda; Hao, Qi;
Ding, Mingde; Gu, Baizhong; Yuan, Xiangyan
Bibcode: 2018cosp...42E1042F
Altcode:
A project of a 2.5m Solar Telescope has been worked out in China. It
is the first facility in the world with a special innovation design
and can conduct both high-resolution solar observations and the
large-field of view (FOV) night survey. Its scientific objectives
cover solar physics and time-domain astronomy, all of which are recent
hot topics in astronomy. As a large on-axis solar telescope in the
world with a larger FOV (7') than all the large solar telescopes
operating at present, it can provide unprecedented high-resolution
solar imaging and magnetic field data, which can help us obtain
breakthrough achievements on the study of solar active regions and
solar eruptions. The data are also very useful for the study of space
weather. As a large telescope in China, the telescope is very unique
in continuously monitoring short-time transient events by filling
the gap in the specific time-zone. Moreover, the telescope can make
essential contribution to training the graduate and undergraduate
students majoring in observational astronomy.
Title: ASAS-SN Transient Discovery Report for 2018-06-08
Authors: Chen, P.; Stanek, K. Z.
Bibcode: 2018TNSTR.778....1C
Altcode:
No abstract at ADS
Title: Dynamic tunable notch filters for the Antarctic Impulsive
Transient Antenna (ANITA)
Authors: Allison, P.; Banerjee, O.; Beatty, J. J.; Connolly, A.;
Deaconu, C.; Gordon, J.; Gorham, P. W.; Kovacevich, M.; Miki, C.;
Oberla, E.; Roberts, J.; Rotter, B.; Stafford, S.; Tatem, K.; Batten,
L.; Belov, K.; Besson, D. Z.; Binns, W. R.; Bugaev, V.; Cao, P.;
Chen, C.; Chen, P.; Chen, Y.; Clem, J. M.; Cremonesi, L.; Dailey,
B.; Dowkontt, P. F.; Hsu, S.; Huang, J.; Hupe, R.; Israel, M. H.;
Kowalski, J.; Lam, J.; Learned, J. G.; Liewer, K. M.; Liu, T. C.;
Ludwig, A. B.; Matsuno, S.; Mulrey, K.; Nam, J.; Nichol, R. J.;
Novikov, A.; Prohira, S.; Rauch, B. F.; Ripa, J.; Romero-Wolf, A.;
Russell, J.; Saltzberg, D.; Seckel, D.; Shiao, J.; Stockham, J.;
Stockham, M.; Strutt, B.; Varner, G. S.; Vieregg, A. G.; Wang, S.;
Wissel, S. A.; Wu, F.; Young, R.
Bibcode: 2018NIMPA.894...47A
Altcode: 2017arXiv170904536A
The Antarctic Impulsive Transient Antenna (ANITA) is a NASA
long-duration balloon experiment with the primary goal of detecting
ultra-high-energy (> 1018eV) neutrinos via the Askaryan
Effect. The fourth ANITA mission, ANITA-IV, recently flew from Dec
2 to Dec 29, 2016. For the first time, the Tunable Universal Filter
Frontend (TUFF) boards were deployed for mitigation of narrow-band,
anthropogenic noise with tunable, switchable notch filters. The TUFF
boards also performed second-stage amplification by approximately 45 dB
to boost the ∼ μV-level radio frequency (RF) signals to ∼ mV-level
for digitization, and supplied power via bias tees to the first-stage,
antenna-mounted amplifiers. The other major change in signal processing
in ANITA-IV is the resurrection of the 90 ° hybrids deployed previously
in ANITA-I, in the trigger system, although in this paper we focus on
the TUFF boards. During the ANITA-IV mission, the TUFF boards were
successfully operated throughout the flight. They contributed to a
factor of 2.8 higher total instrument livetime on average in ANITA-IV
compared to ANITA-III due to reduction of narrow-band, anthropogenic
noise before a trigger decision is made.
Title: ASAS-SN Transient Discovery Report for 2018-06-22
Authors: Chen, P.; Stanek, K. Z.; Dong, S.
Bibcode: 2018TNSTR.869....1C
Altcode:
No abstract at ADS
Title: ASAS-SN Transient Classification Report for 2018-06-26
Authors: Bose, S.; Dong, S.; Chen, P.; Stanek, K. Z.; Shields, J.
Bibcode: 2018TNSCR.891....1B
Altcode:
No abstract at ADS
Title: ASAS-SN Transient Classification Report for 2018-06-20
Authors: Bose, S.; Dong, S.; Chen, P.; Stanek, K. Z.; Shields, J.
Bibcode: 2018TNSCR2105....1B
Altcode:
No abstract at ADS
Title: ASAS-SN Transient Classification Report for 2018-06-20
Authors: Bose, S.; Dong, S.; Chen, P.; Stanek, K. Z.; Shields, J.
Bibcode: 2018TNSCR.861....1B
Altcode:
No abstract at ADS
Title: VizieR Online Data Catalog: ASASSN-15oi UBVI M2W1W2 light
curves (Holoien+, 2016)
Authors: Holoien, T. W. -S.; Kochanek, C. S.; Prieto, J. L.; Grupe,
D.; Chen, P.; Godoy-Rivera, D.; Stanek, K. Z.; Shappee, B. J.; Dong,
S.; Brown, J. S.; Basu, U.; Beacom, J. F.; Bersier, D.; Brimacombe,
J.; Carlson, E. K.; Falco, E.; Johnston, E.; Madore, B. F.; Pojmanski,
G.; Seibert, M.
Bibcode: 2018yCat..74633813H
Altcode:
After the transient was classified as a TDE, we obtained a series of 26
Swift XRT and UVOT target-of-opportunity (ToO) observations. The UVOT
observations were obtained in six filters: V (5468Å), B (4392Å),
U (3465Å), UVW1 (2600Å), UVM2 (2246Å), and UVW2 (1928Å) We
also obtained BVI images with the Las Cumbres Observatory Global
Telescope Network (LCOGT; Brown et al. 2013) 1-m telescopes at Siding
Spring, South African Astronomical, and Cerro Tololo Inter-America
Observatories. (1 data file).
Title: ASAS-SN Transient Classification Report for 2018-05-14
Authors: Bose, S.; Holoien, T.; Prieto, J. L.; Dong, S.; Chen, P.;
Stanek, K. Z.
Bibcode: 2018TNSCR.640....1B
Altcode:
No abstract at ADS
Title: Spectroscopic Classification of SNe ASASSN-18hq and 2018ass
with the 2.5-m du Pont Telescope
Authors: Bose, Subhash; Holoien, Tom; Prieto, Jose L.; Dong, Subo;
Chen, P.; Stanek, K. Z.
Bibcode: 2018ATel11643....1B
Altcode:
We report spectroscopic observations of ASASSN-18hq/2018arx (ATel
#11541) and SN 2018ass obtained on UT2018-04-19.3 using the du Pont
2.5-m telescope (+ WFCCD) at Las Campanas Observatory.
Title: ASAS-SN Transient Classification Report for 2018-04-13
Authors: Bose, S.; Dong, S.; Chen, P.; Rupert, J.; Shields, J.;
Stanek, K. Z.; Prieto, J. L.
Bibcode: 2018TNSCR.489....1B
Altcode:
No abstract at ADS
Title: ASAS-SN Transient Classification Report for 2018-04-06
Authors: Prieto, J. L.; Rupert, J.; Dong, S.; Chen, P.; Shields, J.;
Stanek, K. Z.
Bibcode: 2018TNSCR.449....1P
Altcode:
No abstract at ADS
Title: ASAS-SN Transient Discovery Report for 2018-04-04
Authors: Chen, P.; Dong, S.; Stanek, K.
Bibcode: 2018TNSTR.440....1C
Altcode:
No abstract at ADS
Title: The highly luminous Type Ibn supernova ASASSN-14ms
Authors: Vallely, P. J.; Prieto, J. L.; Stanek, K. Z.; Kochanek, C. S.;
Sukhbold, T.; Bersier, D.; Brown, J. S.; Chen, P.; Dong, S.; Falco,
E.; Berlind, P.; Calkins, M.; Koff, R. A.; Kiyota, S.; Brimacombe, J.;
Shappee, B. J.; Holoien, T. W. -S.; Thompson, T. A.; Stritzinger, M. D.
Bibcode: 2018MNRAS.475.2344V
Altcode: 2017arXiv171100862V
We present photometric and spectroscopic follow-up observations of the
highly luminous Type Ibn supernova ASASSN-14ms, which was discovered
on UT 2014-12-26.61 at mV ∼ 16.5. With a peak absolute
V-band magnitude brighter than -20.5, a peak bolometric luminosity of
1.7 × 1044 erg s-1, and a total radiated energy
of 2.1 × 1050 erg, ASASSN-14ms is one of the most luminous
Type Ibn supernovae yet discovered. In simple models, the most likely
power source for this event is a combination of the radioactive decay
of 56Ni and 56Co at late times and the interaction
of supernova ejecta with the progenitor's circumstellar medium at early
times, although we cannot rule out the possibility of a magnetar-powered
light curve. The presence of a dense circumstellar medium is indicated
by the intermediate-width He I features in the spectra. The faint
(mg ∼ 21.6) host galaxy SDSS J130408.52+521846.4 has
an oxygen abundance below 12 + log (O/H) ≲ 8.3, a stellar mass of
M* ∼ 2.6 × 108 M⊙, and a star
formation rate of SFR ∼ 0.02 M⊙ yr-1.
Title: Spectroscopic Classification of Three ASAS-SN Supernovae
Authors: Bose, Subhash; Dong, Subo; Chen, P.; Rupert, J.; Shields,
J.; Stanek, K. Z.; Prieto, Jose L.
Bibcode: 2018ATel11530....1B
Altcode:
We report optical spectroscopic observation of supernova candidates
ASASSN-18gs/2018apn, ASASSN-18gu/2018aqa and ASASSN-18gz/2018aqe
(ATel #11521) using OSMOS (range 398-686 nm) mounted on the MDM 2.4m
telescope at KPNO.
Title: Spectroscopic Classification of Nine Optical Transients with
the 2.5-m du Pont Telescope
Authors: Bose, Subhash; Holoien, Tom; Prieto, Jose L.; Dong, Subo;
Chen, P.; Stanek, K. Z.
Bibcode: 2018ATel11551....1B
Altcode:
We report spectroscopic observations and classifications of
optical transients using the du Pont 2.5-m telescope (+ WFCCD)
at Las Campanas Observatory. Targets were discovered by the
All-Sky Automated Survey for Supernovae (ASAS-SN, Shappee et
al. 2014) (ATel #11391, ATel #11343, ATel #11459), Gaia Alerts
(http://gsaweb.ast.cam.ac.uk/alerts/alertsindex) and A. Rest et
al. (for 2018agk).
Title: ASAS-SN Transient Classification Report for 2018-04-18
Authors: Bose, S.; Holoien, T.; Dong, S.; Chen, P.; Stanek, K. Z.;
Prieto, J. L.
Bibcode: 2018TNSCR.510....1B
Altcode:
No abstract at ADS
Title: ASAS-SN Transient Classification Report for 2018-04-18
Authors: Bose, S.; Prieto, J. L.; Dong, S.; Chen, P.; Rupert, J.;
Shields, J.; Stanek, K. Z.
Bibcode: 2018TNSCR.509....1B
Altcode:
No abstract at ADS
Title: ASAS-SN Transient Classification Report for 2018-04-12
Authors: Bose, S.; Dong, S.; Chen, P.; Rupert, J.; Shields, J.;
Stanek, K. Z.; Prieto, J. L.
Bibcode: 2018TNSCR.484....1B
Altcode:
No abstract at ADS
Title: Three-dimensional MHD Simulations of Solar Prominence
Oscillations in a Magnetic Flux Rope
Authors: Zhou, Yu-Hao; Xia, C.; Keppens, R.; Fang, C.; Chen, P. F.
Bibcode: 2018ApJ...856..179Z
Altcode: 2018arXiv180303385Z
Solar prominences are subject to all kinds of perturbations during
their lifetime, and frequently demonstrate oscillations. The
study of prominence oscillations provides an alternative way to
investigate their internal magnetic and thermal structures because
the characteristics of the oscillations depend on their interplay
with the solar corona. Prominence oscillations can be classified into
longitudinal and transverse types. We perform three-dimensional ideal
magnetohydrodynamic simulations of prominence oscillations along a
magnetic flux rope, with the aim of comparing the oscillation periods
with those predicted by various simplified models and examining the
restoring force. We find that the longitudinal oscillation has a period
of about 49 minutes, which is in accordance with the pendulum model
where the field-aligned component of gravity serves as the restoring
force. In contrast, the horizontal transverse oscillation has a period
of about 10 minutes and the vertical transverse oscillation has a
period of about 14 minutes, and both of them can be nicely fitted
with a two-dimensional slab model. We also find that the magnetic
tension force dominates most of the time in transverse oscillations,
except for the first minute when magnetic pressure overwhelms it.
Title: Transient Classification Report for 2018-03-18
Authors: Tucker, M. A.; Shappee, B. J.; Dong, S.; Bose, S.; Chen, P.
Bibcode: 2018TNSCR.363....1T
Altcode:
No abstract at ADS
Title: A global weighted mean temperature model based on empirical
orthogonal function analysis
Authors: Li, Qinzheng; Chen, Peng; Sun, Langlang; Ma, Xiaping
Bibcode: 2018AdSpR..61.1398L
Altcode:
A global empirical orthogonal function (EOF) model of the tropospheric
weighted mean temperature called GEOFM_Tm was developed using
high-precision Global Geodetic Observing System (GGOS) Atmosphere
Tm data during the years 2008-2014. Due to the quick
convergence of EOF decomposition, it is possible to use the first
four EOF series, which consists base functions Uk and
associated coefficients Pk, to represent 99.99% of the
overall variance of the original data sets and its spatial-temporal
variations. Results show that U1 displays a prominent
latitude distribution profile with positive peaks located at low
latitude region. U2 manifests an asymmetric pattern that
positive values occurred over 30° in the Northern Hemisphere, and
negative values were observed at other regions. U3 and
U4 displayed significant anomalies in Tibet and North
America, respectively. Annual variation is the major component
of the first and second associated coefficients P1 and
P2, whereas P3 and P4 mainly reflects
both annual and semi-annual variation components. Furthermore, the
performance of constructed GEOFM_Tm was validated by comparison with
GTm_III and GTm_N with different kinds of data including GGOS Atmosphere
Tm data in 2015 and radiosonde data from Integrated Global
Radiosonde Archive (IGRA) in 2014. Generally speaking, GEOFM_Tm can
achieve the same accuracy and reliability as GTm_III and GTm_N models
in a global scale, even has improved in the Antarctic and Greenland
regions. The MAE and RMS of GEOFM_Tm tend to be 2.49 K and 3.14 K with
respect to GGOS Tm data, respectively; and 3.38 K and 4.23
K with respect to IGRA sounding data, respectively. In addition, those
three models have higher precision at low latitude than middle and high
latitude regions. The magnitude of Tm remains at the range
of 220-300 K, presented a high correlation with geographic latitude. In
the Northern Hemisphere, there was a significant enhancement at high
latitude region reaching 270 K during summer. GEOFM_Tm is capable to
represent the spatiotemporal variations of Tm, with the
high accuracy and reliability in a global scale, therefore, will be
of great significance to the real-time GNSS water vapor inversion and
climate studies.
Title: ASAS-SN Transient Classification Report for 2018-03-05
Authors: Prieto, J. L.; Rupert, J.; Dong, S.; Chen, P.; Shields, J.;
Stanek, K. Z.
Bibcode: 2018TNSCR.301....1P
Altcode:
No abstract at ADS
Title: ASAS-SN Transient Classification Report for 2018-03-06
Authors: Prieto, J. L.; Rupert, J.; Dong, S.; Chen, P.; Shields, J.;
Stanek, K. Z.
Bibcode: 2018TNSCR.306....1P
Altcode:
No abstract at ADS
Title: ASAS-SN Transient Discovery Report for 2018-03-05
Authors: Chen, P.; Dong, S.; Stanek, K.
Bibcode: 2018TNSTR.298....1C
Altcode:
No abstract at ADS
Title: ASASSN-18fb: Discovery of a Bright Candidate Microlensing
Event Located Away from the Galactic Bulge
Authors: Stanek, K. Z.; Dong, Subo; Chen, P.; Prieto, J. L.; Kochanek,
C. S.; Shields, J. V.; Thompson, T. A.; Shappee, B. J.; Holoien,
T. W. -S.; Stritzinger, M.
Bibcode: 2018ATel11389....1S
Altcode:
During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN,
Shappee et al. 2014), using data from the quadruple 14-cm "Cassius"
telescope in CTIO, Chile, we detect a new transient source, most likely
a bright microlensing event, located near the Galactic plane, but more
than 60 degrees away from the Galactic center Object RA (J2000) DEC
(J2000) Gal l (deg) Gal b (deg) Disc.
Title: ASAS-SN Transient Classification Report for 2018-03-18
Authors: Tucker, M. A.; Shappee, B. J.; Dong, S.; Bose, S.; Chen, P.
Bibcode: 2018TNSCR.364....1T
Altcode:
No abstract at ADS
Title: Automated Detection Methods for Solar Activities and an
Application for Statistic Analysis of Solar Filament
Authors: Hao, Q.; Chen, P. F.; Fang, C.
Bibcode: 2018IAUS..340..101H
Altcode: 2018arXiv180403320H
With the rapid development of telescopes, both temporal cadence and
the spatial resolution of observations are increasing. This in turn
generates vast amount of data, which can be efficiently searched only
with automated detections in order to derive the features of interest
in the observations. A number of automated detection methods and
algorithms have been developed for solar activities, based on the image
processing and machine learning techniques. In this paper, after briefly
reviewing some automated detection methods, we describe our efficient
and versatile automated detection method for solar filaments. It is
able not only to recognize filaments, determine the features such as
the position, area, spine, and other relevant parameters, but also to
trace the daily evolution of the filaments. It is applied to process
the full disk Hα data observed in nearly three solar cycles, and some
statistic results are presented.
Title: UFFO/ Lomonosov: The Payload for the Observation of Early
Photons from Gamma Ray Bursts
Authors: Park, I. H.; Panasyuk, M. I.; Reglero, V.; Chen,
P.; Castro-Tirado, A. J.; Jeong, S.; Bogomolov, V.; Brandt, S.;
Budtz-Jørgensen, C.; Chang, S. -H.; Chang, Y. Y.; Chen, C. -R.; Chen,
C. -W.; Choi, H. S.; Connell, P.; Eyles, C.; Gaikov, G.; Garipov,
G.; Huang, J. -J.; Huang, M. -H. A.; Jeong, H. M.; Kim, J. E.; Kim,
M. B.; Kim, S. -W.; Lee, H. K.; Lee, J.; Lim, H.; Lin, C. -Y.; Liu,
T. -C.; Nam, J. W.; Petrov, V.; Ripa, J.; Rodrigo, J. M.; Svertilov,
S.; Wang, M. -Z.; Yashin, I.
Bibcode: 2018SSRv..214...14P
Altcode:
The payload of the UFFO (Ultra-Fast Flash Observatory)-pathfinder
now onboard the Lomonosov spacecraft (hereafter UFFO/ Lomonosov)
is a dedicated instrument for the observation of GRBs. Its primary
aim is to capture the rise phase of the optical light curve, one of
the least known aspects of GRBs. Fast response measurements of the
optical emission of GRB will be made by a Slewing Mirror Telescope
(SMT), a key instrument of the payload, which will open a new frontier
in transient studies by probing the early optical rise of GRBs with
a response time in seconds for the first time. The SMT employs a
rapidly slewing mirror to redirect the optical axis of the telescope
to a GRB position prior determined by the UFFO Burst Alert Telescope
(UBAT), the other onboard instrument, for the observation and imaging of
X-rays. UFFO/Lomonosov was launched successfully from Vostochny, Russia
on April 28, 2016, and will begin GRB observations after completion of
functional checks of the Lomonosov spacecraft. The concept of early GRB
photon measurements with UFFO was reported in 2012. In this article,
we will report in detail the first mission, UFFO/Lomonosov, for the
rapid response to GRB observations.
Title: UBAT of UFFO/ Lomonosov: The X-Ray Space Telescope to Observe
Early Photons from Gamma-Ray Bursts
Authors: Jeong, S.; Panasyuk, M. I.; Reglero, V.; Connell, P.;
Kim, M. B.; Lee, J.; Rodrigo, J. M.; Ripa, J.; Eyles, C.; Lim, H.;
Gaikov, G.; Jeong, H.; Leonov, V.; Chen, P.; Castro-Tirado, A. J.;
Nam, J. W.; Svertilov, S.; Yashin, I.; Garipov, G.; Huang, M. -H. A.;
Huang, J. -J.; Kim, J. E.; Liu, T. -C.; Petrov, V.; Bogomolov, V.;
Budtz-Jørgensen, C.; Brandt, S.; Park, I. H.
Bibcode: 2018SSRv..214...16J
Altcode:
The Ultra-Fast Flash Observatory (UFFO) Burst Alert and Trigger
Telescope (UBAT) has been designed and built for the localization of
transient X-ray sources such as Gamma Ray Bursts (GRBs). As one of
main instruments in the UFFO payload onboard the Lomonosov satellite
(hereafter UFFO/ Lomonosov), the UBAT's roles are to monitor the X-ray
sky, to rapidly locate and track transient sources, and to trigger the
slewing of a UV/optical telescope, namely Slewing Mirror Telescope
(SMT). The SMT, a pioneering application of rapid slewing mirror
technology has a line of sight parallel to the UBAT, allowing us to
measure the early UV/optical GRB counterpart and study the extremely
early moments of GRB evolution. To detect X-rays, the UBAT utilizes
a 191.1 cm2 scintillation detector composed of Yttrium
Oxyorthosilicate (YSO) crystals, Multi-Anode Photomultiplier Tubes
(MAPMTs), and associated electronics. To estimate a direction vector
of a GRB source in its field of view, it employs the well-known coded
aperture mask technique. All functions are written for implementation
on a field programmable gate array to enable fast triggering and to
run the device's imaging algorithms. The UFFO/ Lomonosov satellite
was launched on April 28, 2016, and is now collecting GRB observation
data. In this study, we describe the UBAT's design, fabrication,
integration, and performance as a GRB X-ray trigger and localization
telescope, both on the ground and in space.
Title: A study of a long duration B9 flare-CME event and associated
shock
Authors: Chandra, R.; Chen, P. F.; Fulara, A.; Srivastava, A. K.;
Uddin, W.
Bibcode: 2018AdSpR..61..705C
Altcode: 2017arXiv171008734C
We present and discuss here the observations of a small long duration
GOES B-class flare associated with a quiescent filament eruption, a
global EUV wave and a CME on 2011 May 11. The event was well observed
by the Solar Dynamics Observatory (SDO), GONG H α , STEREO and Culgoora
spectrograph. As the filament erupted, ahead of the filament we observed
the propagation of EIT wave fronts, as well as two flare ribbons on both
sides of the polarity inversion line (PIL) on the solar surface. The
observations show the co-existence of two types of EUV waves, i.e.,
a fast and a slow one. A type II radio burst with up to the third
harmonic component was also associated with this event. The evolution
of photospheric magnetic field showed flux emergence and cancellation
at the filament site before its eruption.
Title: Photoelectric properties of BiFeO3-BaTiO3 granular films
Authors: TANG, YuanYuan; LIU, YongHong; SUN, Bai; CHEN, Peng
Bibcode: 2018SSPMA..48j7001T
Altcode:
No abstract at ADS
Title: ASAS-SN Transient Classification Report for 2018-01-13
Authors: Bose, S.; Chen, P.; Dong, S.; Bersier, D.; Prieto, J. L.
Bibcode: 2018TNSCR..50....1B
Altcode:
No abstract at ADS
Title: Spectroscopic classification of ASASSN-17rl as type Ib/c
Authors: Bose, S.; Chen, P.; Dong, Subo; Bersier, David; Prieto, J. L.
Bibcode: 2018ATel11163....1B
Altcode:
We report optical spectroscopic observations of supernova candidate
ASASSN-17rl / 2017jea (ATel #11103) done on UT 2017-12-28.47 with
DBSP mounted on the Hale 5m telescope at Palomar Observatory and on
2018-01-11.92 with SPRAT mounted on the 2m Liverpool Telescope.
Title: The ultraviolet spectroscopic evolution of the low-luminosity
tidal disruption event iPTF16fnl
Authors: Brown, J. S.; Kochanek, C. S.; Holoien, T. W. -S.; Stanek,
K. Z.; Auchettl, K.; Shappee, B. J.; Prieto, J. L.; Morrell, N.;
Falco, E.; Strader, J.; Chomiuk, L.; Post, R.; Villanueva, S., Jr.;
Mathur, S.; Dong, S.; Chen, P.; Bose, S.
Bibcode: 2018MNRAS.473.1130B
Altcode: 2017arXiv170402321B
We present the ultraviolet (UV) spectroscopic evolution of a tidal
disruption event (TDE) for the first time. After the discovery of the
nearby TDE iPTF16fnl, we obtained a series of observations with the
Space Telescope Imaging Spectrograph (STIS) onboard the Hubble Space
Telescope (HST). The dominant emission features closely resemble those
seen in the UV spectra of the TDE ASASSN-14li and are also similar to
those of N-rich quasars. There is evolution in the shape and central
wavelength of the dominant emission features over the course of our
observations, such that at early times the lines tend to be broad and
redshifted, while at later times they are narrower and peak near the
wavelengths of their atomic transitions. Like ASASSN-14li, but unlike
N-rich quasars, iPTF16fnl shows neither Mg II 2798 Å nor C III] 1909 Å
emission features. We also present optical photometry and spectroscopy,
which suggest that the complex He II profiles observed in the optical
spectra of many TDEs are in part due to the presence of N III and
C III Wolf-Rayet features, which can potentially serve as probes of
the far-UV when space-based observations are not possible. Finally,
we use Swift X-ray Telescope and Ultraviolet/Optical Telescope (UVOT)
observations to place strong limits on the X-ray emission and determine
the characteristic temperature, radius and luminosity of the emitting
material. We find that iPTF16fnl is subluminous and evolves more
rapidly than other optically discovered TDEs.
Title: ASAS-SN Transient Classification Report for 2017-12-31
Authors: Bose, S.; Chen, P.; Dong, S.
Bibcode: 2017TNSCR1561....1B
Altcode:
No abstract at ADS
Title: ASAS-SN Transient Discovery Report for 2017-12-03
Authors: Chen, P.
Bibcode: 2017TNSTR1364....1C
Altcode:
No abstract at ADS
Title: ASAS-SN Transient Classification Report for 2017-12-31
Authors: Bose, S.; Chen, P.; Dong, S.
Bibcode: 2017TNSCR1508....1B
Altcode:
No abstract at ADS
Title: ASAS-SN Transient Classification Report for 2017-12-31
Authors: Bose, S.; Chen, P.; Dong, S.
Bibcode: 2017TNSCR1506....1B
Altcode:
No abstract at ADS
Title: A circular white-light flare with impulsive and gradual
white-light kernels
Authors: Hao, Q.; Yang, K.; Cheng, X.; Guo, Y.; Fang, C.; Ding, M. D.;
Chen, P. F.; Li, Z.
Bibcode: 2017NatCo...8.2202H
Altcode: 2017arXiv171207279H
White-light flares are the flares with emissions visible in the
optical continuum. They are thought to be rare and pose the most
stringent requirements in energy transport and heating in the lower
atmosphere. Here we present a nearly circular white-light flare on
10 March 2015 that was well observed by the Optical and Near-infrared
Solar Eruption Tracer and Solar Dynamics Observatory. In this flare,
there appear simultaneously both impulsive and gradual white-light
kernels. The generally accepted thick-target model would be responsible
for the impulsive kernels but not sufficient to interpret the gradual
kernels. Some other mechanisms including soft X-ray backwarming or
downward-propagating Alfvén waves, acting jointly with electron beam
bombardment, provide a possible interpretation. However, the origin of
this kind of white-light kernel is still an open question that induces
more observations and researches in the future to decipher it.
Title: Measurement of the real dielectric permittivity epsilon_r of
glacial ice
Authors: Allison, P.; Archambault, S.; Auffenberg, J.; Bard,
R.; Beatty, J. J.; Beheler-Amass, M.; Besson, D. Z.; Beydler, M.;
Brabec, C.; Chen, C. -C.; Chen, C. -H.; Chen, P.; Christenson, A.;
Clark, B. A.; Connolly, A.; Cremonesi, L.; Deaconu, C.; Duvernois,
M.; Friedman, L.; Gaior, R.; Gorham, P. W.; Hanson, J.; Hanson, K.;
Haugen, J.; Hoffman, K. D.; Hong, E.; Hsu, S. -Y.; Hu, L.; Huang,
J. -J.; Huang, M. -H. A.; Ishihara, A.; Karle, A.; Kelley, J. L.;
Khandelwal, R.; Kim, M. -C.; Kravchenko, I.; Kuwabara, T.; Landsman,
H.; Laundrie, A.; Li, C. -J.; Liu, T. C.; Lu, M. -Y.; Mase, K.;
Meures, T.; Nam, J.; Nichols, R. J.; Nir, G.; Novikov, A.; Oberla,
E.; O'Murchadha, A.; Pan, Y.; Pfendner, C.; Ratzlaff, K.; Relich,
M.; Roth, J.; Sandstrom, P.; Seckel, D.; Shiao, Y. -S.; Shultz, A.;
Song, M.; Touart, J.; Varner, G. S.; Vieregg, A.; Wang, M. -Z.; Wang,
S. -H.; Wissel, S.; Yang, Y.; Yoshida, S.; Young, R.
Bibcode: 2017arXiv171203301A
Altcode:
Using data collected by the Askaryan Radio Array (ARA) experiment
at the South Pole, we have used long-baseline propagation of
radio-frequency signals to extract information on the radio-frequency
index-of-refraction in South Polar ice. Owing to the increasing ice
density over the upper 150--200 meters, rays are observed along two,
nearly parallel paths, one of which is direct and a second which
refracts through an inflection point, with differences in both
arrival time and arrival angle that can be used to constrain the
neutrino properties. We also observe indications, for the first time,
of radio-frequency ice birefringence for signals propagating along
predominantly horizontal trajectories, corresponding to an asymmetry of
order 0.1% between the ordinary and extra-ordinary paths, numerically
compatible with previous measurements of birefringent asymmetries for
vertically-propagating radio-frequency signals at South Pole. Taken
together, these effects offer the possibility of redundantly measuring
the range from receiver to a neutrino interaction in Antarctic ice,
if receiver antennas are deployed at shallow (25 m<z<100 m)
depths. Such range information is essential in determining both the
neutrino energy, as well as the incident neutrino direction.
Title: ASAS-SN Transient Discovery Report for 2017-11-19
Authors: Nicholls, B.; Brimacombe, J.; Chen, P.; Dong, S.; Stanek,
K. Z.
Bibcode: 2017TNSTR1275....1N
Altcode:
No abstract at ADS
Title: Slewing mirror telescope of the UFFO-pathfinder: first report
on performance in space
Authors: Gaikov, G.; Jeong, S.; Agaradahalli, V. G.; Park, I. H.;
Budtz-Jøgensen, C.; Castro-Tirado, A. J.; Chen, P.; Jeong, H. M.;
Kim, J. E.; Kim, M. B.; Kim, S. W.; Lee, J.; Leonov, V.; Nam, J. W.;
Panasyuk, M. I.; Petrov, V.; Reglero, V.; Ripa, J.; Svertilov, S. I.;
Tumarina, M.; Yashin, I.
Bibcode: 2017OExpr..2529143G
Altcode:
To observe the early optical emissions from gamma ray bursts (GRBs),
we built the Slew Mirror Telescope. It utilizes a 150 mm motorized
mirror to redirect incoming photons from astrophysical objects within
seconds and to track them as compensating satellite movements. The SMT
is a major component of the UFFO-pathfinder payload, which was launched
on April 28, 2016, onboard the Lomonosov satellite. For the first time,
the slewing mirror system has been proven for the precision tracking
of astrophysical objects during space operation. We confirmed that the
SMT has 1.4 seconds of response time to the X-gamma-ray trigger, and
is able to compensate for satellite drift and to track astrophysical
objects with magnitudes from 7 to 18.
Title: ASAS-SN Transient Classification Report for 2017-10-16
Authors: Bose, S.; Morrell, N.; Dressler, A.; Kollmeier, J.; Dong,
S.; Chen, P.; Prieto, J. L.
Bibcode: 2017TNSCR1126....1B
Altcode:
No abstract at ADS
Title: ASAS-SN Transient Discovery Report for 2017-10-11
Authors: Kiyota, S.; Brimacombe, J.; Chen, P.; Stanek, K. Z.
Bibcode: 2017TNSTR1099....1K
Altcode:
No abstract at ADS
Title: ASAS-SN Transient Classification Report for 2017-10-25
Authors: Bose, S.; Seibert, M.; Prieto, J. L.; Shappee, B.; Dong,
S.; Chen, P.
Bibcode: 2017TNSCR1166....1B
Altcode:
No abstract at ADS
Title: A reexamination of a filament oscillation event on 2013
March 15
Authors: Chen, Jialin; Xie, Wenbin; Zhou, Yuhao; Yang, Kai; Ouyang,
Yu; Chen, P. F.
Bibcode: 2017Ap&SS.362..165C
Altcode:
The key element in the research of solar activities is the coronal
magnetic field, which is however difficult to measure directly. Filament
(or prominence) oscillations offer a new approach to derive important
information of the coronal magnetic field, which is called prominence
seismology. However, it is vital to determine the oscillation mode
before applying the prominence seismology since for a given magnetic
structure of a filament, the two different modes of oscillation, namely,
the longitudinal and transverse, have different eigen frequencies. In
low-resolution observations, it is hard to distinguish the oscillation
mode since both modes of oscillations are associated with lateral
displacements, and the subtle difference between the two modes becomes
unresolvable. On 2013 March 15, there is a filament oscillation event
with a period of ∼63 minutes and a decay timescale of ∼105 minutes,
which was explained in the literature to be a transverse oscillation
or a mixture of both transversal and longitudinal components with the
same period. With the analysis of the high-resolution SDO/AIA data,
we reexamine the filament oscillation event, and argue that this event
is a longitudinal oscillation. We tentatively propose a new method on
how to identify the oscillation mode when the observational resolution
is not so high. A numerical simulation is also provided in order to
match the observations, which leads to the ratio between the depth
and the width of the magnetic dip being 0.1.
Title: ASAS-SN Transient Classification Report for 2017-09-28
Authors: Bose, S.; Dong, S.; Chen, P.; Prieto, J. L.
Bibcode: 2017TNSCR1043....1B
Altcode:
No abstract at ADS
Title: Global model of zenith tropospheric delay proposed based on
EOF analysis
Authors: Sun, Langlang; Chen, Peng; Wei, Erhu; Li, Qinzheng
Bibcode: 2017AdSpR..60..187S
Altcode:
Tropospheric delay is one of the main error budgets in Global
Navigation Satellite System (GNSS) measurements. Many empirical
correction models have been developed to compensate this delay, and
models which do not require meteorological parameters have received
the most attention. This study established a global troposphere zenith
total delay (ZTD) model, called Global Empirical Orthogonal Function
Troposphere (GEOFT), based on the empirical orthogonal function (EOF,
also known as geographically weighted PCAs) analysis method and the
Global Geodetic Observing System (GGOS) Atmosphere data from 2012 to
2015. The results showed that ZTD variation could be well represented
by the characteristics of the EOF base function Ek
and associated coefficients Pk. Here, E1
mainly signifies the equatorial anomaly; E2 represents
north-south asymmetry, and E3 and E4 reflects
regional variation. Moreover, P1 mainly reflects annual
and semiannual variation components; P2 and P3
mainly contains annual variation components, and P4 displays
semiannual variation components. We validated the proposed GEOFT model
using tropospheric delay data of GGOS ZTD grid data and the tropospheric
product of the International GNSS Service (IGS) over the year 2016. The
results showed that GEOFT model has high accuracy with bias and RMS
of -0.3 and 3.9 cm, respectively, with respect to the GGOS ZTD data,
and of -0.8 and 4.1 cm, respectively, with respect to the global IGS
tropospheric product. The accuracy of GEOFT demonstrating that the use
of the EOF analysis method to characterize ZTD variation is reasonable.
Title: Comet C/2017 O1
Authors: Brimacombe, J.; Prieto, J.; Kadota, K.; Masi, G.; Masi, U.;
Ventre, G.; Sicoli, P.; Shappee, B.; Soulier, J. -F.; Hambsch, F. -J.;
Bryssinck, E.; Lutkenhoner, B.; Tuten, J. L.; Bell, C.; Abreu, D.;
Micheli, M.; Koschny, D.; Busch, M.; Schwab, E.; Knoefel, A.; Hills,
K.; Lister, T.; Greenstreet, S.; Gomez, E.; MacFarlane, J.; Urbanik,
M.; Ligustri, R.; Suzuki, M.; Tilley, S. M.; Guido, E.; Sato, H.;
Mattiazzo, M.; Chen, P.; Maury, A.; Vanssay, J. -B.; de Vanssay,
J. -B.; Bosch, J. -G.; Jacques, C.; Pimentel, E.; Barros, J.; Lipunov,
V.; Gorbovskoy, E.; Rebolo, R.; Israelyan, G.; Serra-Ricart, M.;
Lodieu, N.; Balanutsa, P.; Kuznetsov, A.; Tiurina, N.; Gress, O.;
Chazov, V.; Ivanov, K.; Vlasenko, D.; Williams, G. V.
Bibcode: 2017MPEC....O...45B
Altcode:
No abstract at ADS
Title: Antarctic Surface Reflectivity Measurements from the ANITA-3
and HiCal-1 Experiments
Authors: Gorham, P. W.; Allison, P.; Banerjee, O.; Beatty, J. J.;
Belov, K.; Besson, D. Z.; Binns, W. R.; Bugaev, V.; Cao, P.; Chen,
C.; Chen, P.; Clem, J. M.; Connolly, A.; Dailey, B.; Dasgupta, P.;
Deaconu, C.; Cremonesi, L.; Dowkontt, P. F.; Fox, B. D.; Gordon,
J.; Hill, B.; Hupe, R.; Israel, M. H.; Jain, P.; Kowalski, J.; Lam,
J.; Learned, J. G.; Liewer, K. M.; Liu, T. C.; Matsuno, S.; Miki,
C.; Mottram, M.; Mulrey, K.; Nam, J.; Nichol, R. J.; Novikov, A.;
Oberla, E.; Prohira, S.; Rauch, B. F.; Romero-Wolf, A.; Rotter, B.;
Ratzlaff, K.; Russell, J.; Saltzberg, D.; Seckel, D.; Schoorlemmer,
H.; Stafford, S.; Stockham, J.; Stockham, M.; Strutt, B.; Tatem, K.;
Varner, G. S.; Vieregg, A. G.; Wissel, S. A.; Wu, F.; Young, R.
Bibcode: 2017JAI.....640002G
Altcode: 2017arXiv170300415G
The primary science goal of the NASA-sponsored ANITA project
is measurement of ultra-high energy neutrinos and cosmic rays,
observed via radio-frequency signals resulting from a neutrino or
cosmic ray interaction with terrestrial matter (e.g. atmospheric or
ice molecules). Accurate inference of the energies of these cosmic
rays requires understanding the transmission/reflection of radio wave
signals across the ice-air boundary. Satellite-based measurements of
Antarctic surface reflectivity, using a co-located transmitter and
receiver, have been performed more-or-less continuously for the last
few decades. Our comparison of four different reflectivity surveys,
at frequencies ranging from 2 to 45GHz and at near-normal incidence,
yield generally consistent maps of high versus low reflectivity,
as a function of location, across Antarctica. Using the Sun
as an RF source, and the ANITA-3 balloon borne radio-frequency
antenna array as the RF receiver, we have also measured the surface
reflectivity over the interval 200-1000MHz, at elevation angles of
12-30∘. Consistent with our previous measurement using ANITA-2, we
find good agreement, within systematic errors (dominated by antenna
beam width uncertainties) and across Antarctica, with the expected
reflectivity as prescribed by the Fresnel equations. To probe low
incidence angles, inaccessible to the Antarctic Solar technique and
not probed by previous satellite surveys, a novel experimental approach
(“HiCal-1”) was devised. Unlike previous measurements, HiCal-ANITA
constitute a bi-static transmitter-receiver pair separated by hundreds
of kilometers. Data taken with HiCal, between 200 and 600MHz shows
a significant departure from the Fresnel equations, constant with
frequency over that band, with the deficit increasing with obliquity
of incidence, which we attribute to the combined effects of possible
surface roughness, surface grain effects, radar clutter and/or shadowing
of the reflection zone due to Earth curvature effects. We discuss the
science implications of the HiCal results, as well as improvements
planned for HiCal-2, preparing for launch in December 2016.
Title: ASAS-SN photometry of the Galactic nova TCP J17394608-2457555
Authors: Strader, J.; Chomiuk, L.; Brown, J. S.; Stanek, K. Z.;
Holoien, T. W. -S.; Kochanek, C. S.; Shields, J.; Thompson, T. A.;
Shappee, B. J.; Prieto, J. L.; Bersier, D.; Dong, S.; Bose, S.; Chen,
P.; Brimacombe, J.
Bibcode: 2017ATel10367....1S
Altcode: 2017ATel.10367...1S
We report ASAS-SN photometry of the Galactic nova TCP J17394608-2457555
(CBAT; ATel #10366). ASAS-SN recovered the source with a first detection
(V=14.9) on Apr 21.43 UT, 17 days before the discovery by K. Itagaki.
Title: Solar Filament Longitudinal Oscillations along a Magnetic
Field Tube with Two Dips
Authors: Zhou, Yu-Hao; Zhang, Li-Yue; Ouyang, Y.; Chen, P. F.; Fang, C.
Bibcode: 2017ApJ...839....9Z
Altcode: 2017arXiv170306560Z
Large-amplitude longitudinal oscillations of solar filaments have
been observed and explored for more than ten years. Previous studies
are mainly based on the one-dimensional rigid flux tube model with
a single magnetic dip. However, it has been noted that there might
be two magnetic dips, and hence two threads, along one magnetic
field line. Following previous work, we intend to investigate the
kinematics of the filament longitudinal oscillations when two threads
are magnetically connected, which is done by solving one-dimensional
radiative hydrodynamic equations with the numerical code MPI-AMRVAC. Two
different types of perturbations are considered, and the difference
from previous works resulting from the interaction of the two filament
threads is investigated. We find that even with the inclusion of the
thread-thread interaction, the oscillation period is modified weakly,
by at most 20% compared to the traditional pendulum model with one
thread. However, the damping timescale is significantly affected by
the thread-thread interaction. Hence, we should take it into account
when applying the consistent seismology to the filaments where two
threads are magnetically connected.
Title: Constraints on the ultra-high-energy neutrino flux from
Gamma-Ray bursts from a prototype station of the Askaryan radio array
Authors: Allison, P.; Auffenberg, J.; Bard, R.; Beatty, J. J.;
Besson, D. Z.; Bora, C.; Chen, C. -C.; Chen, P.; Connolly, A.; Davies,
J. P.; DuVernois, M. A.; Fox, B.; Gorham, P. W.; Hanson, K.; Hill,
B.; Hoffman, K. D.; Hong, E.; Hu, L. -C.; Ishihara, A.; Karle, A.;
Kelley, J.; Kravchenko, I.; Landsman, H.; Laundrie, A.; Li, C. -J.;
Liu, T.; Lu, M. -Y.; Maunu, R.; Mase, K.; Meures, T.; Miki, C.;
Nam, J.; Nichol, R. J.; Nir, G.; Ó Murchadha, A.; Pfendner, C. G.;
Ratzlaff, K.; Rotter, B.; Sandstrom, P.; Seckel, D.; Shultz, A.; Song,
M.; Stockham, J.; Stockham, M.; Sullivan, M.; Touart, J.; Tu, H. -Y.;
Varner, G. S.; Yoshida, S.; Young, R.; Bustamante, M.; Guetta, D.
Bibcode: 2017APh....88....7A
Altcode: 2015arXiv150700100A
We report on a search for ultra-high-energy (UHE) neutrinos from
gamma-ray bursts (GRBs) in the data set collected by the Testbed station
of the Askaryan Radio Array (ARA) in 2011 and 2012. From 57 selected
GRBs, we observed no events that survive our cuts, which is consistent
with 0.12 expected background events. Using NeuCosmA as a numerical
GRB reference emission model, we estimate upper limits on the prompt
UHE GRB neutrino fluence and quasi-diffuse flux from 107
to 1010 GeV. This is the first limit on the prompt UHE GRB
neutrino quasi-diffuse flux above 107 GeV.
Title: Magnetic Separatrix as the Source Region of the Plasma Supply
for an Active-region Filament
Authors: Zou, P.; Fang, C.; Chen, P. F.; Yang, K.; Cao, Wenda
Bibcode: 2017ApJ...836..122Z
Altcode: 2017arXiv170101526Z
Solar filaments can be formed via chromospheric evaporation followed
by condensation in the corona or by the direct injection of cool
plasma from the chromosphere to the corona. We here confirm with
high-resolution Hα data observed by the 1.6 m New Solar Telescope of
the Big Bear Solar Observatory on 2015 August 21 that an active-region
filament is maintained by the continuous injection of cold chromospheric
plasma. We find that the filament is rooted along a bright ridge in Hα,
which corresponds to the intersection of a magnetic quasi-separatrix
layer with the solar surface. This bright ridge consists of many
small patches whose sizes are comparable to the width of the filament
threads. It is found that upflows originate from the brighter patches
of the ridge, whereas the downflows move toward the weaker patches of
the ridge. The whole filament is composed of two opposite-direction
streams, implying that longitudinal oscillations are not the only
cause of the counterstreamings, and unidirectional siphon flows with
alternative directions are another possibility.
Title: VizieR Online Data Catalog: Follow-up of probable young star
ASASSN-15qi (Herczeg+, 2016)
Authors: Herczeg, G. J.; Dong, S.; Shappee, B. J.; Chen, P.;
Hillenbrand, L. A.; Jose, J.; Kochanek, C. S.; Prieto, J. L.;
Stanek, K. Z.; Kaplan, K.; Holoien, T. -S.; Mairs, S.; Johnstone,
D.; Gully-Santiago, M.; Zhu, Z.; Smith, M. C.; Bersier, D.; Mulders,
G. D.; Filippenko, A. V.; Ayani, K.; Brimacombe, J.; Brown, J. S.;
Connelley, M.; Harmanen, J.; Itoh, R.; Kawabata, K. S.; Maehara, H.;
Takata, K.; Yuk, H.; Zheng, W.
Bibcode: 2017yCat..18310133H
Altcode:
The outburst of ASASSN-15qi (2MASS J22560882+5831040) occurred on
JD2457298 (2015 October 2; UTC dates are used herein). The All-Sky
Automated Survey for Supernovae (ASAS-SN) is an all-sky V-band
transient survey with a limiting magnitude of ~17. ASAS-SN photometry of
ASASSN-15qi was obtained from two different telescopes on Haleakala,
Hawaii with intervals of one to three days. ASAS-SN photometry is
listed in Table 2. Archival photometry, ground-based optical
photometry with Las Cumbres Observatory Global Telescope Network
(LCOGT) 1m telescope at McDonald Observatory between 2015 October 23
and December 23 and at the Liverpool Telescope on 2016 April 26 and
June 11, Swift/UVOT photometry on 2015 October 12 (ID 00034098001)
and 2015 December 27 (ID 00034098002), NIR photometry with the NOTCam
camera at the Nordic Optical Telescope (NOT) on 2015 December 22
and Spitzer/IRAC MIR photometry on 2006 December 29 (Program ID
30734, PI Donald Figer) and James Clerk Maxwell Telescope (JCMT)
SCUBA2 submillimeter observations of ASASSN-15qi on 2015 November 5
and optical and NIR spectroscopy observations are also described in
section 2. (1 data file).
Title: Cosmic ray effect on the X-ray Trigger Telescope of
UFFO/Lomonosov using YSO scintillation crystal array in space
Authors: Kim, M. B.; Jeong, S.; Jeong, H. M.; Leonov, V.; Lee, J.;
Park, I. H.; Amelushkin, A. M.; Barinova, V. O.; Bogomolov, A. V.;
Bogomolov, V. V.; Brandt, S.; Budtz-Jørgensen, C.; Castro-Tirado,
A. J.; Chen, P.; Connell, P.; Garipov, G.; Gorbovskoy, E. S.; Dzhioeva,
N. L.; Eyles, C.; Iyudin, A. F.; Huang, M. H. A.; Kalegaev, V. V.;
Kasarjan, P. S.; Kim, J. E.; Kornilov, V. G.; Kuznetsova, E. A.;
Lim, H.; Lipunov, V. M.; Liu, T. C.; Myagkova, I. N.; Nam, J. W.;
Panasyuk, M. I.; Panchenko, M. I.; Petrov, V. L.; Prokhorov, A. V.;
Reglero, V.; Ripa, J.; Shustova, A. N.; Rodrigo, J. M.; Svertilov,
S. I.; Tyurina, N. V.; Yashin, I. V.
Bibcode: 2017ICRC...35..218K
Altcode: 2017PoS...301..218K
UFFO Burst Alert and Trigger telescope (UBAT) is the X-ray trigger
telescope of UFFO/Lomonosov to localize X-ray source with coded mask
method and X-ray detector. Its Xray detector is made up of 36 8×8
pixels Yttrium OxyorthoSilicate (Y2SiO5:Ce, YSO) scintillation crystal
arrays and 36 64-channel Multi-Anode PhotoMultiplier Tubes (MAPMTs)
for space mission. Its effective detection area is 161cm^2 and energy
range is several keV to 150 keV. It was successfully launched in April
28, 2016. In several calibration run, we got several X-ray background
data. We already knew X-ray background flux is 2-3 counts/cm^2/sec
in space.However our X-ray background data shows approximately 7-8
times higher than what we know. There are many candidates to explain
high X-ray background count in space. One of candidates is cosmic
ray. We will report cosmic ray effect on the X-ray detector using YSO
scintillation crystal arrays in space.
Title: The status of the second station of Taiwan Astroparticle
Radiowave Observatory for Geo-synchrotron Emissions (TAROGE-II)
Authors: Liu, T. C.; Chen, C. -H.; Chen, C. -W.; Chen, P.; Chen,
Y. -C.; Chen, Y. -C.; Hsu, S. -Y.; Huang, J. -J.; Huang, M. -H. A.;
Nam, J.; Ripa, J.; Shiao, Y. -S.; Wang, M. -Z.; Wang, S. -H.
Bibcode: 2017ICRC...35..234L
Altcode: 2017PoS...301..234L
Taiwan Astroparticle Radiowave Observatory (TAROGE) is an antenna array
on the cliff of Taiwan's East coast to monitor ultra-high energy cosmic
rays (UHECR, > 10^19 eV). The antennas face the Pacific Ocean to
detect radiowave signals emitted by the UHECR-induced air shower. The
unique terrain of TAROGE site allows the antennas to collect both
the direct-emission and the ocean-reflected radiowave signals induced
by UHECR. So far two TAROGE stations have been deployed. The second
TAROGE station (TAROGE-II), which consists of 6 dual-polarization
log-periodic dipole antennas (110-500 MHz), was installed on the
1100 m elevation near TAROGE-I in December of 2016. In this report,
we introduce the basic concept of TAROGE, its data tacking, expected
sensitivity, and future prospect.
Title: Comparison cosmic ray irradiation simulation and particle
beam test on UFFO Burst Alert & Trigger telescope(UBAT) detectors
Authors: Jeong, H. M.; Jeong, S.; Kim, M. B.; Lee, J.; Park, I. H.;
Amelushkin, A. M.; Barinova, V. O.; Bogomolov, A. V.; Bogomolov,
V. V.; Brandt, S.; Budtz-Jørgensen, C.; Castro-Tirado, A. J.; Chen,
P.; Connell, P.; Dzhioeva, N. L.; Eyles, C.; Garipov, G.; Gorbovskoy,
E. S.; Huang, M. H. A.; Iyudin, A. F.; Kalegaev, V. V.; Kasarjan,
P. S.; Kim, J. E.; Kornilov, V. G.; Kuznetsova, E. A.; Lim, H.;
Lipunov, V. M.; Liu, T. C.; Myagkova, I. N.; Nam, J. W.; Panasyuk,
M. I.; Panchenko, M. I.; Petrov, V. L.; Prokhorov, A. V.; Reglero,
V.; Ripa, J.; Rodrigo, J. M.; Shustova, A. N.; Svertilov, S. I.;
Tyurina, N. V.; Yashin, I. V.
Bibcode: 2017ICRC...35..219J
Altcode: 2017PoS...301..219J
Ultra-Fast Flash Observatory pathfinder(UFFO-p) was launched onboard
Lomonosov on 28th of April, 2016, and now is under various types
of calibration for detection of Gamma Ray Bursts (GRBs). Since last
September UFFO-p has taken X-ray data in space with UFFO Burst Alert
& Trigger telescope (UBAT), those X-rays are mostly diffused
backgrounds however, the rate turns out to be higher than expected by
a factor of three. We assumed cosmic rays can contribute by making the
count rate higher. We did such a simulation to investigate the effect
of cosmic rays. In December 2016, we irradiated fragmented high energy
heavy ions at CERN on the UBAT detector. We will report the result of
comparison between simulation and beam test.
Title: Statistical and theoretical studies of flares from Sagittarius
A*
Authors: Li, Ya-Ping; Yuan, Qiang; Wang, Q. Daniel; Chen, P. F.;
Neilsen, Joseph; Fang, Taotao; Zhang, Shuo; Dexter, Jason
Bibcode: 2017IAUS..322...31L
Altcode:
Multi-wavelength flares have routinely been observed from the
supermassive black hole, Sagittarius A* (Sgr A*), at our Galactic
center. The nature of these flares remains largely unclear, despite many
theoretical models. We study the statistical properties of the Sgr A*
X-ray flares and find that they are consistent with the theoretical
prediction of the self-organized criticality system with the spatial
dimension S = 3. We suggest that the X-ray flares represent plasmoid
ejections driven by magnetic reconnection (similar to solar flares)
in the accretion flow onto the black hole. Motivated by the statistical
results, we further develop a time-dependent magnetohydrodynamic (MHD)
model for the multi-band flares from Sgr A* by analogy with models of
solar flares/coronal mass ejections (CMEs). We calculate the X-ray,
infrared flare light curves, and the spectra, and find that our model
can explain the main features of the flares.
Title: The Slewing Mirror Telescope of UFFO-Pathfinder: first
performance report in space
Authors: Gaikov, G.; Jeong, S.; Agaradahalli, V. G.; Park, I. H.;
Amelushkin, A. M.; Barinova, V. O.; Bogomolov, A. V.; Bogomolov, V. V.;
Budtz-Jørgensen, C.; Castro-Tirado, A. J.; Chen, P.; Dzhioeva, N. L.;
Gorbovskoy, E. S.; Iyudin, A. F.; Kalegaev, V. V.; Kasarjan, P. S.;
Jeong, H. M.; Kim, J. E.; Kim, M. B.; Kim, S. W.; Kornilov, V. G.;
Kuznetsova, E. A.; Lee, J. H.; Lipunov, V. M.; Myagkova, I. N.; Nam,
J. W.; Panasyuk, M. I.; Panchenko, M. I.; Petrov, V.; Prokhorov, A. V.;
Reglero, V.; Shustova, A. N.; Svertilov, S.; Tyurina, N. V.; Yashin, I.
Bibcode: 2017ICRC...35..774G
Altcode: 2017PoS...301..774G
No abstract at ADS
Title: Modeling the plasmasphere based on LEO satellites onboard
GPS measurements
Authors: Chen, Peng; Yao, Yibin; Li, Qinzheng; Yao, Wanqiang
Bibcode: 2017JGRA..122.1221C
Altcode:
The plasmasphere, which is located above the ionosphere, is a
significant component of Earth's atmosphere. A global plasmaspheric
model was constructed using the total electron content (TEC) along the
signal propagation path calculated using onboard Global Positioning
System observations from the Constellation Observing System for
Meteorology, Ionosphere, and Climate (COSMIC) and MetOp-A, provided by
the COSMIC Data Analysis and Archive Center (CDAAC). First, the global
plasmaspheric model was established using only COSMIC TEC, and a set of
MetOp-A TEC provided by CDAAC served for external evaluation. Results
indicated that the established model using only COSMIC data is highly
accurate. Then, COSMIC and MetOp-A TEC were combined to produce a new
global plasmaspheric model. Finally, the variational characteristics
of global plasmaspheric electron content with latitude, local time,
and season were investigated using the global plasmaspheric model
established in this paper.
Title: Understanding the Physical Nature of Coronal "EIT Waves"
Authors: Long, D. M.; Bloomfield, D. S.; Chen, P. F.; Downs, C.;
Gallagher, P. T.; Kwon, R. -Y.; Vanninathan, K.; Veronig, A. M.;
Vourlidas, A.; Vršnak, B.; Warmuth, A.; Žic, T.
Bibcode: 2017SoPh..292....7L
Altcode: 2016arXiv161105505L
For almost 20 years the physical nature of globally propagating waves in
the solar corona (commonly called "EIT waves") has been controversial
and subject to debate. Additional theories have been proposed over the
years to explain observations that did not agree with the originally
proposed fast-mode wave interpretation. However, the incompatibility
of observations made using the Extreme-ultraviolet Imaging Telescope
(EIT) onboard the Solar and Heliospheric Observatory with the fast-mode
wave interpretation was challenged by differing viewpoints from the twin
Solar Terrestrial Relations Observatory spacecraft and data with higher
spatial and temporal resolution from the Solar Dynamics Observatory. In
this article, we reexamine the theories proposed to explain EIT waves
to identify measurable properties and behaviours that can be compared
to current and future observations. Most of us conclude that the
so-called EIT waves are best described as fast-mode large-amplitude
waves or shocks that are initially driven by the impulsive expansion
of an erupting coronal mass ejection in the low corona.
Title: A Statistical Study of Flare Productivity Associated with
Sunspot Properties in Different Magnetic Types of Active Regions
Authors: Yang, Ya-Hui; Hsieh, Min-Shiu; Yu, Hsiu-Shan; Chen, P. F.
Bibcode: 2017ApJ...834..150Y
Altcode:
It is often believed that intense flares preferentially originate from
the large-size active regions (ARs) with strong magnetic fields and
complex magnetic configurations. This work investigates the dependence
of flare activity on the AR properties and clarifies the influence of
AR magnetic parameters on the flare productivity, based on two data
sets of daily sunspot and flare information as well as the GOES soft
X-ray measurements and HMI vector magnetograms. By considering the
evolution of magnetic complexity, we find that flare behaviors are
quite different in the short- and long-lived complex ARs and the ARs
with more complex magnetic configurations are likely to host more
impulsive and intense flares. Furthermore, we investigate several
magnetic quantities and perform the two-sample Kolmogorov-Smirnov
test to examine the similarity/difference between two populations in
different types of ARs. Our results demonstrate that the total source
field strength on the photosphere has a good correlation with the
flare activity in complex ARs. It is noted that intense flares tend
to occur at the regions of strong source field in combination with an
intermediate field-weighted shear angle. This result implies that the
magnetic free energy provided by a complex AR could be high enough to
trigger a flare eruption even with a moderate magnetic shear on the
photosphere. We thus suggest that the magnetic free energy represented
by the source field rather than the photospheric magnetic complexity
is a better quantity to characterize the flare productivity of an AR,
especially for the occurrence of intense flares.
Title: Chirality and Magnetic Configurations of Solar Filaments
Authors: Ouyang, Y.; Zhou, Y. H.; Chen, P. F.; Fang, C.
Bibcode: 2017ApJ...835...94O
Altcode: 2016arXiv161201054O
It has been revealed that the magnetic topology in the solar
atmosphere displays hemispheric preference, i.e., helicity is
mainly negative/positive in the northern/southern hemispheres,
respectively. However, the strength of the hemispheric rule and
its cyclic variation are controversial. In this paper, we apply a
new method based on the filament drainage to 571 erupting filaments
from 2010 May to 2015 December in order to determine the filament
chirality and its hemispheric preference. It is found that 91.6%
of our sample of erupting filaments follows the hemispheric rule of
helicity sign. It is also found that the strength of the hemispheric
preference of the quiescent filaments decreases slightly from ∼97%
in the rising phase to ∼85% in the declining phase of solar cycle 24,
whereas the strength of the intermediate filaments keeps a high value
around 96 ± 4% at all times. Only the active-region filaments show
significant variations. Their strength of the hemispheric rule rises
from ∼63% to ∼95% in the rising phase, and keeps a high value of
82% ± 5% during the declining phase. Furthermore, during a half-year
period around the solar maximum, their hemispheric preference totally
vanishes. Additionally, we also diagnose the magnetic configurations
of the filaments based on our indirect method and find that in our
sample of erupting events, 89% are inverse-polarity filaments with
a flux rope magnetic configuration, whereas 11% are normal-polarity
filaments with a sheared arcade configuration.
Title: Chaos-induced resistivity of collisionless magnetic
reconnection in the presence of a guide field
Authors: Shang, Meng; Wu, De-Jin; Chen, Ling; Chen, Peng-Fei
Bibcode: 2017RAA....17....3S
Altcode:
One of the most puzzling problems in astrophysics is to understand
the anomalous resistivity in collisionless magnetic reconnection
that is believed extensively to be responsible for the energy
release in various eruptive phenomena. The magnetic null point in
the reconnecting current sheet, acting as a scattering center, can
lead to chaotic motions of particles in the current sheet, which
is one of the possible mechanisms for anomalous resistivity and is
called chaos-induced resistivity. In many interesting cases, however,
instead of the magnetic null point, there is a nonzero magnetic field
perpendicular to the merging field lines, usually called the guide
field, whose effect on chaos-induced resistivity has been an open
problem. By use of the test particle simulation method and statistical
analysis, we investigate chaos-induced resistivity in the presence
of a constant guide field. The characteristics of particle motion
in the reconnecting region, in particular, the chaotic behavior of
particle orbits and evolving statistical features, are analyzed. The
results show that as the guide field increases, the radius of the
chaos region increases and the Lyapunov index decreases. However, the
effective collision frequency, and hence the chaos-induced resistivity,
reach their peak values when the guide field approaches half of the
characteristic strength of the reconnection magnetic field. The presence
of a guide field can significantly influence the chaos of the particle
orbits and hence the chaos-induced resistivity in the reconnection
sheet, which decides the collisionless reconnection rate. The present
result is helpful for us to understand the microphysics of anomalous
resistivity in collisionless reconnection with a guide field.
Title: The instruments of sFLASH experiment
Authors: Shin, B.; Atwood, S.; Belov, K.; Belz, J.; Chen, P.; Field,
C.; Fukushima, M.; Haste, C.; Huang, J.; Huey, H.; Liu, T. C.; Ivanov,
D.; Jobe, K.; Jui, C.; Nam, J.; Naudet, C.; Matthews, J. N.; Potts,
M.; Reil, K.; Saltzberg, D.; Sokolsky, P.; Thomas, S.; Thomson, G.;
Wang, S.; Sflash Collaboration
Bibcode: 2017ICRC...35..407S
Altcode: 2017PoS...301..407S
No abstract at ADS
Title: In-Situ Calibration of UFFO/Lomonosov for Observation of GRBs
Authors: Jeong, S.; Park, I. H.; Bogomolov, V.; Brandt, S.;
Budtz-Jørgensen, C.; Castro-Tirado, A. J.; Chang, S. -H.; Chang,
Y. Y.; Chen, P.; Chen, C. -R.; Chen, C. -W.; Choi, H. S.; Connell, P.;
Eyles, C.; Gaikov, G.; Garipov, G.; Huang, M. -H. A.; Jeong, H. M.;
Kim, J. E.; Kim, M. B.; Kim, S. -W.; Lee, H. K.; Lee, J.; Lim, H.; Lin,
C. -Y.; Liu, T. C.; Nam, J. W.; Panasyuk, M. I.; Petrov, V.; Reglero,
V.; Ripa, J.; Rodrigo, J. M.; Svertilov, S.; Wang, Z.; Yashin, I.
Bibcode: 2017ICRC...35..821J
Altcode: 2017PoS...301..821J
The UFFO/Lomonosov has been successfully launched into Sun synchronous
orbit and is operational through tests and calibrations since its
launch on Apr. 28, 2016. As a pathfinder of UFFO, it will be the
first space instrument to use a fast slewing mirror which reduce the
trigger latency of optical telescope, less than a second, to explore
early time domain of GRB evolution. In this article, we will report
in detail the first mission, UFFO/Lomonosov, for the rapid response
to observe early photons from GRBs in orbit.
Title: On the coseismic ionospheric disturbances after the Nepal
Mw7.8 earthquake on April 25, 2015 using GNSS observations
Authors: Chen, Peng; Yao, Yibin; Yao, Wanqiang
Bibcode: 2017AdSpR..59..103C
Altcode:
Nepal Mw7.8 earthquake occurred at 06:11:26 UTC on April 25, 2015. The
epicenter was located at 28.147°N, 84.708°E, with the focal depth
of 15 km. In this paper, the coseismic ionospheric disturbances
were analyzed using Vertical Total Electron Content from Global
Navigation Satellite System (GNSS) observations obtained from 309
continuous tracking stations around the epicenter. The results show
that significant ionospheric disturbances occurred within 10 min after
the earthquake. The maximum anomaly reached 1.34 TECU; the maximum
duration was 10 min; the farthest anomaly was found beyond 3000 km
from the epicenter. The ionospheric response was attributed to two
modes: shock acoustic waves and Rayleigh wave. Within 500 km from
the epicenter, ionosphere anomaly was induced by both waves, with
average propagating speed of 0.61 and 1.62 km/s, respectively. With
increasing epicentral distance, the ionospheric disturbances caused
by acoustic waves gradually weakened, whereas Rayleigh waves induced
ionosphere disturbances reached up to 3000 km from the epicenter. The
propagation speed of Rayleigh waves gradually increased to 2.74
km/s while the distance from the epicenter to sub-ionospheric point
was over 1500 km. The occurrence of the disturbances appeared strong
directivity. The amplitudes of the disturbances were large to the south
of the epicenter. In contrast, to the northwest of the epicenter, few
disturbances were observed, and the amplitudes of these disturbances
were small. In general, the amplitude of the anomaly decreased with
increasing epicentral distance. However, the amplitude of the anomaly
increased at 1500-2500 km to the northeast of the epicenter.
Title: Upward-Pointing Cosmic-Ray-like Events Observed with ANITA
Authors: Romero-Wolf, A.; Anita Collaboration; Nam, J.; Hoover, S.;
Gorham, P. W.; Allison, P.; Batten, L.; Beatty, J. J.; Belov, K.;
Besson, D. Z.; Binns, W. R.; Cao, P.; Chen, C.; Chen, P.; Clem, J. M.;
Connolly, A.; Dailey, B.; Deaconu, C.; Cremonesi, L.; Dowkontt, P. F.;
Duvernois, M. A.; Field, R. C.; Goldstein, D.; Gordon, J.; Hast,
C.; Hebert, C. L.; Hill, B.; Hughes, K.; Hupe, R.; Israel, M. H.;
Javaid, A.; Kowalski, J.; Lam, J.; Ludwig, A.; Learned, J. G.; Liu,
T. C.; Link, J. T.; Lusczek, E.; Matsuno, S.; Mercurio, B. C.; Miki,
C.; Miocinovic, P.; Mottram, M.; Mulrey, K.; Naudet, C. J.; Ng, J.;
Nichol, R. J.; Novikov, A.; Palladino, K.; Prohira, S.; Rauch, B. F.;
Reil, K.; Roberts, J.; Rotter, B.; Russell, J.; Ruckman, L.; Saltzberg,
D.; Seckel, D.; Stafford, S.; Stockham, J.; Stockham, M.; Strutt, B.;
Tatem, K.; Varner, G. S.; Vieregg, A. G.; Walz, D.; Wissel, S. A.;
Wu, F.; Muñiz, J. A.; Carvalho, W., Jr.; Schoorlemmer, H.; Zas, E.
Bibcode: 2017ICRC...35..935R
Altcode: 2017PoS...301..935R
No abstract at ADS
Title: Design and Implementation of the TAROGE Experiment
Authors: Nam, J. W.; Chen, C. -C.; Chen, C. -H.; Chen, C. -W.; Chen,
P.; Chen, Y. -C.; Hsu, S. -Y.; Huang, J. -J.; Huang, M. -H. A.; Liu,
T. -C.; Řípa, J.; Shiao, Y. -S.; Wang, M. -Z.; Wang, S. -H.
Bibcode: 2017evgr.conf..126N
Altcode:
Taiwan astroparticle radiowave observatory for geo-synchrotron emissions
(TAROGE) is an antenna array on the high mountains of Taiwan's east
coast for the detection of ultra-high energy cosmic rays (UHECRs) in an
energy above 1018.5 eV. The antennas point toward the ocean
to detect radiowave signals emitted by the UHECR-induced air-shower
as a result of its interaction with the geomagnetic field. Looking
down from the coastal mountain, the effective area is enhanced
by collecting both direct-emission as well as the ocean-reflected
signals. This instrument also provides the capability of detecting
earth-skimming tau-neutrino through its subsequent tau-decay induced
shower. In order to prove the detection concept, initial two stations
were successfully built at 1000m elevation near Heping township, Taiwan,
in 2014-2015. Each station consists of 12 log-periodic dipole array
antennas for 110-300MHz. The stations have been operating smoothly
for radio survey and optimization of instrumental parameters. In
this report, we discuss the design of TAROGE, the performance of the
prototype station and the future prospect.
Title: Organic gas abundances in the plumes of Enceladus as seen by
Cassini UVIS
Authors: Kopparla, P.; Gao, P.; Shemansky, D. E.; Chen, P.; Newman,
S.; Ewald, S. P.; Yung, Y. L.
Bibcode: 2016AGUFM.P33A2123K
Altcode:
Enceladus' interior is thought to harbor a liquid ocean, possibly
in contact with a silicate core. Such a situation is very exciting
from the perspective of organic synthesis and habitability. Though
the posited subsurface ocean is beyond the reach of direct
observations, plume emissions can and have been used as probes of the
interior. Observations by Cassini UVIS show several absorption features
corresponding to hydrocarbon gases in the plume output. Using a simple
absorption/scattering model, we retrieve the abundances or upper limits
of these gases in the interior of Enceladus. The relative abundances of
various gases or their upper limits allow us to place constraints on
the processes that produce these gases in the interior and/or release
them into the plumes.
Title: Breaking of Magnetic Connectivity and Flare Initial Eruption
Authors: He, H.; Wang, H. N.; Yan, Y.; Chen, P. F.; Fang, C.
Bibcode: 2016AGUFMSH13C2307H
Altcode:
By quantitatively analyzing the 3-D coronal magnetic fields
(reconstructed using the nonlinear force-free field model) associated
with the X3.4-class solar flare event of AR 10930, a prominent
magnetic connectivity with strong negative α (force-free factor)
values and strong current density before the flare is revealed. This
magnetic connectivity extends along the main polarity inversion line
and is found to be totally broken after the flare. A cramped positive
α region appearing in the photosphere is identified as the cause
of the breaking of magnetic connectivity. The comparison with the
flare onset imaging observation exhibits that the breaking site of the
magnetic connectivity coincides with the location of the flare initial
eruption. A scenario for flare initial eruption is therefore proposed,
in which the Lorentz force acting on the isolated electric current at
the magnetic connectivity breaking site lifts the associated plasmas
and causes the initial ejection. The content of this presentation is
based on a published paper (He et al., 2014, JGR-Space Physics, 119,
3286-3315; also see arXiv:1605.00367).
Title: Can a Fast-Mode EUV Wave Generate a Stationary Front?
Authors: Chen, P. F.; Fang, C.; Chandra, R.; Srivastava, A. K.
Bibcode: 2016SoPh..291.3195C
Altcode: 2016arXiv160407982C; 2016SoPh..tmp...89C
The discovery of stationary "EIT waves" about 16 years ago posed a
big challenge to the then favorite fast-mode wave model for coronal
"EIT waves". It encouraged various non-wave models and played an
important role in convergence of the opposing viewpoints toward the
recent consensus that there are two types of EUV waves. However, it was
recently discovered that a stationary wave front can also be generated
when a fast-mode wave passes through a magnetic quasi-separatrix layer
(QSL). In this article, we perform a magnetohydrodynamic (MHD) numerical
simulation of the interaction between a fast-mode wave and a magnetic
QSL, and a stationary wave front is reproduced. The analysis of the
numerical results indicates that near the plasma beta ∼1 layer in
front of the magnetic QSL, part of the fast-mode wave is converted
to a slow-mode MHD wave, which is then trapped inside the magnetic
loops, forming a stationary wave front. Our results imply that we
have to be cautious in identifying the nature of a wave, since there
may be mode conversion during the propagation of the waves driven by
solar eruptions.
Title: Material Supply and Magnetic Configuration of an Active
Region Filament
Authors: Zou, P.; Fang, C.; Chen, P. F.; Yang, K.; Hao, Q.; Cao, Wenda
Bibcode: 2016ApJ...831..123Z
Altcode: 2017arXiv170102407Z
It is important to study the fine structures of solar filaments
with high-resolution observations, since it can help us understand
the magnetic and thermal structures of the filaments and their
dynamics. In this paper, we study a newly formed filament located
inside the active region NOAA 11762, which was observed by the 1.6 m
New Solar Telescope at Big Bear Solar Observatory from 16:40:19 UT to
17:07:58 UT on 2013 June 5. As revealed by the Hα filtergrams, cool
material is seen to be injected into the filament spine with a speed of
5-10 km s-1. At the source of the injection, brightenings
are identified in the chromosphere, which are accompanied by magnetic
cancellation in the photosphere, implying the importance of magnetic
reconnection in replenishing the filament with plasmas from the lower
atmosphere. Counter-streamings are detected near one endpoint of the
filament, with the plane-of-the-sky speed being 7-9 km s-1 in
the Hα red-wing filtergrams and 9-25 km s-1 in the blue-wing
filtergrams. The observations are indicative that this active region
filament is supported by a sheared arcade without magnetic dips, and
the counter-streamings are due to unidirectional flows with alternative
directions, rather than due to the longitudinal oscillations of filament
threads as in many other filaments.
Title: Investigating the Conditions of the Formation of a Type II
Radio Burst on 2014 January 8
Authors: Su, W.; Cheng, X.; Ding, M. D.; Chen, P. F.; Ning, Z. J.;
Ji, H. S.
Bibcode: 2016ApJ...830...70S
Altcode: 2016arXiv160905633S
It is believed that type II radio bursts are generated by shock
waves. In order to understand the generation conditions of type II
radio bursts, we analyze the physical parameters of a shock front. The
type II radio burst we selected was observed by the Siberian Solar
Radio Telescope (SSRT) and Learmonth radio station and was associated
with a limb coronal mass ejection (CME) occurring on 2014 January 8
observed by the Atmospheric Imaging Assembly on board the Solar Dynamics
Observatory. The evolution of the CME in the inner corona presents a
double-layered structure that propagates outward. We fit the outer layer
(OL) of the structure with a partial circle and divide it into seven
directions from -45° to 45° with an angular separation of 15°. We
measure the OL speed along the seven directions and find that the
speed in the direction of -15° with respect to the central direction
is the fastest. We use the differential emission measure method to
calculate the physical parameters at the OL at the moment when the type
II radio burst was initiated, including the temperature (T), emission
measure (EM), temperature ratio ({T}d/{T}{{u}}),
compression ratio (X), and Alfvén Mach number (M A). We
compare the quantities X and M A to those obtained from
band-splitting in the radio spectrum, and find that this type II radio
burst is generated at a small region of the OL that is located at the
sector in the 45° direction. The results suggest that the generation
of type II radio bursts (shocks) requires larger values of X and M
A rather than simply a higher speed of the disturbance.
Title: Understanding the Physical Nature of Coronal "EIT Waves"
Authors: Long, D. M.; Bloomfield, D. S.; Chen, P. -F.; Downs,
C.; Gallagher, P. T.; Kwon, R. -Y.; Vanninathan, K.; Veronig, A.;
Vourlidas, A.; Vrsnak, B.; Warmuth, A.; Zic, T.
Bibcode: 2016usc..confE..24L
Altcode:
For almost 20 years the physical nature of globally-propagating waves
in the solar corona (commonly called "EIT waves") has been controversial
and subject to debate. Additional theories have been proposed throughout
the years to explain observations that did not fit with the originally
proposed fast-mode wave interpretation. However, the incompatibility
of observations made using the Extreme-ultraviolet Imaging Telescope
(EIT) on the Solar and Heliospheric Observatory with the fast-mode
wave interpretation have been challenged by differing viewpoints
from the Solar Terrestrial Relations Observatory spacecraft and higher
spatial/temporal resolution data from the Solar Dynamics Observatory. In
this paper, we reexamine the theories proposed to explain "EIT waves"
to identify measurable properties and behaviours that can be compared
to current and future observations. Most of us conclude that "EIT
waves" are best described as fast-mode large-amplitude waves/shocks,
which are initially driven by the impulsive expansion of an erupting
coronal mass ejection in the low corona.
Title: High-resolution Observations of a Large Fan-shaped Surge
Authors: Li, Zhen; Fang, Cheng; Guo, Yang; Chen, P. F.; Zou, Peng;
Cao, Wenda
Bibcode: 2016ApJ...826..217L
Altcode:
We present high-resolution observations of a large fan-shaped
surge, which was observed on 2013 June 5 with the current largest
solar telescope, the 1.6 m New Solar Telescope (NST), at the
Big Bear Solar Observatory. The observations are made at TiO,
Hα, and 10830 Å wavebands with a spatial resolution better
than 0\buildrel{\prime\prime}\over{.} 1 and a full-run cadence of
∼30 s. The fan-shaped surge consists of many small-scale threads
with a typical width of 100 km and a length of up to 200 Mm at the
maximum. The threads come from material ejections, which start with a
velocity of several km s-1, and then accelerate up to 60-80
km s-1 over six to seven minutes with an acceleration of
up to 0.2-0.3 km s-2. The threads can be observed in the
Hα band and in SDO/AIA 171 Å images as absorbed objects, implying
that they are cool material ejections. The surge is ejected along open
magnetic field lines in the extrapolated non-linear force-free field,
which might actually be a part of a large-scale magnetic loop stretching
back to the solar surface. After 10-20 minutes, the ejections gradually
decay and the surge eventually vanishes. The total lifetime is about 35
minutes. The Hα brightening at the root of the fan-shaped surge implies
that there is heating in the chromosphere, which could be produced
by low-atmosphere interchange magnetic reconnection. Our observation
provides evidence of the reconnection model for the fan-shaped surges,
which was proposed by Jiang et al.
Title: Marine Targets Detection in Pol-SAR Data
Authors: Chen, Peng; Yang, Jingsong
Bibcode: 2016ESASP.739E..23C
Altcode:
In this poster, we present a new method of marine target detection
in Pol-SAR data. One band SAR image, like HH, VV or VH, can be
used to find marine target using a Contant False Alarm Ratio (CFAR)
algorithm. But some false detection may happen, as the sidelobe of
antenna, Azimuth ambiguity, strong speckle noise and so on in the
single band SAR image. Pol-SAR image can get more information of
targets. After decomposition and false color composite, the sidelobe
of antenna and Azimuth ambiguity could be deleted. So, the method
presented include three steps, decomposion, false color composite and
supervised classification. The result of Radarsat-2 SAR image test
indicates a good accuracy. The detection results are compared with
Automatic Indentify Sistem (AIS) data, the accuracy of right detection
is above 95% and false detection ratio is below 5%.
Title: Characteristics of Four Upward-Pointing Cosmic-Ray-like Events
Observed with ANITA
Authors: Gorham, P. W.; Nam, J.; Romero-Wolf, A.; Hoover, S.;
Allison, P.; Banerjee, O.; Beatty, J. J.; Belov, K.; Besson, D. Z.;
Binns, W. R.; Bugaev, V.; Cao, P.; Chen, C.; Chen, P.; Clem, J. M.;
Connolly, A.; Dailey, B.; Deaconu, C.; Cremonesi, L.; Dowkontt, P. F.;
Duvernois, M. A.; Field, R. C.; Fox, B. D.; Goldstein, D.; Gordon, J.;
Hast, C.; Hebert, C. L.; Hill, B.; Hughes, K.; Hupe, R.; Israel, M. H.;
Javaid, A.; Kowalski, J.; Lam, J.; Learned, J. G.; Liewer, K. M.; Liu,
T. C.; Link, J. T.; Lusczek, E.; Matsuno, S.; Mercurio, B. C.; Miki,
C.; Miočinović, P.; Mottram, M.; Mulrey, K.; Naudet, C. J.; Ng,
J.; Nichol, R. J.; Palladino, K.; Rauch, B. F.; Reil, K.; Roberts,
J.; Rosen, M.; Rotter, B.; Russell, J.; Ruckman, L.; Saltzberg, D.;
Seckel, D.; Schoorlemmer, H.; Stafford, S.; Stockham, J.; Stockham,
M.; Strutt, B.; Tatem, K.; Varner, G. S.; Vieregg, A. G.; Walz, D.;
Wissel, S. A.; Wu, F.; Anita Collaboration
Bibcode: 2016PhRvL.117g1101G
Altcode: 2016arXiv160305218G
We report on four radio-detected cosmic-ray (CR) or CR-like events
observed with the Antarctic Impulsive Transient Antenna (ANITA),
a NASA-sponsored long-duration balloon payload. Two of the four were
previously identified as stratospheric CR air showers during the ANITA-I
flight. A third stratospheric CR was detected during the ANITA-II
flight. Here, we report on characteristics of these three unusual CR
events, which develop nearly horizontally, 20-30 km above the surface
of Earth. In addition, we report on a fourth steeply upward-pointing
ANITA-I CR-like radio event which has characteristics consistent with
a primary that emerged from the surface of the ice. This suggests a
possible τ -lepton decay as the origin of this event, but such an
interpretation would require significant suppression of the standard
model τ -neutrino cross section.
Title: ASAS-SN Transient Discovery Report for 2016-08-25
Authors: Chen, P.; Dong, S.
Bibcode: 2016TNSTR.591....1C
Altcode:
No abstract at ADS
Title: Design and implementation of the TAROGE experiment
Authors: Nam, J. W.; Chen, C. -C.; Chen, C. -H.; Chen, C. -W.; Chen,
P.; Chen, Y. -C.; Hsu, S. -Y.; Huang, J. -J.; Huang, M. -H. A.; Liu,
T. -C.; Řípa, J.; Shiao, Y. -S.; Wang, M. -Z.; Wang, S. -H.
Bibcode: 2016IJMPD..2545013N
Altcode:
Taiwan astroparticle radiowave observatory for geo-synchrotron emissions
(TAROGE) is an antenna array on the high mountains of Taiwan’s east
coast for the detection of ultra-high energy cosmic rays (UHECRs)
in an energy above 1018.5 eV. The antennas point toward the ocean to
detect radiowave signals emitted by the UHECR-induced air-shower as a
result of its interaction with the geomagnetic field. Looking down from
the coastal mountain, the effective area is enhanced by collecting both
direct-emission as well as the ocean-reflected signals. This instrument
also provides the capability of detecting earth-skimming tau-neutrino
through its subsequent tau-decay induced shower. In order to prove
the detection concept, initial two stations were successfully built
at 1000 m elevation near Heping township, Taiwan, in 2014-2015. Each
station consists of 12 log-periodic dipole array antennas for 110-300
MHz. The stations have been operating smoothly for radio survey and
optimization of instrumental parameters. In this report, we discuss
the design of TAROGE, the performance of the prototype station and
the future prospect.
Title: Peculiar Stationary EUV Wave Fronts in the Eruption on 2011
May 11
Authors: Chandra, R.; Chen, P. F.; Fulara, A.; Srivastava, A. K.;
Uddin, W.
Bibcode: 2016ApJ...822..106C
Altcode: 2016arXiv160208693C
We present and interpret the observations of extreme ultraviolet (EUV)
waves associated with a filament eruption on 2011 May 11. The filament
eruption also produces a small B-class two ribbon flare and a coronal
mass ejection. The event is observed by the Solar Dynamic Observatory
with high spatio-temporal resolution data recorded by the Atmospheric
Imaging Assembly. As the filament erupts, we observe two types of EUV
waves (slow and fast) propagating outwards. The faster EUV wave has
a propagation velocity of ∼500 km s-1 and the slower EUV
wave has an initial velocity of ∼120 km s-1. We report,
for the first time, that not only does the slower EUV wave stop at
a magnetic separatrix to form bright stationary fronts, but also
the faster EUV wave transits a magnetic separatrix, leaving another
stationary EUV front behind.
Title: VizieR Online Data Catalog: HCO+ and HCN obs. toward Planck
Galactic Cold Clumps (Yuan+, 2016)
Authors: Yuan, J.; Wu, Y.; Liu, T.; Zhang, T.; Li, J. Z.; Liu, H. -L.;
Meng, F.; Chen, P.; Hu, R.; Wang, K.
Bibcode: 2016yCat..18200037Y
Altcode:
More than 600 Planck cold clumps have been mapped in the J=1-0
transitions of 12CO, 13CO, and C18O. A
22'x22' region for each clump was mapped with a spatial resolution of
about 52". Details about the mapping observations are provided by Liu
et al. (2012, J/ApJS/202/4) and Meng et al. (2013, J/ApJS/209/37). Single-pointing observations of the CO-selected cores in HCO+
J=1-0 (89.189GHz) and HCN J=1-0 (88.632GHz) were carried out using
the 13.7m telescope of the Purple Mountain Observatory (PMO) with
the position-switch mode from 2013 June to July and from 2014 May to
June. (2 data files).
Title: Performance of two Askaryan Radio Array stations and first
results in the search for ultrahigh energy neutrinos
Authors: Allison, P.; Bard, R.; Beatty, J. J.; Besson, D. Z.; Bora, C.;
Chen, C. -C.; Chen, C. -H.; Chen, P.; Christenson, A.; Connolly, A.;
Davies, J.; Duvernois, M.; Fox, B.; Gaior, R.; Gorham, P. W.; Hanson,
K.; Haugen, J.; Hill, B.; Hoffman, K. D.; Hong, E.; Hsu, S. -Y.;
Hu, L.; Huang, J. -J.; Huang, M. -H. A.; Ishihara, A.; Karle, A.;
Kelley, J. L.; Kennedy, D.; Kravchenko, I.; Kuwabara, T.; Landsman,
H.; Laundrie, A.; Li, C. -J.; Liu, T. C.; Lu, M. -Y.; Macchiarulo,
L.; Mase, K.; Meures, T.; Meyhandan, R.; Miki, C.; Morse, R.; Nam,
J.; Nichol, R. J.; Nir, G.; Novikov, A.; O'Murchadha, A.; Pfendner,
C.; Ratzlaff, K.; Relich, M.; Richman, M.; Ritter, L.; Rotter, B.;
Sandstrom, P.; Schellin, P.; Shultz, A.; Seckel, D.; Shiao, Y. -S.;
Stockham, J.; Stockham, M.; Touart, J.; Varner, G. S.; Wang, M. -Z.;
Wang, S. -H.; Yang, Y.; Yoshida, S.; Young, R.; ARA Collaboration
Bibcode: 2016PhRvD..93h2003A
Altcode: 2015arXiv150708991A
Ultrahigh energy neutrinos are interesting messenger particles since,
if detected, they can transmit exclusive information about ultrahigh
energy processes in the Universe. These particles, with energies above
1016 eV , interact very rarely. Therefore, detectors that
instrument several gigatons of matter are needed to discover them. The
ARA detector is currently being constructed at the South Pole. It is
designed to use the Askaryan effect, the emission of radio waves from
neutrino-induced cascades in the South Pole ice, to detect neutrino
interactions at very high energies. With antennas distributed among
37 widely separated stations in the ice, such interactions can be
observed in a volume of several hundred cubic kilometers. Currently
three deep ARA stations are deployed in the ice, of which two have
been taking data since the beginning of 2013. In this article, the
ARA detector "as built" and calibrations are described. Data reduction
methods used to distinguish the rare radio signals from overwhelming
backgrounds of thermal and anthropogenic origin are presented. Using
data from only two stations over a short exposure time of 10 months,
a neutrino flux limit of 1.5 ×10-6 GeV /cm2/s
/sr is calculated for a particle energy of 1018 eV , which
offers promise for the full ARA detector.
Title: Accelerator Measurements of Magnetically Induced Radio Emission
from Particle Cascades with Applications to Cosmic-Ray Air Showers
Authors: Belov, K.; Mulrey, K.; Romero-Wolf, A.; Wissel, S. A.; Zilles,
A.; Bechtol, K.; Borch, K.; Chen, P.; Clem, J.; Gorham, P. W.; Hast,
C.; Huege, T.; Hyneman, R.; Jobe, K.; Kuwatani, K.; Lam, J.; Liu,
T. C.; Nam, J.; Naudet, C.; Nichol, R. J.; Rauch, B. F.; Rotter, B.;
Saltzberg, D.; Schoorlemmer, H.; Seckel, D.; Strutt, B.; Vieregg,
A. G.; Williams, C.; T-510 Collaboration
Bibcode: 2016PhRvL.116n1103B
Altcode: 2015arXiv150707296B
For 50 years, cosmic-ray air showers have been detected by their radio
emission. We present the first laboratory measurements that validate
electrodynamics simulations used in air shower modeling. An experiment
at SLAC provides a beam test of radio-frequency (rf) radiation from
charged particle cascades in the presence of a magnetic field, a model
system of a cosmic-ray air shower. This experiment provides a suite
of controlled laboratory measurements to compare to particle-level
simulations of rf emission, which are relied upon in ultrahigh-energy
cosmic-ray air shower detection. We compare simulations to data
for intensity, linearity with magnetic field, angular distribution,
polarization, and spectral content. In particular, we confirm modern
predictions that the magnetically induced emission in a dielectric
forms a cone that peaks at the Cherenkov angle and show that the
simulations reproduce the data within systematic uncertainties.
Title: Energy and flux measurements of ultra-high energy cosmic rays
observed during the first ANITA flight
Authors: Schoorlemmer, H.; Belov, K.; Romero-Wolf, A.;
García-Fernández, D.; Bugaev, V.; Wissel, S. A.; Allison, P.;
Alvarez-Muñiz, J.; Barwick, S. W.; Beatty, J. J.; Besson, D. Z.;
Binns, W. R.; Carvalho, W. R., Jr.; Chen, C.; Chen, P.; Clem,
J. M.; Connolly, A.; Dowkontt, P. F.; DuVernois, M. A.; Field,
R. C.; Goldstein, D.; Gorham, P. W.; Hast, C.; Huege, T.; Heber,
C. L.; Hoover, S.; Israel, M. H.; Javaid, A.; Kowalski, J.; Lam, J.;
Learned, J. G.; Link, J. T.; Lusczek, E.; Matsuno, S.; Mercurio, B. C.;
Miki, C.; Miočinović, P.; Mulrey, K.; Nam, J.; Naudet, C. J.; Ng,
J.; Nichol, R. J.; Palladino, K.; Rauch, B. F.; Roberts, J.; Reil,
K.; Rotter, B.; Rosen, M.; Ruckman, L.; Saltzberg, D.; Seckel, D.;
Urdaneta, D.; Varner, G. S.; Vieregg, A. G.; Walz, D.; Wu, F.; Zas, E.
Bibcode: 2016APh....77...32S
Altcode: 2015arXiv150605396S
The first flight of the Antarctic Impulsive Transient Antenna (ANITA)
experiment recorded 16 radio signals that were emitted by cosmic-ray
induced air showers. The dominant contribution to the radiation comes
from the deflection of positrons and electrons in the geomagnetic field,
which is beamed in the direction of motion of the air shower. For
14 of these events, this radiation is reflected from the ice and
subsequently detected by the ANITA experiment at a flight altitude of
∼36 km. In this paper, we estimate the energy of the 14 individual
events and find that the mean energy of the cosmic-ray sample is 2.9
× 1018 eV, which is significantly lower than the previous
estimate. By simulating the ANITA flight, we calculate its exposure
for ultra-high energy cosmic rays. We estimate for the first time
the cosmic-ray flux derived only from radio observations and find
agreement with measurements performed at other observatories. In
addition, we find that the ANITA data set is consistent with Monte
Carlo simulations for the total number of observed events and with
the properties of those events.
Title: ASAS-SN Transient Discovery Report for 2016-03-05
Authors: Brown, J. S.; Dong, S.; Holoien, T. W. S.; Stanek, K. Z.;
Kochanek, C. S.; Godoy-rivera, D.; Basu, U.; Shappee, B. J.; Prieto,
J. L.; Bersier, D.; Chen, P.; Brimacombe, J.
Bibcode: 2016TNSTR.184....1B
Altcode:
No abstract at ADS
Title: ASAS-SN Transient Discovery Report for 2016-02-06
Authors: Brown, J. S.; Dong, S.; Stanek, K. Z.; Holoien, T. W. S.;
Kochanek, C. S.; Godoy-rivera, D.; Basu, U.; Shappee, B. J.; Prieto,
J. L.; Bersier, D.; Chen, P.; Brimacombe, J.; Fernandez, J. M.;
Kiyota, S.
Bibcode: 2016TNSTR..85....1B
Altcode:
No abstract at ADS
Title: ASAS-SN Transient Discovery Report for 2016-02-12
Authors: Brimacombe, J.; Brown, J. S.; Holoien, T. W. S.; Stanek,
K. Z.; Kochanek, C. S.; Godoy-rivera, D.; Basu, U.; Shappee, B. J.;
Prieto, J. L.; Bersier, D.; Dong, S.; Chen, P.; Bock, G.; Cruz, I.;
Kiyota, S.; Masi, G.
Bibcode: 2016TNSTR.106....1B
Altcode:
No abstract at ADS
Title: ASAS-SN Transient Discovery Report for 2016-02-03
Authors: Fernandez, J. M.; Kiyota, S.; Brown, J. S.; Stanek, K. Z.;
Holoien, T. W. S.; Kochanek, C. S.; Godoy-rivera, D.; Basu, U.;
Shappee, B. J.; Prieto, J. L.; Bersier, D.; Dong, S.; Chen, P.;
Brimacombe, J.; Koff, R. A.; Masi, G.
Bibcode: 2016TNSTR..74....1F
Altcode:
No abstract at ADS
Title: Global Coronal Waves
Authors: Chen, P. F.
Bibcode: 2016GMS...216..381C
Altcode: 2016arXiv160407991C; 2016GMS...216..379C
After the Solar and Heliospheric Observatory (SOHO) was launched in
1996, the aboard Extreme Ultraviolet Imaging Telescope (EIT) observed
a global coronal wave phenomenon, which was initially named ``EIT
wave" after the telescope. The bright fronts are immediately followed
by expanding dimmings. It has been shown that the brightenings and
dimmings are mainly due to plasma density increase and depletion,
respectively. Such a spectacular phenomenon sparked long-lasting
interest and debates. The debates were concentrated on two topics,
one is about the driving source, and the other is about the nature of
this wavelike phenomenon. The controversies are most probably because
there may exist two types of large-scale coronal waves that were not
well resolved before the Solar Dynamics Observatory (SDO) was launched:
one is a piston-driven shock wave straddling over the erupting coronal
mass ejection (CME), and the other is an apparently propagating front,
which may correspond to the CME frontal loop. Such a two-wave paradigm
was proposed more than 13 years ago, and now is being recognized by more
and more colleagues. In this paper, we review how various controversies
can be resolved in the two-wave framework and how important it is to
have two different names for the two types of coronal waves.
Title: ASAS-SN Transient Discovery Report for 2016-02-08
Authors: Brimacombe, J.; Kiyota, S.; Brown, J. S.; Holoien, T. W. S.;
Stanek, K. Z.; Kochanek, C. S.; Godoy-rivera, D.; Basu, U.; Shappee,
B. J.; Prieto, J. L.; Bersier, D.; Dong, S.; Chen, P.; Bock, G.;
Cruz, I.; Fernandez, J. M.
Bibcode: 2016TNSTR..93....1B
Altcode:
No abstract at ADS
Title: ASAS-SN Transient Discovery Report for 2016-01-17
Authors: Masi, G.; Brown, J. S.; Stanek, K. Z.; Holoien, T. W. S.;
Kochanek, C. S.; Godoy-rivera, D.; Basu, U.; Shappee, B. J.; Prieto,
J. L.; Bersier, D.; Dong, S.; Chen, P.; Brimacombe, J.; Bock, G.;
Kiyota, S.
Bibcode: 2016TNSTR..26....1M
Altcode:
No abstract at ADS
Title: Spectroscopic classification of PSNJ 09195286-6854419
Authors: Galbany, L.; Gonzalez-Gaitan, S.; Dong, S.; Chen, P.;
Hamuy, M.
Bibcode: 2016ATel.8541....1G
Altcode:
We report optical spectroscopy of the supernova candidate PSNJ
09195286-6854419. The spectrum (390-990nm) was obtained on UT 2016
Jan. 12.3 with the LDSS3 mounted to the Clay telescope at Las Campanas
Observatory.
Title: ASAS-SN Transient Discovery Report for 2016-01-20
Authors: Masi, G.; Bersier, D.; Shappee, B. J.; Brown, J. S.; Stanek,
K. Z.; Holoien, T. W. S.; Kochanek, C. S.; Godoy-rivera, D.; Basu, U.;
Prieto, J. L.; Dong, S.; Chen, P.; Brimacombe, J.; Bock, G.; Kiyota, S.
Bibcode: 2016TNSTR..37....1M
Altcode:
No abstract at ADS
Title: ASAS-SN Transient Discovery Report for 2016-01-26
Authors: Masi, G.; Brown, J. S.; Holoien, T. W. S.; Stanek, K. Z.;
Kochanek, C. S.; Godoy-rivera, D.; Basu, U.; Shappee, B. J.; Prieto,
J. L.; Bersier, D.; Dong, S.; Chen, P.; Brimacombe, J.; Bock, G.;
Cruz, I.; Kiyota, S.
Bibcode: 2016TNSTR..52....1M
Altcode:
No abstract at ADS
Title: ASAS-SN Transient Discovery Report for 2016-01-13
Authors: Brimacombe, J.; Koff, R. A.; Bersier, D.; Prieto, J. L.;
Brown, J. S.; Holoien, T. W. S.; Stanek, K. Z.; Kochanek, C. S.;
Godoy-rivera, D.; Basu, U.; Shappee, B. J.; Dong, S.; Chen, P.;
Conseil, E.; Kiyota, S.; Krannich, G.
Bibcode: 2016TNSTR..17....1B
Altcode:
No abstract at ADS
Title: ASAS-SN Transient Discovery Report for 2016-01-15
Authors: Kiyota, S.; Brown, J. S.; Stanek, K. Z.; Holoien, T. W. S.;
Kochanek, C. S.; Godoy-rivera, D.; Basu, U.; Shappee, B. J.; Prieto,
J. L.; Bersier, D.; Dong, S.; Chen, P.; Brimacombe, J.; Bock, G.;
Koff, R. A.
Bibcode: 2016TNSTR..23....1K
Altcode:
No abstract at ADS
Title: ASAS-SN Transient Discovery Report for 2016-01-29
Authors: Kiyota, S.; Brown, J. S.; Holoien, T. W. S.; Stanek, K. Z.;
Kochanek, C. S.; Godoy-rivera, D.; Basu, U.; Shappee, B. J.; Prieto,
J. L.; Bersier, D.; Dong, S.; Chen, P.; Brimacombe, J.; Bock, G.;
Koff, R. A.; Masi, G.
Bibcode: 2016TNSTR..64....1K
Altcode:
No abstract at ADS
Title: ASAS-SN Transient Discovery Report for 2016-01-20
Authors: Stanek; Bock; Shappee; Brown; Holoien; Kochanek; Godoy-rivera;
Basu; Prieto; Bersier; Dong; Chen; Brimacombe
Bibcode: 2016TNSTR..38....1S
Altcode:
No abstract at ADS
Title: ASAS-SN Transient Discovery Report for 2016-01-10
Authors: Dong, S.; Brimacombe, J.; Stanek, K. Z.; Brown, J. S.;
Holoien, T. W. S.; Kochanek, C. S.; Godoy-rivera, D.; Basu, U.;
Shappee, B. J.; Prieto, J. L.; Bersier, D.; Chen, P.
Bibcode: 2016TNSTR..10....1D
Altcode:
No abstract at ADS
Title: ASAS-SN Transient Discovery Report for 2016-01-01
Authors: Conseil, E.; Dong, S.; Brown, J. S.; Stanek, K. Z.; Holoien,
T. W. S.; Kochanek, C. S.; Godoy-rivera, D.; Basu, U.; Shappee, B. J.;
Prieto, J. L.; Bersier, D.; Chen, P.; Brimacombe, J.
Bibcode: 2016TNSTR...1....1C
Altcode:
No abstract at ADS
Title: ASAS-SN Transient Discovery Report for 2016-01-12
Authors: Stanek; Brown; Holoien; Kochanek; Godoy-Rivera; Basu; Shappee;
Prieto; Bersier; Dong; Chen; Brimacombe
Bibcode: 2016TNSTR..15....1S
Altcode:
No abstract at ADS
Title: ASAS-SN Transient Discovery Report for 2016-01-03
Authors: Stanek; Brown; Holoien; Kochanek; Godoy-rivera; Basu; Shappee;
Prieto; Bersier; Dong; Chen; Brimacombe
Bibcode: 2016TNSTR...3....1S
Altcode:
No abstract at ADS
Title: Demonstration of a near-IR line-referenced electro-optical
laser frequency comb for precision radial velocity measurements
in astronomy
Authors: Yi, X.; Vahala, K.; Li, J.; Diddams, S.; Ycas, G.; Plavchan,
P.; Leifer, S.; Sandhu, J.; Vasisht, G.; Chen, P.; Gao, P.; Gagne, J.;
Furlan, E.; Bottom, M.; Martin, E. C.; Fitzgerald, M. P.; Doppmann,
G.; Beichman, C.
Bibcode: 2016NatCo...710436Y
Altcode: 2015arXiv150102509Y
An important technique for discovering and characterizing planets beyond
our solar system relies upon measurement of weak Doppler shifts in the
spectra of host stars induced by the influence of orbiting planets. A
recent advance has been the introduction of optical frequency combs as
frequency references. Frequency combs produce a series of equally spaced
reference frequencies and they offer extreme accuracy and spectral
grasp that can potentially revolutionize exoplanet detection. Here we
demonstrate a laser frequency comb using an alternate comb generation
method based on electro-optical modulation, with the comb centre
wavelength stabilized to a molecular or atomic reference. In contrast to
mode-locked combs, the line spacing is readily resolvable using typical
astronomical grating spectrographs. Built using commercial off-the-shelf
components, the instrument is relatively simple and reliable. Proof of
concept experiments operated at near-infrared wavelengths were carried
out at the NASA Infrared Telescope Facility and the Keck-II telescope.
Title: Can we determine the filament chirality by the filament
footpoint location or the barb-bearing?
Authors: Hao, Qi; Guo, Yang; Fang, Cheng; Chen, Peng-Fei; Cao, Wen-Da
Bibcode: 2016RAA....16....1H
Altcode: 2015arXiv150608490H; 2016RAA....16a...1H
We attempt to propose a method for automatically detecting the solar
filament chirality and barb bearing. We first introduce the concept of
an unweighted undirected graph and adopt the Dijkstra shortest path
algorithm to recognize the filament spine. Then, we use the polarity
inversion line (PIL) shift method for measuring the polarities on both
sides of the filament, and employ the connected components labeling
method to identify the barbs and calculate the angle between each
barb and the spine to determine the bearing of the barbs, i.e.,
left or right. We test the automatic detection method with Hα
filtergrams from the Big Bear Solar Observatory (BBSO) Hα archive
and magnetograms observed with the Helioseismic and Magnetic Imager
(HMI) on board the Solar Dynamics Observatory (SDO). Four filaments
are automatically detected and illustrated to show the results. The
barbs in different parts of a filament may have opposite bearings. The
filaments in the southern hemisphere (northern hemisphere) mainly
have left-bearing (right-bearing) barbs and positive (negative)
magnetic helicity, respectively. The tested results demonstrate that
our method is efficient and effective in detecting the bearing of
filament barbs. It is demonstrated that the conventionally believed
one-to-one correspondence between filament chirality and barb bearing
is not valid. The correct detection of the filament axis chirality
should be done by combining both imaging morphology and magnetic
field observations.
Title: ASAS-SN Transient Discovery Report for 2016-01-02
Authors: Stanek; Brown; Holoien; Kochanek; Godoy-rivera; Basu; Shappee;
Prieto; Bersier; Dong; Chen; Brimacombe
Bibcode: 2016TNSTR...2....1S
Altcode:
No abstract at ADS
Title: Is Flux Rope a Necessary Condition for the Progenitor of
Coronal Mass Ejections?
Authors: Ouyang, Y.; Yang, K.; Chen, P. F.
Bibcode: 2015ApJ...815...72O
Altcode: 2015arXiv151101605O
A magnetic flux rope structure is believed to exist in most coronal
mass ejections (CMEs). However, it has been long debated whether the
flux rope exists before eruption or if it is formed during eruption
via magnetic reconnection. The controversy has continued because of our
lack of routine measurements of the magnetic field in the pre-eruption
structure, such as solar filaments. However, recently an indirect method
was proposed to infer the magnetic field configuration based on the
sign of helicity and the bearing direction of the filament barbs. In
this paper, we apply this method to two erupting filament events, one
on 2014 September 2 and the other on 2011 March 7, and find that the
first filament is supported by a magnetic flux rope and the second
filament is supported by a sheared arcade, i.e., the first one is
an inverse-polarity filament and the second one is a normal-polarity
filament. With the identification of the magnetic configurations in
these two filaments, we stress that a flux rope is not a necessary
condition for the pre-CME structure.
Title: Statistical Analysis of Filament Features Based on the Hα
Solar Images from 1988 to 2013 by Computer Automated Detection Method
Authors: Hao, Q.; Fang, C.; Cao, W.; Chen, P. F.
Bibcode: 2015ApJS..221...33H
Altcode: 2015arXiv151104692H
We improve our filament automated detection method which was proposed
in our previous works. It is then applied to process the full disk
Hα data mainly obtained by the Big Bear Solar Observatory from 1988
to 2013, spanning nearly three solar cycles. The butterfly diagrams
of the filaments, showing the information of the filament area,
spine length, tilt angle, and the barb number, are obtained. The
variations of these features with the calendar year and the latitude
band are analyzed. The drift velocities of the filaments in different
latitude bands are calculated and studied. We also investigate the
north-south (N-S) asymmetries of the filament numbers in total and in
each subclass classified according to the filament area, spine length,
and tilt angle. The latitudinal distribution of the filament number
is found to be bimodal. About 80% of all the filaments have tilt
angles within [0°, 60°]. For the filaments within latitudes lower
(higher) than 50°, the northeast (northwest) direction is dominant
in the northern hemisphere and the southeast (southwest) direction is
dominant in the southern hemisphere. The latitudinal migrations of the
filaments experience three stages with declining drift velocities in
each of solar cycles 22 and 23, and it seems that the drift velocity
is faster in shorter solar cycles. Most filaments in latitudes lower
(higher) than 50° migrate toward the equator (polar region). The
N-S asymmetry indices indicate that the southern hemisphere is the
dominant hemisphere in solar cycle 22 and the northern hemisphere is
the dominant one in solar cycle 23.
Title: Fine Magnetic Structure and Origin of Counter-streaming Mass
Flows in a Quiescent Solar Prominence
Authors: Shen, Yuandeng; Liu, Yu; Liu, Ying D.; Chen, P. F.; Su,
Jiangtao; Xu, Zhi; Liu, Zhong
Bibcode: 2015ApJ...814L..17S
Altcode: 2015arXiv151102489S
We present high-resolution observations of a quiescent solar
prominence that consists of a vertical and a horizontal foot encircled
by an overlying spine and has ubiquitous counter-streaming mass
flows. While the horizontal foot and the spine were connected to the
solar surface, the vertical foot was suspended above the solar surface
and was supported by a semicircular bubble structure. The bubble first
collapsed, then reformed at a similar height, and finally started to
oscillate for a long time. We find that the collapse and oscillation of
the bubble boundary were tightly associated with a flare-like feature
located at the bottom of the bubble. Based on the observational results,
we propose that the prominence should be composed of an overlying
horizontal spine encircling a low-lying horizontal and vertical foot,
in which the horizontal foot consists of shorter field lines running
partially along the spine and has ends connected to the solar surface,
while the vertical foot consists of piling-up dips due to the sagging
of the spine fields and is supported by a bipolar magnetic system formed
by parasitic polarities (i.e., the bubble). The upflows in the vertical
foot were possibly caused by the magnetic reconnection at the separator
between the bubble and the overlying dips, which intruded into the
persistent downflow field and formed the picture of counter-streaming
mass flows. In addition, the counter-streaming flows in the horizontal
foot were possibly caused by the imbalanced pressure at the both ends.
Title: Black hole remnants and the information loss paradox
Authors: Chen, P.; Ong, Y. C.; Yeom, D. -h.
Bibcode: 2015PhR...603....1C
Altcode: 2014arXiv1412.8366C
Forty years after the discovery of Hawking radiation, its exact nature
remains elusive. If Hawking radiation does not carry any information
out from the ever shrinking black hole, it seems that unitarity is
violated once the black hole completely evaporates. On the other hand,
attempts to recover information via quantum entanglement lead to
the firewall controversy. Amid the confusions, the possibility that
black hole evaporation stops with a "remnant" has remained unpopular
and is often dismissed due to some "undesired properties" of such an
object. Nevertheless, as in any scientific debate, the pros and cons
of any proposal must be carefully scrutinized. We fill in the void of
the literature by providing a timely review of various types of black
hole remnants, and provide some new thoughts regarding the challenges
that black hole remnants face in the context of the information loss
paradox and its latest incarnation, namely the firewall controversy. The
importance of understanding the role of curvature singularity is also
emphasized, after all there remains a possibility that the singularity
cannot be cured even by quantum gravity. In this context a black
hole remnant conveniently serves as a cosmic censor. We conclude
that a remnant remains a possible end state of Hawking evaporation,
and if it contains large interior geometry, may help to ameliorate
the information loss paradox and the firewall controversy. We hope
that this will raise some interests in the community to investigate
remnants more critically but also more thoroughly.
Title: First constraints on the ultra-high energy neutrino flux from
a prototype station of the Askaryan Radio Array
Authors: Allison, P.; Auffenberg, J.; Bard, R.; Beatty, J. J.;
Besson, D. Z.; Bora, C.; Chen, C. -C.; Chen, P.; Connolly, A.; Davies,
J. P.; DuVernois, M. A.; Fox, B.; Gorham, P. W.; Hanson, K.; Hill,
B.; Hoffman, K. D.; Hong, E.; Hu, L. -C.; Ishihara, A.; Karle, A.;
Kelley, J.; Kravchenko, I.; Landsman, H.; Laundrie, A.; Li, C. -J.;
Liu, T.; Lu, M. -Y.; Maunu, R.; Mase, K.; Meures, T.; Miki, C.;
Nam, J.; Nichol, R. J.; Nir, G.; O'Murchadha, A.; Pfendner, C. G.;
Ratzlaff, K.; Richman, M.; Rotter, B.; Sandstrom, P.; Seckel, D.;
Shultz, A.; Stockham, J.; Stockham, M.; Sullivan, M.; Touart, J.;
Tu, H. -Y.; Varner, G. S.; Yoshida, S.; Young, R.
Bibcode: 2015APh....70...62A
Altcode: 2014arXiv1404.5285A
The Askaryan Radio Array (ARA) is an ultra-high energy
(>1017 eV) cosmic neutrino detector in phased construction
near the south pole. ARA searches for radio Cherenkov emission from
particle cascades induced by neutrino interactions in the ice using
radio frequency antennas (∼ 150 - 800 MHz) deployed at a design
depth of 200 m in the Antarctic ice. A prototype ARA Testbed station
was deployed at ∼ 30 m depth in the 2010-2011 season and the first
three full ARA stations were deployed in the 2011-2012 and 2012-2013
seasons. We present the first neutrino search with ARA using data taken
in 2011 and 2012 with the ARA Testbed and the resulting constraints
on the neutrino flux from 1017 -1021 eV.
Title: MHD Seismology of a loop-like filament tube by observed
kink waves
Authors: Pant, Vaibhav; Srivastava, Abhishek K.; Banerjee, Dipankar;
Goossens, Marcel; Chen, Peng-Fei; Joshi, Navin Chandra; Zhou, Yu-Hao
Bibcode: 2015RAA....15.1713P
Altcode: 2015arXiv150302281P
We report and analyze observational evidence of global kink oscillations
in a solar filament as observed in Hα by instruments administered
by National Solar Observatory (NSO)/Global Oscillation Network Group
(GONG). An M1.1-class flare in active region (AR) 11692 occurred on
2013 March 15 and induced a global kink mode in the filament lying
towards the southwest of AR 11692. We find periods of about 61-67
minutes and damping times of 92-117 minutes at positions of three
vertical slices chosen in and around the filament apex. We find that
the waves are damped. From the observed period of the global kink
mode and damping timescale using the theory of resonant absorption,
we perform prominence seismology. We estimate a lower cut-off value
for the inhomogeneity length scale to be around 0.34-0.44 times the
radius of the filament cross-section.
Title: Statistics of X-Ray Flares of Sagittarius A*: Evidence for
Solar-like Self-organized Criticality Phenomena
Authors: Li, Ya-Ping; Yuan, Feng; Yuan, Qiang; Wang, Q. Daniel; Chen,
P. F.; Neilsen, Joseph; Fang, Taotao; Zhang, Shuo; Dexter, Jason
Bibcode: 2015ApJ...810...19L
Altcode: 2015arXiv150602946L
X-ray flares have routinely been observed from the supermassive black
hole at our Galactic center, Sagittarius A{}\star (Sgr
A⋆). The nature of these flares remains largely unclear,
despite many theoretical models. In this paper, we study the statistical
properties of the Sgr A⋆ X-ray flares by fitting the count
rate (CR) distribution and the structure function of the light curve
with a Markov Chain Monte Carlo method. With the 3-million-second
Chandra observations accumulated in the Sgr A⋆ X-ray
Visionary Project, we construct the theoretical light curves through
Monte Carlo simulations. We find that the 2-8 keV X-ray light curve
can be decomposed into a quiescent component with a constant CR of
6× {10}-3 count s-1 and a flare component
with a power-law fluence distribution {dN}/{dE}\propto {E}-{α
{{E}}} with {α }{{E}}=1.65+/- 0.17. The
duration-fluence correlation can also be modeled as a power law T\propto
{E}{α {ET}} with {α }{ET}\lt 0.55
(95% confidence). These statistical properties are consistent with
the theoretical prediction of the self-organized criticality system
with the spatial dimension S = 3. We suggest that the X-ray flares
represent plasmoid ejections driven by magnetic reconnection (similar
to solar flares) in the accretion flow onto the black hole.
Title: Diagnostics of Ellerman bombs with high-resolution spectral
data
Authors: Li, Zhen; Fang, Cheng; Guo, Yang; Chen, Peng-Fei; Xu, Zhi;
Cao, Wen-Da
Bibcode: 2015RAA....15.1513L
Altcode: 2015arXiv150402538L
Ellerman bombs (EBs) are tiny brightenings often observed near
sunspots. The most impressive characteristic of EB spectra is
the two emission bumps in both wings of the Hα and Ca II 8542Å
lines. High-resolution spectral data of three small EBs were obtained
on 2013 June 6 with the largest solar telescope, the 1.6 m New Solar
Telescope at the Big Bear Solar Observatory. The characteristics
of these EBs are analyzed. The sizes of the EBs are in the range
of 0.3‧ - 0.8‧ and their durations are only 3-5 min. Our
semi-empirical atmospheric models indicate that the heating occurs
around the temperature minimum region with a temperature increase of
2700-3000 K, which is surprisingly higher than previously thought. The
radiative and kinetic energies are estimated to be as high as 5 ×
1025 - 3.0 × 1026 erg despite the small size
of these EBs. Observations of the magnetic field show that the EBs
just appeared in a parasitic region with mixed polarities and were
accompanied by mass motions. Nonlinear force-free field extrapolation
reveals that the three EBs are connected with a series of magnetic field
lines associated with bald patches, which strongly implies that these
EBs should be produced by magnetic reconnection in the solar lower
atmosphere. According to the lightcurves and the estimated magnetic
reconnection rate, we propose that there is a three phase process in
EBs: pre-heating, flaring and cooling phases.
Title: A Two-ribbon White-light Flare Associated with a Failed Solar
Eruption Observed by ONSET, SDO, and IRIS
Authors: Cheng, X.; Hao, Q.; Ding, M. D.; Liu, K.; Chen, P. F.; Fang,
C.; Liu, Y. D.
Bibcode: 2015ApJ...809...46C
Altcode: 2015arXiv150702109C
Two-ribbon brightenings are one of the most remarkable characteristics
of an eruptive solar flare and are often used to predict the
occurrence of coronal mass ejections (CMEs). Nevertheless, it was
recently called into question whether all two-ribbon flares are
eruptive. In this paper, we investigate a two-ribbon-like white-light
(WL) flare that is associated with a failed magnetic flux rope
(MFR) eruption on 2015 January 13, which has no accompanying CME in
the WL coronagraph. Observations by the Optical and Near-infrared
Solar Eruption Tracer and the Solar Dynamics Observatory reveal
that with the increase of the flare emission and the acceleration
of the unsuccessfully erupting MFR, two isolated kernels appear
at the WL 3600 Å passband and quickly develop into two elongated
ribbon-like structures. The evolution of the WL continuum enhancement
is completely coincident in time with the variation of Fermi hard
X-ray 26-50 keV flux. An increase of continuum emission is also
clearly visible at the whole FUV and NUV passbands observed by the
Interface Region Imaging Spectrograph. Moreover, in one WL kernel,
the Si iv, C ii, and Mg ii h/k lines display significant enhancement
and non-thermal broadening. However, their Doppler velocity pattern
is location-dependent. At the strongly bright pixels, these lines
exhibit a blueshift, while at moderately bright ones, the lines are
generally redshifted. These results show that the failed MFR eruption
is also able to produce a two-ribbon flare and high-energy electrons
that heat the lower atmosphere, causing the enhancement of the WL and
FUV/NUV continuum emissions and chromospheric evaporation.
Title: Slow Patchy Extreme-ultraviolet Propagating Fronts Associated
with Fast Coronal Magneto-acoustic Waves in Solar Eruptions
Authors: Guo, Y.; Ding, M. D.; Chen, P. F.
Bibcode: 2015ApJS..219...36G
Altcode:
Using the high spatiotemporal resolution extreme ultraviolet (EUV)
observations of the Atmospheric Imaging Assembly on board the
Solar Dynamics Observatory, we conduct a statistical study of the
observational properties of the coronal EUV propagating fronts. We
find that it might be a universal phenomenon for two types of fronts
to coexist in a large solar eruptive event. It is consistent with the
hybrid model of EUV propagating fronts, which predicts that coronal
EUV propagating fronts consist of both a fast magneto-acoustic wave
and a nonwave component. We find that the morphologies, propagation
behaviors, and kinematic features of the two EUV propagating fronts are
completely different from each other. The fast magneto-acoustic wave
fronts are almost isotropic. They travel continuously from the flaring
region across multiple magnetic polarities to global distances. On
the other hand, the slow nonwave fronts appear as anisotropic and
sequential patches of EUV brightening. Each patch propagates locally
in the magnetic domains where the magnetic field lines connect to the
bottom boundary and stops at the magnetic domain boundaries. Within
each magnetic domain, the velocities of the slow patchy nonwave
component are an order of magnitude lower than that of the fast-wave
component. However, the patches of the slow EUV propagating front can
jump from one magnetic domain to a remote one. The velocities of such
a transit between different magnetic domains are about one-third to
one-half of those of the fast-wave component. The results show that the
velocities of the nonwave component, both within one magnetic domain
and between different magnetic domains, are highly nonuniform due to
the inhomogeneity of the magnetic field in the lower atmosphere.
Title: Modelling of radio emission in the SLAC T-510 Experiment
using microscopic Geant4 simulations
Authors: Zilles, A.; Bechtol, K.; Belov, K.; Borch, K.; Chen, P.; Clem,
J.; Gorham, P.; Hast, C.; Huege, T.; Hyneman, R.; Jobe, K.; Kuwatani,
K.; Lam, J.; Liu, T.; Mulrey, K.; Nam, J.; Naudet, C.; Nichol, R. J.;
Rauch, B. F.; Romero-Wolf, A.; Rotter, B.; Saltzberg, D.; Schoorlemmer,
H.; Seckel, D.; Strutt, B.; Vieregg, A.; Williams, C.; Wissel, S.
Bibcode: 2015ICRC...34..313Z
Altcode: 2015PoS...236..313Z
No abstract at ADS
Title: SLAC T-510: A beam-line experiment for radio emission from
particle cascades in the presence of a magnetic field
Authors: Belov, K.; Bechtol, K.; Borch, K.; Chen, P.; Clem, J.; Gorham,
P.; Hast, C.; Huege, T.; Hyneman, R.; Jobe, K.; Kuwatani, K.; Lam, J.;
Liu, T.; Mulrey, K.; Nam, J.; Naudet, C.; Nichol, R. J.; Rauch, B. F.;
Romero-Wolf, A.; Rotter, B.; Saltzberg, D.; Schoorlemmer, H.; Seckel,
D.; Strutt, B.; Vieregg, A.; Williams, C.; Wissel, S.; Zilles, A.
Bibcode: 2015ICRC...34..346B
Altcode: 2015PoS...236..346B
No abstract at ADS
Title: Measurements, system response, and calibration of the SLAC
T-510 Experiment
Authors: Wissel, S.; Bechtol, K.; Belov, K.; Borch, K.; Chen, P.; Clem,
J.; Gorham, P.; Hast, C.; Huege, T.; Hyneman, R.; Jobe, K.; Kuwatani,
K.; Lam, J.; Liu, T.; Mulrey, K.; Nam, J.; Naudet, C.; Nichol, R. J.;
Rauch, B. F.; Romero-Wolf, A.; Rotter, B.; Saltzberg, D.; Schoorlemmer,
H.; Seckel, D.; Strutt, B.; Vieregg, A.; Williams, C.; Zilles, A.
Bibcode: 2015ICRC...34..342W
Altcode: 2015PoS...236..342W
No abstract at ADS
Title: Supernova 2015L
Authors: Dong, S.; Shappee, B. J.; Prieto, J. L.; Jha, S. W.; Stanek,
K. Z.; Holoien, T. W. -S.; Kochanek, C. S.; Thompson, T. A.; Morrell,
N.; Thompson, I. B.; Basu, U.; Beacom, J. F.; Bersier, D.; Brimacombe,
J.; Brown, J. S.; Chen, P.; Conseil, E.; Danilet, A. B.; Falco, E.;
Grupe, D.; Kiyota, S.; Masi, G.; Nicholls, B.; Olivares, F.; Pignata,
G.; Pojmanski, G.; Simonian, G. V.; Szczygiel, D. M.; Wozniak, P. R.
Bibcode: 2015CBET.4120....1D
Altcode: 2015CBET.4120A...1D
Subo Dong, Kavli Institute for Astronomy and Astrophysics, Peking
University; B. J. Shappee, Carnegie Observatories; J. L. Prieto,
Universidad Diego Portales; S. W. Jha, Rutgers University;
K. Z. Stanek, T. W.-S. Holoien, C. S. Kochanek, and T. A. Thompson,
Ohio State University (OSU); N. Morrell and I. B. Thompson,
Carnegie Observatories; U. Basu and J. F. Beacom, OSU; D. Bersier,
Liverpool John Moores University; J. Brimacombe, Cairns, Australia;
J. S. Brown, OSU; P. Chen, Peking University; E. Conseil, Association
Francaise des Observateurs d'Etoiles Variables; A. B. Danilet, OSU;
E. Falco, Harvard-Smithsonian Center for Astrophysics; D. Grupe,
Morehead Sate University; S. Kiyota, Kamagaya, Japan; G. Masi,
Ceccano, Italy; B. Nicholls, Mt. Vernon Observatory; F. Olivares and
G. Pignata, Universidad Andres Bello; G. Pojmanski, Warsaw University
Astronomical Observatory; G. V. Simonian, OSU; D. M. Szczygiel, Warsaw
University Astronomical Observatory; and P. R. Wozniak, Los Alamos
National Laboratory, report the discovery of an apparent supernova
(V magnitude about 17.0) on images obtained in the course of the "All
Sky Automated Survey for SuperNovae (ASAS-SN)" with the double 14-cm
"Cassius" telescope at Cerro Tololo on June 14.25 UT. The new object is
located at R.A. = 22h02m15s.45, Decl. = -61d39'34".6 (equinox 2000.0),
which is approximately 0".41 ast and 0".04 south of the center of the
galaxy APMUKS(BJ) B215839.70-615403.9. Additional magnitudes for the
variable: May 15.33, [17.3; 18.32, 17.3 (marginal detection); 22.32,
17.2; 26.31, 17.0; 27.34, 16.9; June 8.36, 16.9; 9.25, 16.8; 11.40,
17.1; 12.22, 17.1; 13.23, 16.9.
Title: Extreme ultraviolet imaging of three-dimensional magnetic
reconnection in a solar eruption
Authors: Sun, J. Q.; Cheng, X.; Ding, M. D.; Guo, Y.; Priest, E. R.;
Parnell, C. E.; Edwards, S. J.; Zhang, J.; Chen, P. F.; Fang, C.
Bibcode: 2015NatCo...6.7598S
Altcode: 2015NatCo...6E7598S; 2015arXiv150608255S
Magnetic reconnection, a change of magnetic field connectivity, is
a fundamental physical process in which magnetic energy is released
explosively, and it is responsible for various eruptive phenomena in the
universe. However, this process is difficult to observe directly. Here,
the magnetic topology associated with a solar reconnection event is
studied in three dimensions using the combined perspectives of two
spacecraft. The sequence of extreme ultraviolet images clearly shows
that two groups of oppositely directed and non-coplanar magnetic loops
gradually approach each other, forming a separator or quasi-separator
and then reconnecting. The plasma near the reconnection site is
subsequently heated from ~1 to >=5 MK. Shortly afterwards, warm flare
loops (~3 MK) appear underneath the hot plasma. Other observational
signatures of reconnection, including plasma inflows and downflows, are
unambiguously revealed and quantitatively measured. These observations
provide direct evidence of magnetic reconnection in a three-dimensional
configuration and reveal its origin.
Title: A Type II Radio Burst without a Coronal Mass Ejection
Authors: Su, W.; Cheng, X.; Ding, M. D.; Chen, P. F.; Sun, J. Q.
Bibcode: 2015ApJ...804...88S
Altcode: 2015arXiv150300861S
Type II radio bursts are thought to be a signature of coronal shocks. In
this paper, we analyze a short-lived type II burst that started at 07:40
UT on 2011 February 28. By carefully checking white-light images, we
find that the type II radio burst is not accompanied by a coronal mass
ejection, only by a C2.4 class flare and narrow jet. However, in the EUV
images provided by the Atmospheric Imaging Assembly on board the Solar
Dynamics Observatory, we find a wave-like structure that propagated at
a speed of ∼600 km s-1 during the burst. The relationship
between the type II radio burst and the wave-like structure is, in
particular, explored. For this purpose, we first derive the density
distribution under the wave by the differential emission measure method,
which is used to restrict the empirical density model. We then use the
restricted density model to invert the speed of the shock that produces
the observed frequency drift rate in the dynamic spectrum. The inverted
shock speed is similar to the speed of the wave-like structure. This
implies that the wave-like structure is most likely a coronal shock
that produces the type II radio burst. We also examine the evolution
of the magnetic field in the flare-associated active region and find
continuous flux emergence and cancellation taking place near the flare
site. Based on these facts, we propose a new mechanism for the formation
of the type II radio burst, i.e., the expansion of the strongly inclined
magnetic loops after reconnecting with a nearby emerging flux acts as
a piston to generate the shock wave.
Title: Physical properties of Planck Cold Dust Clumps
Authors: Wu, Y.; Liu, T.; Meng, F.; Yuan, J.; Zhang, T.; Chen, P.;
Hu, R.; Li, D.; Qin, S.; Ju, B.
Bibcode: 2015EAS....75..277W
Altcode: 2016EAS....75..277W
To explore physical properties of Planck cold dust clumps, 674
of the pilot samples were observed at the 13.7 m telescope of
Purple Mountain Observatory (PMO) in J = 1 - 0 transitions of
CO, 13CO and C18O. HCO+, HCN and
N2H+ emissions were also observed with PMO 13.7
m and IRAM 30 m telescopes. They are real cold and quiescent with
mean Tk ∼ 10 K and mean FWHM of 13CO (1-0)
1.27 km s-1. Column density ranges from 1020
to 1022 cm-2. Gas of the Planck clumps
extends molecular space in the Milky Way. Turbulence dominates in
cores. Filament structure is the majority and most of the cores are
starless. Ten percent of the cores show asymmetric emission features
including blue- and red- profiles. Planck clumps include different cold
or low luminosity sources. Dense cores constitute an ideal sample for
studying initial state of star formation while the diffuse clumps are
suitable for investigating the formation of cores.
Title: Research on global plasmaspheric electron content by using
LEO occultation and GPS data
Authors: Chen, Peng; Yao, Yibin
Bibcode: 2015AdSpR..55.2248C
Altcode:
This paper investigates the characteristics of global plasmaspheric
electron content (pTEC) using COSMIC (Constellation Observing System
for Meteorology, Ionosphere and Climate) occultation and GPS (Global
Positioning System) data. The ionospheric electron content (iTEC)
within 100-1000 km was obtained by fitting the COSMIC occultation
electron density profiles, and the pTEC was obtained by subtracting
the iTEC from CODE (Center for Orbit Determination in Europe) GIM
(global ionosphere maps) TEC provided by University of Bern. This
paper also investigates the characteristics of pTEC variations with
local time, latitude and season. The results show that in 2011, the
worldwide average of pTEC was 4.02 TECu, which is consistent with
the findings of other studies. The pTEC shows significant diurnal
variation characteristics, that is, pTEC is higher during daytime than
during nighttime, but the percentage contribution of pTEC to GPS TEC
is higher during nighttime than during daytime. The pTEC varies with
the seasons, pTEC hemispheres symmetrically during spring and autumn,
while pTEC in the summer hemisphere is higher than that in the winter
hemisphere. Moreover, the percentage contribution of pTEC to GPS TEC
(total electron content) is higher in winter hemisphere than in summer
hemisphere.
Title: Magnetohydrodynamic Seismology of a Coronal Loop System by
the First Two Modes of Standing Kink Waves
Authors: Guo, Y.; Erdélyi, R.; Srivastava, A. K.; Hao, Q.; Cheng,
X.; Chen, P. F.; Ding, M. D.; Dwivedi, B. N.
Bibcode: 2015ApJ...799..151G
Altcode: 2014arXiv1411.7095G
We report the observation of the first two harmonics of the horizontally
polarized kink waves excited in a coronal loop system lying southeast of
AR 11719 on 2013 April 11. The detected periods of the fundamental mode
(P 1), its first overtone (P 2) in the northern
half, and that in the southern one are 530.2 ± 13.3, 300.4 ± 27.7, and
334.7 ± 22.1 s, respectively. The periods of the first overtone in the
two halves are the same considering uncertainties in the measurement. We
estimate the average electron density, temperature, and length of
the loop system as (5.1 ± 0.8) × 108 cm-3,
0.65 ± 0.06 MK, and 203.8 ± 13.8 Mm, respectively. As a zeroth-order
estimation, the magnetic field strength, B = 8.2 ± 1.0 G, derived by
the coronal seismology using the fundamental kink mode matches with
that derived by a potential field model. The extrapolation model also
shows the asymmetric and nonuniform distribution of the magnetic field
along the coronal loop. Using the amplitude profile distributions of
both the fundamental mode and its first overtone, we observe that the
antinode positions of both the fundamental mode and its first overtone
shift toward the weak field region along the coronal loop. The results
indicate that the density stratification and the temperature difference
effects are larger than the magnetic field variation effect on the
period ratio. On the other hand, the magnetic field variation has a
greater effect on the eigenfunction of the first overtone than the
density stratification does for this case.
Title: Methane on Mars
Authors: Chen, P.; Yung, Y. L.
Bibcode: 2015JAsBO...3..125C
Altcode:
No abstract at ADS
Title: Preparation and characterization of GaN micro/nano- structures
by the electrodeless photo-assisted chemical etching
Authors: Zhang, Shiying; Xiu, Xiangqian; Xu, Qingjun; Wang, Hengyuan;
Hua, Xuemei; Xie, Zili; Liu, Bin; Chen, Peng; Han, Ping; Lu, Hai;
Gu, Shulin; Zhang, Rong; Zheng, Youliao
Bibcode: 2015SSPMA..45h7301Z
Altcode:
No abstract at ADS
Title: An interferometric analysis method for radio impulses from
ultra-high energy particle showers
Authors: Romero-Wolf, A.; Hoover, S.; Vieregg, A. G.; Gorham, P. W.;
Allison, P.; Barwick, S. W.; Baughman, B. M.; Beatty, J. J.; Belov,
K.; Besson, D. Z.; Bevan, S.; Binns, W. R.; Chen, C.; Chen, P.; Clem,
J. M.; Connolly, A.; Detrixhe, M.; De Marco, D.; Dowkontt, P. F.;
DuVernois, M.; Goldstein, D.; Grashorn, E. W.; Hill, B.; Huang, M.;
Israel, M. H.; Javaid, A.; Kowalski, J.; Learned, J.; Liewer, K. M.;
Matsuno, S.; Mercurio, B. C.; Miki, C.; Mottram, M.; Nam, J.; Naudet,
C. J.; Nichol, R. J.; Palladino, K.; Ruckman, L.; Saltzberg, D.;
Seckel, D.; Shang, R. Y.; Stockham, J.; Stockham, M.; Varner, G. S.;
Wang, Y.
Bibcode: 2015APh....60...72R
Altcode:
We present an interferometric technique for the reconstruction of
ultra-wide band impulsive signals from point sources. This highly
sensitive method was developed for the search for ultra-high energy
neutrinos with the ANITA experiment but is fully generalizable to
any antenna array detecting radio impulsive events. Applications
of the interferometric method include event reconstruction, thermal
noise and anthropogenic background rejection, and solar imaging for
calibrations. We illustrate this technique with applications from the
analysis of the ANITA-I and ANITA-II data in the 200-1200 MHz band.
Title: ASAS-SN Discovery of A Probable Supernova in VV 839.
Authors: Conseil, E.; Dong, S.; Brown, J. S.; Stanek, K. Z.; Holoien,
T. W. -S.; Kochanek, C. S.; Godoy-Rivera, D.; Basu, U.; Shappee,
B. J.; Prieto, J. L.; Bersier, D.; Chen, P.; Brimacombe, J.
Bibcode: 2015ATel.8491....1C
Altcode:
No abstract at ADS
Title: Observation of early photons from gamma-ray bursts with the
Lomonosov / UFFO-pathfinder
Authors: Jeong, S.; Brandt, S.; Budtz-Jørgensen, C.; Castro-Tirado,
A. J.; Chen, P.; Connell, P.; Eyles, C.; Huang, M. -H. A.; Kim, J. E.;
Kim, M. B.; Kim, S. -W.; Lee, J.; Lim, H.; Liu, T. -C.; Nam, J. W.;
Park, H. W.; Park, I. H.; Panasyuk, M. I.; Reglero, V.; Ripa, J.;
Rodrigo, J. M.; Svertilov, S.; Vedenkin, N.; Yashin, I.
Bibcode: 2014RMxAC..45..139J
Altcode:
UFFO-pathfinder is a pioneering space mission to observe the early
evolution of Gamma-ray Bursts using a fast slewing strategy. It consists
of the Slewing Mirror Telescope, for rapid pointing at UV/optical
wavelengths and the UFFO Burst Alert and Trigger Telescope. It has a
total weight of ∼ 20 kg and will be launched on-board the Russian
Lomonosov satellite at the end of 2015. The instrumental details of
UFFO-pathfinder and its performance are discussed briefly here.
Title: Study of the 2013 Lushan M7.0 earthquake coseismic ionospheric
disturbances
Authors: Chen, Peng; Yao, Yibin; Chen, Jiajun; Yao, Wanqiang; Zhu,
Xuejun
Bibcode: 2014AdSpR..54.2194C
Altcode:
On April 20, 2013, an earthquake of M7.0 occurred in Lushan, Sichuan
province, China. This paper investigates the coseismic ionospheric
anomalies using GPS (Global Positioning System) data from 23 reference
stations in Sichuan province that are a part of the Crustal Movement
Observation Network of China (CMONOC). The recorded results show that a
clear ionospheric anomaly occurred within 15 min after the earthquake
near the epicenter, and the occurrence time of the anomalies recorded
by various stations is related to the distance from the epicenter. The
maximum anomaly is 0.25 TECu, with a 2 min duration and the distance
of the recording station to the epicenter is 83 km. Acoustic waves
generated by the crustal vertical movement during the earthquake
propagate up to the height of the ionosphere lead to the ionospheric
anomaly, and the propagation speed of the acoustic wave is calculated
as 0.72 ± 0.04 km/s based on the propagation time and propagation
distance, consistent with the average speed of sound waves within a
0-450 km atmospheric height.
Title: Testing and Performance of UFFO Burst Alert & Trigger
Telescope
Authors: Ripa, J.; Kim, M. B.; Jeong, S.; Eyles, C.; Rodrigo, J. M.;
Bogomolov, V.; Budtz-Jørgensen, C.; Chen, C. R.; Choi, H. S.; Lee,
J.; Park, H.; Kim, E.; Castro-Tirado, A. J.; Connell, P.; Reglero,
V.; Panasyuk, M. I.; Petrov, V.; Svertilov, S.; Yashin, I.; Brandt,
S.; Chang, Y.; Chen, P.; Huang, M. A.; Liu, T. C.; Nam, J.; Wang, M. Z.
Bibcode: 2014styd.confE.102R
Altcode: 2015arXiv150705696R; 2014PoS...233E.102R
The Ultra-Fast Flash Observatory pathfinder (UFFO-p) is a new space
mission dedicated to detect Gamma-Ray Bursts (GRBs) and rapidly
follow their afterglows in order to provide early optical/ultraviolet
measurements. A GRB location is determined in a few seconds by
the UFFO Burst Alert & Trigger telescope (UBAT) employing
the coded mask imaging technique and the detector combination of
Yttrium Oxyorthosilicate (YSO) scintillating crystals and multi-anode
photomultiplier tubes. The results of the laboratory tests of UBAT's
functionality and performance are described in this article. The
detector setting, the pixel-to-pixel response to X-rays of different
energies, the imaging capability for <50 keV X-rays, the localization
accuracy measurements, and the combined test with the Block for X-ray
and Gamma-Radiation Detection (BDRG) scintillator detector to check
the efficiency of UBAT are all described. The UBAT instrument has been
assembled and integrated with other equipment on UFFO-p and should be
launched on board the Lomonosov satellite in late-2015.
Title: Testing a Simple Recipe for Estimating Thermal Hydrodynamic
Escape Rates in Primitive Terrestrial Atmospheres
Authors: Friedson, A. J.; Yung, Y. L.; Chen, P.
Bibcode: 2014AGUFM.P53C4026F
Altcode:
During the first billion years of the Sun's history, the emission of
ultraviolet and X-ray radiation varied from ~100 to ~6 times greater
than its present level. The absorption of this intense radiation in the
upper atmospheres of the terrestrial planets is believed to have driven
rapid hydrodynamic escape, either in the form of energy-limited escape
or transonic blow-off. The calculation of escape rates under these
circumstances, and in particular the nature of the correct condition
to apply at the upper boundary, depends on whether or not the flow
remains subsonic below the exobase. If the flow remains subsonic,
the kinetic Jeans equations may be applied at the exobase; otherwise,
the radius of the sonic point must be located and then appropriate
boundary conditions applied at this radius. This seems to suggest that
the full hydrodynamic escape problem needs to be solved iteratively
to determine where the sonic radius falls and the type of boundary
conditions that should be applied. Such an arduous undertaking is
generally impractical for standard application in chemical evolution
models or related studies. Fortunately, a much easier but still accurate
approach to determining whether the flow remains subsonic below the
exobase for a given amount of energy deposition has been provided by
Johnson et al. (2013, Ap. J. Lett. 768:L4), who base their results on
rigorous Discrete Simulation Monte Carlo models. Their model provides
the ratio of the escape rate to the energy-limited value as a function
of the total XUV heating. The XUV heating, however, is itself coupled to
the escape rate through the radial structure of the upper atmosphere,
which can become greatly distended for large heating rates. Here we
present a simple recipe for estimating the hydrodynamic escape rate that
includes the coupling between the escape rate, the radial structure,
and the XUV heating while avoiding the use of demanding numerical
calculations. The approach involves an iterative semi-analytical
method for determining the effective radius of energy deposition,
from which the escape rate, radial structure, and other parameters
can be derived. We test its performance against some more elaborate,
rigorous calculations of primitive-atmosphere hydrodynamic escape that
are available in the literature.
Title: Marine Targets Classification in PolInSAR Data
Authors: Chen, Peng; Yang, Jingsong; Ren, Lin
Bibcode: 2014ESASP.724E..80C
Altcode:
In this paper, marine stationary targets and moving targets are studied
by Pol-In-SAR data of Radarsat-2. A new method of stationary targets
detection is proposed. The method get the correlation coefficient
image of the In-SAR data, and using the histogram of correlation
coefficient image. Then, A Constant False Alarm Rate (CFAR) algorithm
and The Probabilistic Neural Network model are imported to detect
stationary targets. To find the moving targets, Azimuth Ambiguity is
show as an important feature. We use the length of azimuth ambiguity
to get the target's moving direction and speed. Make further efforts,
Targets classification is studied by rebuild the surface elevation of
marine targets.
Title: Marine Targets Classification in PolInSAR Data
Authors: Chen, Peng; Yang, Jingsong; Ren, Lin
Bibcode: 2014ESASP.724...80C
Altcode:
In this paper, marine stationary targets and moving targets are studied
by Pol-In-SAR data of Radarsat-2. A new method of stationary targets
detection is proposed. The method get the correlation coefficient image
of the In-SAR data, and using the histogram of correlation coefficient
image. Then , A Constant False Alarm Rate (CFAR) algorithm and The
Probabilistic Neural Network model are imported to detect stationary
targets. To find the moving targets, Azimuth Ambiguity is show as an
important feature. We use the length of azimuth ambiguity to get the
target's moving direction and speed. Make further efforts, Targets
classification is studied by rebuild the surface elevation of marine
targets.
Title: Simultaneous Transverse Oscillations of a Prominence and a
Filament and Longitudinal Oscillation of Another Filament Induced
by a Single Shock Wave
Authors: Shen, Yuandeng; Liu, Ying D.; Chen, P. F.; Ichimoto, Kiyoshi
Bibcode: 2014ApJ...795..130S
Altcode: 2014arXiv1409.1304S
We present the first stereoscopic and Doppler observations of
simultaneous transverse oscillations of a prominence and a filament and
longitudinal oscillation of another filament launched by a single shock
wave. Using Hα Doppler observations, we derive the three-dimensional
oscillation velocities at different heights along the prominence
axis. The results indicate that the prominence has a larger oscillation
amplitude and damping time at higher altitude, but the periods at
different heights are the same (i.e., 13.5 minutes). This suggests that
the prominence oscillates like a linear vertical rigid body with one
end anchored on the Sun. One of the filaments shows weak transverse
oscillation after the passing of the shock, which is possibly due to
the low altitude of the filament and the weakening (due to reflection)
of the shock wave before the interaction. Large-amplitude longitudinal
oscillation is observed in the other filament after the passing of
the shock wave. The velocity amplitude and period are about 26.8 km
s-1 and 80.3 minutes, respectively. We propose that the
orientation of a filament or prominence relative to the normal vector
of the incoming shock should be an important factor for launching
transverse or longitudinal filament oscillations. In addition, the
restoring forces of the transverse prominence are most likely due
to the coupling of gravity and magnetic tension of the supporting
magnetic field, while that for the longitudinal filament oscillation
is probably the resultant force of gravity and magnetic pressure.
Title: Realization of global empirical model for mapping zenith wet
delays onto precipitable water using NCEP re-analysis data
Authors: Chen, Peng; Yao, Wanqiang; Zhu, Xuejun
Bibcode: 2014GeoJI.198.1748C
Altcode:
Considering the drawback of existing global weighted mean temperature
model, this paper uses 2006-2012 NCEP reanalysis data to establish
global empirical model for mapping zenith wet delays onto precipitable
water-GTm_N, takes the influence of half-year periodicity of Tm into
account when modelling and estimate the initial phase of each cycle. In
order to evaluate the precision of GTm_N, we use three different Tm
data sets from the NCEP during 2013, 650 radiosonde stations and COSMIC
occultation in 2011 to test this model. The results show that GTm_N has
higher precision in both ocean and continental area in every moment
of every day. The accuracy of GTm_N is higher than Bevis formulas
and GTm_II models. In addition, the actual surface temperature is
not required in GTm_N model, and it will have wide application in
GPS meteorology.
Title: Reciprocatory magnetic reconnection in a coronal bright point
Authors: Zhang, Q. M.; Chen, P. F.; Ding, M. D.; Ji, H. S.
Bibcode: 2014A&A...568A..30Z
Altcode: 2014arXiv1406.5328Z
Context. Coronal bright points (CBPs) are small-scale and long-duration
brightenings in the lower solar corona. They are often explained
in terms of magnetic reconnection.
Aims: We aim to study
the substructures of a CBP and clarify the relationship among the
brightenings of different patches inside the CBP.
Methods:
The event was observed by the X-ray Telescope (XRT) aboard the Hinode
spacecraft on 2009 August 22-23.
Results: The CBP showed repeated
brightenings (or CBP flashes). During each of the two successive CBP
flashes, that is, weak and strong flashes that were separated by ~2
hr, the XRT images revealed that the CBP was composed of two chambers,
patches A and B. During the weak flash, patch A brightened first, and
patch B brightened ~2 min later. During the transition, the right leg of
a large-scale coronal loop drifted from the right side of the CBP to the
left side. During the strong flash, patch B brightened first, and patch
A brightened ~2 min later. During the transition, the right leg of the
large-scale coronal loop drifted from the left side of the CBP to the
right side. In each flash, the rapid change of the connectivity of the
large-scale coronal loop is strongly suggestive of the interchange
reconnection.
Conclusions: For the first time we found
reciprocatory reconnection in the CBP, which means that reconnected
loops in the outflow region of the first reconnection process
serve as the inflow of the second reconnection process. Movies
associated with Figs. 2 and 5 are available in electronic form at http://www.aanda.org
Title: On the Relationship Between a Hot-channel-like Solar Magnetic
Flux Rope and its Embedded Prominence
Authors: Cheng, X.; Ding, M. D.; Zhang, J.; Srivastava, A. K.; Guo,
Y.; Chen, P. F.; Sun, J. Q.
Bibcode: 2014ApJ...789L..35C
Altcode: 2014arXiv1406.4196C
A magnetic flux rope (MFR) is a coherent and helical magnetic
field structure that has recently been found likely to appear as an
elongated hot channel prior to a solar eruption. In this Letter, we
investigate the relationship between the hot channel and the associated
prominence through analysis of a limb event on 2011 September 12. In
the early rise phase, the hot channel was initially cospatial with
the prominence. It then quickly expanded, resulting in a separation
of the top of the hot channel from that of the prominence. Meanwhile,
they both experienced an instantaneous morphology transformation from
a Λ shape to a reversed-Y shape and the top of these two structures
showed an exponential increase in height. These features are a good
indication of the occurrence of kink instability. Moreover, the onset
of kink instability is found to coincide in time with the impulsive
enhancement of flare emission underneath the hot channel, suggesting
that ideal kink instability likely also plays an important role in
triggering fast flare reconnection besides initiating the impulsive
acceleration of the hot channel and distorting its morphology. We
conclude that the hot channel is most likely the MFR system and the
prominence only corresponds to the cool materials that are collected
in the bottom of the helical field lines of the MFR against gravity.
Title: Single-Molecule Microscopy of Nanocatalysis
Authors: Chen, Peng
Bibcode: 2014isms.confEMA03C
Altcode:
Nanoparticles are important catalysts. Understanding their
structure-activity correlation is paramount for developing better
catalysts, but hampered by their inherent inhomogeneity: individual
nanoparticles differ from one to another, and for every nanoparticle, it
can change from time to time, especially during catalysis. Furthermore,
each nanoparticle presents on its surface various types of sites,
which are often unequal in catalytic activity. I will present our
work of using single-molecule fluorescence microscopy to overcome
these challenges and study single-nanoparticle catalysis at the
single-turnover resolution and nanometer precision. I will present
how we interrogate the catalytic activity and dynamics of individual
metal nanoparticles, map the reactivity of different surface sites,
and uncover surprising spatial reactivity patterns within single
facets at the nanoscale. This spatiotemporally resolved catalysis
mapping also enables us to probe the communication between catalytic
reactions at different locations on a single nanocatalyst, in much
relation to allosteric effects in enzymes.
Title: The multi-source data fusion global ionospheric modeling
software-IonoGim
Authors: Chen, Peng; Chen, Jiajun
Bibcode: 2014AdSpR..53.1610C
Altcode:
We introduce a new global ionospheric modeling software-IonoGim, using
ground-based GNSS data, the altimetry satellite and LEO (Low Earth
Orbit) occultation data to establish the global ionospheric model. The
software is programmed by C++ with fast computing speed and highly
automatic degree, it is especially suitable for automatic ionosphere
modeling. The global ionospheric model and DCBs obtained from IonoGim
were compared with the CODE (Center for Orbit Determination in Europe)
to verify its accuracy and reliability. The results show that IonoGim
and CODE have good agreement with small difference, indicating that
IonoGim owns high accuracy and reliability, and can be fully applicable
for high-precision ionospheric research. In addition, through comparison
between only using ground-based GNSS observations and multi-source
data model, it can be demonstrated that the space-based ionospheric
data effectively improve the model precision in marine areas where
the ground-based GNSS tracking station lacks.
Title: Characteristics of the Photospheric Magnetic Field Associated
with Solar Flare Initiation
Authors: Yang, Ya-Hui; Chen, P. F.; Hsieh, Min-Shiu; Wu, S. T.; He,
Han; Tsai, Tsung-Che
Bibcode: 2014ApJ...786...72Y
Altcode:
The physical environment governing the solar flare initiation is not
fully understood, although there are significant efforts to address
the relationship between magnetic non-potential parameters and early
flare signatures. In this study, we attempt to characterize the flare
initiation based on the processed Helioseismic and Magnetic Imager
vector magnetograms, Atmospheric Imaging Assembly 1600 Å, and RHESSI
hard X-ray observations. Three flare events, the M6.6 flare on 2011
February 13, the X2.2 flare on 2011 February 15, and the X2.1 flare
on 2011 September 6, in two active regions AR 11158 and AR 11283 are
investigated. We analyze the source field strength in the photosphere,
which is defined as the magnitude of the observed magnetic field
deviation from the potential field. It is found that one of the strong
source field regions above the magnetic polarity inversion line well
connects the initial bright kernels of two conjugate ribbons. The
results imply that the distribution of the photospheric source field
strength can be used to locate the initiation site of flaring loops
regardless of the configuration of pre-flare magnetic fields or the
evolution of active regions. Moreover, the field configuration in the
strong source field regions tends to become more inclined after flares,
which is consistent with the coronal implosion scenario. We also employ
a fast method to derive the total current density from the photospheric
vector magnetogram in the framework of force-free field. This method
can provide fast estimation of photospheric current density within a
reasonable accuracy without appealing for the more accurate calculation
from a model extrapolation.
Title: Laser cosmology
Authors: Chen, P.
Bibcode: 2014EPJST.223.1121C
Altcode: 2014arXiv1402.5823C
Recent years have witnessed tremendous progress in our understanding
of the cosmos, which in turn points to even deeper questions to be
further addressed. Concurrently the laser technology has undergone
dramatic revolutions, providing exciting opportunity for science
applications. History has shown that the symbiosis between direct
observations and laboratory investigation is instrumental in the
progress of astrophysics. We believe that this remains true in
cosmology. Current frontier phenomena related to particle astrophysics
and cosmology typically involve one or more of the following conditions:
(1) extremely high energy events;(2) very high density, high temperature
processes; (3) super strong field environments. Laboratory experiments
using high intensity lasers can calibrate astrophysical observations,
investigate underlying dynamics of astrophysical phenomena, and probe
fundamental physics in extreme limits. In this article we give an
overview of the exciting prospect of laser cosmology. In particular,
we showcase its unique capability of investigating frontier cosmology
issues such as cosmic accelerator and quantum gravity.
Title: Variations of the 3-D coronal magnetic field associated with
the X3.4-class solar flare event of AR 10930
Authors: He, Han; Wang, Huaning; Yan, Yihua; Chen, P. F.; Fang, Cheng
Bibcode: 2014JGRA..119.3286H
Altcode: 2016arXiv160500367H
The variations of the 3-D coronal magnetic fields associated with the
X3.4-class flare of active region 10930 are studied in this paper. The
coronal magnetic field data are reconstructed from the photospheric
vector magnetograms obtained by the Hinode satellite and using the
nonlinear force-free field extrapolation method developed in our
previous work (He et al., 2011). The 3-D force-free factor α, 3-D
current density, and 3-D magnetic energy density are employed to analyze
the coronal data. The distributions of α and current density reveal
a prominent magnetic connectivity with strong negative α values and
strong current density before the flare. This magnetic connectivity
extends along the main polarity inversion line and is found to be
totally broken after the flare. The distribution variation of magnetic
energy density reveals the redistribution of magnetic energy before
and after the flare. In the lower space of the modeling volume the
increase of magnetic energy dominates, and in the higher space the
decrease of energy dominates. The comparison with the flare onset
imaging observation exhibits that the breaking site of the magnetic
connectivity and site with the highest values of energy density increase
coincide with the location of flare initial eruption. We conclude that
a cramped positive α region appearing in the photosphere causes the
breaking of the magnetic connectivity. A scenario for flare initial
eruption is proposed in which the Lorentz force acting on the isolated
electric current at the magnetic connectivity breaking site lifts the
associated plasmas and causes the initial ejection.
Title: Dependence of the length of solar filament threads on the
magnetic configuration
Authors: Zhou, Yu-Hao; Chen, Peng-Fei; Zhang, Qing-Min; Fang, Cheng
Bibcode: 2014RAA....14..581Z
Altcode: 2013arXiv1312.7181Z
High-resolution Hα observations indicate that filaments consist of
an assembly of thin threads. In quiescent filaments, the threads are
generally short, whereas in active region filaments, the threads are
generally long. In order to explain these observational features, we
performed one-dimensional radiative hydrodynamic simulations of filament
formation along a dipped magnetic flux tube in the framework of the
chromospheric evaporation-coronal condensation model. The geometry of
a dipped magnetic flux tube is characterized by three parameters, i.e.,
the depth (D), the half-width (w) and the altitude (h) of the magnetic
dip. A survey of the parameters in numerical simulations shows that
when allowing the filament thread to grow in 5 days, the maximum length
(Lth) of the filament thread increases linearly with w,
and decreases linearly with D and h. The dependence is fitted into a
linear function Lth = 0.84w - 0.88D - 2.78h+17.31(Mm). Such
a relation can qualitatively explain why quiescent filaments have
shorter threads and active region filaments have longer threads.
Title: Microwave Synthesis of Sugars
Authors: Barcena, H. S.; Chen, P.; Connolly, H. C.
Bibcode: 2014LPI....45.2459B
Altcode:
Microwave irradiation of ices of formaldehyde and calcium chloride
yielded sugars, which were studied by 2-D NMR spectroscopy.
Title: Imaging and Spectroscopic Observations of a Filament Channel
and the Implications for the Nature of Counter-streamings
Authors: Chen, P. F.; Harra, L. K.; Fang, C.
Bibcode: 2014ApJ...784...50C
Altcode: 2014arXiv1401.4514C
The dynamics of a filament channel are observed with imaging and
spectroscopic telescopes before and during the filament eruption on 2011
January 29. The extreme ultraviolet (EUV) spectral observations reveal
that there are no EUV counterparts of the Hα counter-streamings in the
filament channel, implying that the ubiquitous Hα counter-streamings
found by previous research are mainly due to longitudinal oscillations
of filament threads, which are not in phase between each other. However,
there exist larger-scale patchy counter-streamings in EUV along the
filament channel from one polarity to the other, implying that there
is another component of unidirectional flow (in the range of ±10
km s-1) inside each filament thread in addition to the
implied longitudinal oscillation. Our results suggest that the flow
direction of the larger-scale patchy counter-streaming plasma in the
EUV is related to the intensity of the plage or active network, with
the upflows being located at brighter areas of the plage and downflows
at the weaker areas. We propose a new method to determine the chirality
of an erupting filament on the basis of the skewness of the conjugate
filament drainage sites. This method suggests that the right-skewed
drainage corresponds to sinistral chirality, whereas the left-skewed
drainage corresponds to dextral chirality.
Title: Dielectric and magnetoelectric properties of
BaTiO3/γ-Fe2O3granular films
Authors: ZHAO, WenXi; SUN, Bai; LI, XiaoPeng; SHEN, Zhen; LIU,
YongHong; CHEN, Peng
Bibcode: 2014SSPMA..44..162Z
Altcode:
No abstract at ADS
Title: Automatic Detect and Trace of Solar Filaments
Authors: Fang, Cheng; Chen, P. F.; Tang, Yu-hua; Hao, Qi; Guo, Yang
Bibcode: 2014cosp...40E.835F
Altcode:
We developed a series of methods to automatically detect and trace
solar filaments in solar Hα images. The programs are able to not
only recognize filaments and determine their properties, such as the
position, the area and other relevant parameters, but also to trace
the daily evolution of the filaments. For solar full disk Hα images,
the method consists of three parts: first, preprocessing is applied
to correct the original images; second, the Canny edge-detection
method is used to detect the filaments; third, filament properties are
recognized through the morphological operators. For each Hα filament
and its barb features, we introduced the unweighted undirected graph
concept and adopted Dijkstra shortest-path algorithm to recognize the
filament spine; then, using polarity inversion line shift method for
measuring the polarities in both sides of the filament to determine
the filament axis chirality; finally, employing connected components
labeling method to identify the barbs and calculating the angle between
each barb and spine to indicate the barb chirality. Our algorithms are
applied to the observations from varied observatories, including the
Optical & Near Infrared Solar Eruption Tracer (ONSET) in Nanjing
University, Mauna Loa Solar Observatory (MLSO) and Big Bear Solar
Observatory (BBSO). The programs are demonstrated to be effective and
efficient. We used our method to automatically process and analyze
3470 images obtained by MLSO from January 1998 to December 2009,
and a butterfly diagram of filaments is obtained. It shows that the
latitudinal migration of solar filaments has three trends in the Solar
Cycle 23: The drift velocity was fast from 1998 to the solar maximum;
after the solar maximum, it became relatively slow and after 2006,
the migration became divergent, signifying the solar minimum. About
60% filaments with the latitudes larger than 50 degree migrate towards
the Polar Regions with relatively high velocities, and the latitudinal
migrating speeds in the northern and the southern hemispheres do not
differ significantly in the Solar Cycle 23. We also processed a number
of relatively high-resolution Hα images obtained by BBSO. It is found
that in some cases, the filament axis has single chirality and the
associated magnetic field also has single helicity, while its barbs
in different parts of it have opposite barb chirality.
Title: Concept and Analysis of a Satellite for Space-Based Radio
Detection of Ultra-High Energy Cosmic Rays
Authors: Romero-Wolf, Andrew; Gorham, P.; Booth, J.; Chen, P.; Duren,
R. M.; Liewer, K.; Nam, J.; Saltzberg, D.; Schoorlemmer, H.; Wissel,
S.; Zairfian, P.
Bibcode: 2014AAS...22321101R
Altcode:
We present a concept for on-orbit radio detection of ultra-high energy
cosmic rays (UHECRs) that has the potential to provide collection
rates of ~100 events per year for energies above 10^20 eV. The
synoptic wideband orbiting radio detector (SWORD) mission's high event
statistics at these energies combined with the pointing capabilities of
a space-borne antenna array could enable charged particle astronomy. The
detector concept is based on ANITA's successful detection UHECRs where
the geosynchrotron radio signal produced by the extended air shower
is reflected off the Earth's surface and detected in flight.
Title: Observations of MHD waves in the solar corona
Authors: Chen, P. F.
Bibcode: 2014cosp...40E.503C
Altcode:
In contrast to the MHD waves localized in the coronal loops,
which provide a useful diagnostic for the local magnetic field, the
global-scale MHD waves or wavelike propagating patterns can be used to
diagnose the large-scale magnetic field distribution and even magnetic
connectivity across the solar disk, which will pose an important
constraint for the ongoing global nonlinear force-free magnetic
extrapolation. In this review talk, I will summarize the observations
of various types of MHD waves and apparently propagating patterns. Their
applications to the coronal seismology will also be discussed shortly.
Title: Flux rope and CMEs: observations and modelings
Authors: Chen, P. F.
Bibcode: 2014cosp...40E.502C
Altcode:
Coronal mass ejections (CMEs) are the largest-scale eruptive phenomenon
in the solar atmosphere, which may pose hazardous threat to the space
weather near Earth. Therefore, it has attracted sustaining attention
among both solar and geophysical communities. Although not all CMEs
are observed to show the so-called three-component structure in the
coronagraph images, the derived physical paradigm based on the three
components seems to work well for most CMEs, i.e., most CMEs can be
described by erupting flux ropes. The remaining debates or unclear
issues include whether the embedded flux rope is formed before eruption
or during eruption, what is the relation between the three components
of a CME and the flux rope, what is the role of magnetic reconnection
in the acceleration and eruption of the CME, and so on. In this talk,
I review the observational evidence and modeling efforts in the
construction of the physical pattern of CMEs.
Title: A new multi-wavelength solar telescope: Optical and
Near-infrared Solar Eruption Tracer (ONSET)
Authors: Fang, Cheng; Chen, Peng-Fei; Li, Zhen; Ding, Ming-De; Dai,
Yu; Zhang, Xiao-Yu; Mao, Wei-Jun; Zhang, Jun-Ping; Li, Ting; Liang,
Yong-Jun; Lu, Hai-Tian
Bibcode: 2013RAA....13.1509F
Altcode: 2013arXiv1307.4533F
A new multi-wavelength solar telescope, the Optical and Near-infrared
Solar Eruption Tracer (ONSET) of Nanjing University, has been
constructed. It was fabricated at the Nanjing Institute of Astronomical
Optics & Technology, and the operation is jointly administered
with Yunnan Astronomical Observatory. ONSET is able to observe the Sun
in three wavelength windows: He I 10830 Å, Hα and white-light at
3600 Å and 4250 Å, which are selected in order to simultaneously
record the dynamics of the corona, chromosphere and photosphere
respectively. Full-disk or partial-disk solar images with a field of
10' at three wavelengths can be obtained nearly simultaneously. It
is designed to trace solar eruptions with high spatial and temporal
resolutions. This telescope was installed at a new solar observing
site near Fuxian Lake in Yunnan Province, southwest China. The site is
located at E102N24, with an altitude of 1722 m. The seeing is stable
and has high quality. We give a brief description of the scientific
objectives and the basic structure of ONSET. Some preliminary results
are also presented.
Title: Ultra-Fast Flash Observatory (uffo) for Observation of Early
Photons from Gamma Ray Bursts
Authors: Park, I. H.; Ahmad, S.; Barrillon, P.; Brandt, S.;
Budtz-Jorgensen, C.; Castro-Tirado, A. J.; Chen, P.; Choi, Y. J.;
Connell, P.; Dagoret-Campagne, S.; Eyles, C.; Grossan, B.; Huang,
M. -H. A.; Jung, A.; Jeong, S.; Kim, J. E.; Kim, M. B.; Kim, S. -W.;
Kim, Y. W.; Krasnov, A. S.; Lee1, J.; Lim, H.; Linder, E. V.; Liu,
T. -C.; Lund, N.; Min, K. W.; Na, G. W.; Nam, J. W.; Panasyuk, M. I.;
Ripa, J.; Reglero, V.; Rodrigo, J. M.; Smoot, G. F.; Suh, J. E.;
Svertilov, S.; Vedenkin, N.; Wang, M. -Z.; Yashin, I.
Bibcode: 2013tuuu.conf..259P
Altcode:
One of the least documented and understood aspects of gamma-ray
bursts (GRB) is the rise phase of the optical light curve. The
Ultra-Fast Flash Observatory (UFFO) is an effort to address this
question through extraordinary opportunities presented by a series
of space missions including a small spacecraft observatory. The UFFO
is equipped with a fast-response Slewing Mirror Telescope (SMT)
which uses rapidly moving mirror or mirror arrays to redirect the
optical beam rather than slewing the entire spacecraft to aim the
optical instrument at the GRB position. The UFFO will probe the early
optical rise of GRBs with a sub-second response, for the first time,
opening a completely new frontier in GRB and transient studies, the
only GRB system which can point and measure on these time scales. Its
fast response measurements of the optical emission of dozens of GRB
each year will provide unique probes of the burst mechanism, shock
breakouts in core-collapse supernovae, tidal disruptions around black
holes, test Lorentz violation, be the electromagnetic counterpart to
neutrino and gravitational wave signatures of the violent universe,
and verify the prospect of GRB as a new standard candle potentially
opening up the z>10 universe. As a first step, we employ a motorized
slewing stage in SMT which can point to the event within 1s after X-ray
trigger, in the UFFO-pathfinder payload onboard the Lomonosov satellite
to be launched in 2012. The pathfinder was a small and limited, yet
remarkably powerful micro-observatory for rapid optical response to
bright gamma-ray bursts, the first part of our GRB and rapid-response
long-term program. We describe the early photon science, the space
mission of UFFO-pathfinder, and our plan for the next step.
Title: The Uffo Slewing Mirror Telescope for Early Optical Observation
from Gamma Ray Bursts
Authors: Nam, Jiwoo; Ahmad, S.; Ahn, K.; Barrillon, P.; Brandt, S.;
Budtz-Jørgensen, C.; Castrotirado, A. J.; Chang, S. -H.; Chen, C. -R.;
Chen, P.; Choi, Y. J.; Connell, P.; Dagoret-Campagne, S.; Eyles, C.;
Grossan, B.; Huang, M. -H. A.; Huang, J. -J.; Jeong, S.; Jung, A.; Kim,
J. E.; Kim, S. H.; Kim, Y. W.; Lee, J.; Lim, H.; Lin, C. -Y.; Linder,
E. V.; Liu, T. -C.; Lund, N.; Min, K. W.; Na, G. W.; Panayuk, M. I.;
Park, I. H.; Ripa, J.; Reglero, V.; Rodrigo, J. M.; Smoot, G. F.;
Svertilov, S.; Vedenkin, N.; Wang, M. -Z.; Yashin, I.; Zhao, M. H.
Bibcode: 2013tuuu.conf..274N
Altcode:
While some space born observatories, such as SWIFT and FERMI, have been
operating, early observation of optical after grow of GRBs is still
remained as an unexplored region. The Ultra-Fast Flash Observatory
(UFFO) project is a space observatory for optical follow-ups of GRBs,
aiming to explore the first 60 seconds of GRBs optical emission. Using
fast moving mirrors to redirect our optical path rather than slewing
the entire spacecraft, UFFO is utilized to catch early optical emissions
from GRB within 1 sec. We have developed the UFFO Pathfinder Telescope
which is going to be on board of the Lomonosov satellite and launched
in middle of 2012. We will discuss about scientific potentials of the
UFFO project and present the payload development status, especially
for Slewing Mirror Telescope which is the key instrument of the
UFFO-pathfinder mission.
Title: Developing an Advanced Automated Method for Solar Filament
Recognition and Its Scientific Application to a Solar Cycle of MLSO
Hα Data
Authors: Hao, Q.; Fang, C.; Chen, P. F.
Bibcode: 2013SoPh..286..385H
Altcode: 2013arXiv1303.6367H
We developed a method to automatically detect and trace solar filaments
in Hα full-disk images. The program is able not only to recognize
filaments and determine their properties, such as the position, the
area, the spine, and other relevant parameters, but also to trace the
daily evolution of the filaments. The program consists of three steps:
First, preprocessing is applied to correct the original images; second,
the Canny edge-detection method is used to detect filaments; third,
filament properties are recognized through morphological operators. To
test the algorithm, we successfully applied it to observations from the
Mauna Loa Solar Observatory (MLSO). We analyzed Hα images obtained
by the MLSO from 1998 to 2009 and obtained a butterfly diagram
of filaments. This shows that the latitudinal migration of solar
filaments has three trends in Solar Cycle 23: The drift velocity was
fast from 1998 to the solar maximum, after which it became relatively
slow. After 2006, the migration became divergent, signifying the
solar minimum. About 60 % of the filaments with latitudes higher than
50∘ migrate toward the polar regions with relatively high
velocities, and the latitudinal migrating speeds in the northern and
the southern hemispheres do not differ significantly in Solar Cycle 23.
Title: Circulation Models of Close-In Exoplanet Atmospheres
Authors: Thrastarson, H. Th.; Cho, J. Y. -K.; Chen, P.
Bibcode: 2013EPSC....8.1045T
Altcode:
Many exoplanets, including those best suited for characterization, are
on close-in orbits and are likely tidally synchronized. Atmospheric
circulation affects the temperature distribution and thus transit
observations of these planets. In particular, hot spots shifted
by broad, steady, superrotating jets have been emphasized in the
literature. We present results from a general circulation model, solving
the primitive equations with thermal relaxation. The mini-Neptune
GJ1214b and hot Jupiter HD209458b are used as reference planets. We
explore a variety of conditions for forcing and initialization which
lead to different states. The resulting states have in common a low
number of jets, but large-scale vortices also play a big role and often
exhibit time variability (with corresponding variability in the position
of relative hot and cold regions). In contrast to many studies, we find
and explore cases where the equatorial jet can be westward as well as
eastward (superrotating) for tidally locked forcing conditions. For a
given forcing, varying initial conditions leads to different states,
but a given run also exhibits transitions between distinguishable
long-lasting (hundreds or thousands of planet rotations) states during
its long term evolution.
Title: A new ionospheric tomography model combining pixel-based and
function-based models
Authors: Yao, Yibin; Chen, Peng; Zhang, Shun; Chen, Jiajun
Bibcode: 2013AdSpR..52..614Y
Altcode:
Considering the limitations of current single pixel-based and
function-based computerized ionospheric tomography (CIT) models, this
paper proposes a new tomography model - COMBI, which combines these
two models. COMBI model is able to reconstruct the three dimensional
distribution of electron density with fewer parameters, and easy to
compute, as well as very convenient to use. Through experiments with
simulated data and measured data, it is verified that the new COMBI
model not only can better describe refine structure of ionospheric
electron density, but also is superior to these two pixel-based and
function-based CIT models in application.
Title: Status report of the UFFO-pathfinder
Authors: Huang, M. -H. A.; Park, I.; Ahmad, S.; Barrillon, P.; Brandt,
S.; Budtz-Jørgensen, C.; Castro-Tirado, A. J.; Chang, S. -H.;
Chang, Y. -Y.; Chen, C. -R.; Chen, P.; Choi, Y. J.; Connell, P.;
Dagoret-Campagne, S.; Eyles, C.; Grossan, B.; Jung, A.; Jeong, S.;
Huang, J. J.; Kim, J. E.; Kim, M. B.; Kim, S. W.; Kim, Y. W.; Krasnov,
A. S.; Lee, J.; Lim, H.; Lin, C. -Y.; Linder, E. V.; Liu, T. -C.; Lund,
N.; Min, K. W.; Na, G. W.; Nam, J. W.; Panasyuk, M. I.; Reglero, V.;
Ripa, J.; Rodrigo, J. M.; Smoot, G. F.; Suh, J. -E.; Svertilov, S.;
Vedenkin, N.; Wang, M. -Z.; Yashin, I.; UFFO Collaboration
Bibcode: 2013ICRC...33.1189H
Altcode: 2013ICRC...33..595H
Gamma-Ray Bursts (GRBs) are the most energetic explosions in the
universe, their optical photon flux rise very quickly, typically
within one minute, then fall off gradually. Hundreds of GRBs optical
light curves have been measured since the first discovery of GRB in
1967. However, only a handful of measurements have been made within
a minute after the gamma ray signal. Because of this drawback, the
short-hard type GRBs and rapid-rising GRBs, which may account for
30% of all GRBs, remain practically unexplored. To reach sub-minute
timescales, the Ultra-Fast Flash Observatory (UFFO) uses a rapidly
moving mirror to redirect the optical beam instead of slewing the entire
spacecraft. The first realization of this concept is UFFO-pathfinder,
which is equipped with fast-response Slewing Mirror Telescope (SMT)
and a UFFO Burst Alert and Trigger Telescope (UBAT). SMT has a slewing
mirror to redirect optical photons into a telescope and then record them
by an intensified CCD. UBAT uses coded mask to provide X-ray trigger
from a GRB and provides the GRB location for SMT. UFFOs sub-minute
measurements of the optical emission of dozens of GRBs each year
will result in a more rigorous test of current internal shock models,
probe the extremes of bulk Lorentz factors, provide the first early
and detailed measurements of fast-rise GRB optical light curves,
and help verify the prospect of GRB as a new standard candle. The
UFFO-pathfinder is fully integrated with the Lomonosov satellite and
is scheduled to be launched in late 2013 or early 2014. We will present
the latest progress in this conference.
Title: Ultra-Fast Flash Observatory: Fast Response Space Missions
for Early Time Phase of Gamma Ray Bursts
Authors: Park, I. H.; Ahmad, S.; Barrillon, P.; Brandt, S.;
Budtz-Jørgensen, C.; Castro-Tirado, A. J.; Chen, P.; Choi, J. N.;
Choi, Y. J.; Connell, P.; Dagoret-Campagne, S.; Eyles, C.; Grossan, B.;
Huang, M. -H. A. Huang; Jung, A.; Jeong, S.; Kim, J. E.; Kim, M. B.;
Kim, S. -W.; Kim, Y. W.; Krasnov, A. S.; Lee, J.; Lim, H.; Linder,
E. V.; Liu, T. -C.; Min, K. W.; Na, G. W.; Nam, J. W.; Panasyuk,
M. I.; Park, H. W.; Ripa, J.; Reglero, V.; Rodrigo, J. M.; Smoot,
G. F.; Svertilov, S.; Vedenkin, N.; Wang, M. -Z.; Yashin, I.
Bibcode: 2013EAS....61..501P
Altcode:
One of the unexplored domains in the study of gamma-ray bursts
(GRBs) is the early time phase of the optical light curve. We have
proposed Ultra-Fast Flash Observatory (UFFO) to address this question
through extraordinary opportunities presented by a series of small
space missions. The UFFO is equipped with a fast-response Slewing
Mirror Telescope that uses a rapidly moving mirror or mirror array to
redirect the optical beam rather than slewing the entire spacecraft or
telescope to aim the optical instrument at the GRB position. The UFFO
will probe the early optical rise of GRBs with sub-second response,
for the first time, opening a completely new frontier in GRB and
transient studies. Its fast response measurements of the optical
emission of dozens of GRB each year will provide unique probes of the
burst mechanism and test the prospect of GRB as a new standard candle,
potentially opening up the z > 10 universe. We describe the current
limit in early photon measurements, the aspects of early photon physics,
our soon-to-be-launched UFFO-pathfinder mission, and our next planned
mission, the UFFO-100.
Title: On the Prompt Signals of Gamma Ray Bursts
Authors: Chen, P.; Tajima, T.; Takahashi, Y.
Bibcode: 2013EAS....61...95C
Altcode: 2013arXiv1301.4523C
We introduce a new model of gamma ray burst (GRB) that explains
its observed prompt signals, namely, its primary quasi-thermal
spectrum and high energy tail. This mechanism can be applied to
either assumption of GRB progenitor: coalescence of compact objects
or hypernova explosion. The key ingredients of our model are: (1) The
initial stage of a GRB is in the form of a relativistic quark-gluon
plasma lava; (2) The expansion and cooling of this lava results in
a QCD phase transition that induces a sudden gravitational stoppage
of the condensed non-relativistic baryons and form a hadrosphere;
(3) Acoustic shocks and Alfven waves (magnetoquakes) that erupt
in episodes from the epicenter efficiently transport the thermal
energy to the hadrospheric surface and induce a rapid detachment
of leptons and photons from the hadrons; (4) The detached e +
e - and γ form an opaque, relativistically hot
leptosphere, which expands and cools to T ~ mc2, or 0.5
MeV, where e + e - → 2γ and its reverse
process becomes unbalanced, and the GRB photons are finally released;
(5) The mode-conversion of Alfven waves into electromagnetic waves in
the leptosphere provides a snowplow acceleration and deceleration that
gives rise to both the high energy spectrum of GRB and the erosion of
its thermal spectrum down to a quasi-thermal distribution. According
to this model, the observed GRB photons should have a redshifted
peak frequency at Ep ~ Γ(1 + β/2)mc2/(1 + z),
where Γ ~ O(1) is the Lorentz factor of the bulk flow of the lava,
which may be determined from the existing GRB data.
Title: Development of Slewing Mirror Telescope Optical System for
the UFFO-pathfinder
Authors: Jeong, S.; Nam, J. W.; Ahn, K. -B.; Park, I. H.; Kim, S. -W.;
Lee, J.; Lim, H.; Brandt, S.; Budtz-Jørgensen, C.; Castro-Tirado,
A. J.; Chen, P.; Cho, M. H.; Choi, J. N.; Grossan, B.; Huang, M. A.;
Jung, A.; Kim, J. E.; Kim, M. B.; Kim, Y. W.; Linder, E. V.; Min,
K. W.; Na, G. W.; Panasyuk, M. I.; Ripa, J.; Reglero, V.; Smoot,
G. F.; Suh, J. E.; Svertilov, S.; Vedenkin, N.; Yashin, I.
Bibcode: 2013EAS....61..561J
Altcode:
The Slewing Mirror Telescope (SMT) is the UV/optical telescope of
UFFO-pathfinder. The SMT optical system is a Ritchey-Chrétien (RC)
telescope of 100 mm diameter pointed by means of a gimbal-mounted
flat mirror in front of the telescope. The RC telescope has a 17 ×
17arcmin2 in Field of View and 4.3 arcsec resolution (full
width half maximum of the point spread function) The beam-steering
mirror enables the SMT to access a 35 × 35degree region and point
and settle within 1 sec. All mirrors were fabricated to about 0.02
wavelengths RMS in wave front error (WFE) and 84.7% average reflectivity
over 200 nm ~ 650 nm. The RC telescope was aligned to 0.05 wavelengths
RMS in WFE (test wavelength 632.8 nm). In this paper, the technical
details of the RC telescope and slewing mirror system assembly,
integration, and testing are given shortly, and performance tests of
the full SMT optical system are reported.
Title: Recent Development of Solar Observational Facilities in China
Authors: Fang, Cheng; Yan, Y.; Liu, Z.; Chen, P.
Bibcode: 2013SPD....4430301F
Altcode:
Since 1980’s, a series of solar telescopes in China has been put
into observations and got some useful data. After briefly introducing
these telescopes, we will mainly describe the development of solar
instruments in recent years. They are as follows: A Chinese Spectral
Radio Heliograph (CSRH) is constructing at Zheng xiang bai qi,
inner Mongolia. The frequency coverage is 0.4 - 15 GHz . The spatial
resolution is 1.3" - 50". The temporal resolution is better than
100 ms. CSRH has an array with 40 × 4.5 m plus 60 × 2 m parabolic
antennas. The largest base line is 3 km and the field of view is 0.5 -
7 degree. The low frequency part, CSRH-I, already got the first image
of the quiet Sun in Jan 2013. The high frequency part, CSRH-II, will be
finished in this year. A new 1 m vacuum solar telescope (NVST) has been
installed in 2010 at the observational base of YAO near the Fuxian lake,
which is 60 km away from Kunming. At present it is the best seeing place
in China. NVST aims at observing the sun in the range from 0.3 to 2.5
micron by high resolution imaging device and multi-wave spectrometers
combined with polarization analyzer. It has obtained high resolution
images at TiO, Hα and other wavelengths, as well as solar spectra in
optical and near infrared bands. A new telescope called ONSET (Optical
and NIR Solar Eruption Tracer) has been established at the observational
base of YAO in 2011. ONSET aims at studying the dynamics of flares and
small activities, CME onset and its source regions, coronal structures
and evolution, and white light flares. It consists of four tubes: (1)
a near-infrared vacuum tube with an aperture of 27.5 cm, working at He
I 10830±4.0Å with a FWHM of 0.5 Å (2) a chromospheric vacuum tube
with an aperture of 27.5 cm, working at 6562.8±2.5 Å with a FWHM
of 0.25 Å (3) a white-light vacuum tube with an aperture of 20 cm,
working at the wavelength 3600Å or 4250Å with a FWHM of 15 Å and
(4) a guiding tube. ONSET can provide simultaneously images of full or
partial disc (10 arcmin.) of the Sun at the three wavelengths of Hα
6563Å, 10830Å, and 3600Å or 4250Å. The preliminary observations
indicate that the image quality is quite good. ONSET has been put into
operation since 2013.
Title: In-Flight Calibrations of UFFO-Pathfinder
Authors: Řípa, J.; Ahmad, S.; Barrillon, P.; Brandt, S.;
Budtz-Jørgensen, C.; Castro-Tirado, A. J.; Chang, S. -H.; Chang,
Y. -Y.; Chen, C. R.; Chen, P.; Choi, H. S.; Choi, Y. J.; Connell,
P.; Dagoret-Campagne, S.; Eyles, C.; Grossan, B.; Huang, J. J.;
Huang, M. -H. A.; Jeong, S.; Jung, A.; Kim, J. -E.; Kim, M. -B.; Kim,
S. -W.; Kim, Y. -W.; Krasnov, A. S.; Lee, J.; Lim, H.; Lin, C. -Y.;
Linder, E. V.; Liu, T. -C.; Lund, N.; Min, K. W.; Na, G. -W.; Nam,
J. -W.; Panasyuk, M. I.; Park, I. H.; Reglero, V.; Rodrigo, J. M.;
Smoot, G. F.; Suh, J. -E.; Svertilov, S.; Vedenkin, N.; Wang, M. -Z.;
Yashin, I.
Bibcode: 2013EAS....61..579R
Altcode:
The Ultra-Fast Flash Observatory (UFFO), which will be launched onboard
the Lomonosov spacecraft, contains two crucial instruments: UFFO Burst
Alert & Trigger Telescope (UBAT) for detection and localization
of Gamma-Ray Bursts (GRBs) and the fast-response Slewing Mirror
Telescope (SMT) designed for the observation of the prompt optical/UV
counterparts. Here we discuss the in-space calibrations of the UBAT
detector and SMT telescope. After the launch, the observations of the
standard X-ray sources such as pulsar in Crab nebula will provide data
for necessary calibrations of UBAT. Several standard stars will be used
for the photometric calibration of SMT. The celestial X-ray sources,
e.g. X-ray binaries with bright optical sources in their close angular
vicinity will serve for the cross-calibration of UBAT and SMT.
Title: Readout of the UFFO Slewing Mirror Telescope to detect
UV/optical photons from Gamma-Ray Bursts
Authors: Kim, J. E.; Lim, H.; Nam, J. W.; Brandt, S.; Budtz-Jørgensen,
C.; Castro-Tirado, A. J.; Chen, P.; Choi, H. S.; Grossan, B.; Huang,
M. A.; Jeong, S.; Jung, A.; Kim, M. B.; Kim, S. -W.; Lee, J.; Linder,
E. V.; Liu, T. -C.; Na, G. W.; Panasyuk, M. I.; Park, I. H.; Ripa,
J.; Reglero, V.; Smoot, G. F.; Svertilov, S.; Vedenkin, N.; Yashin, I.
Bibcode: 2013JInst...8P7012K
Altcode:
The Slewing Mirror Telescope (SMT) was proposed for rapid response to
prompt UV/optical photons from Gamma-Ray Bursts (GRBs). The SMT is a
key component of the Ultra-Fast Flash Observatory (UFFO)-pathfinder,
which will be launched aboard the Lomonosov spacecraft at the end of
2013. The SMT utilizes a motorized mirror that slews rapidly forward
to its target within a second after triggering by an X-ray coded
mask camera, which makes unnecessary a reorientation of the entire
spacecraft. Subsequent measurement of the UV/optical is accomplished
by a 10 cm aperture Ritchey-Chrètien telescope and the focal plane
detector of Intensified Charge-Coupled Device (ICCD). The ICCD
is sensitive to UV/optical photons of 200-650 nm in wavelength by
using a UV-enhanced S20 photocathode and amplifies photoelectrons
at a gain of 104-106 in double Micro-Channel
Plates. These photons are read out by a Kodak KAI-0340 interline
CCD sensor and a CCD Signal Processor with 10-bit Analog-to-Digital
Converter. Various control clocks for CCD readout are implemented using
a Field Programmable Gate Array (FPGA). The SMT readout is in charge of
not only data acquisition, storage and transfer, but also control of the
slewing mirror, the ICCD high voltage adjustments, power distribution,
and system monitoring by interfacing to the UFFO-pathfinder. These
functions are realized in the FPGA to minimize power consumption and
to enhance processing time. The SMT readout electronics are designed
and built to meet the spacecraft's constraints of power consumption,
mass, and volume. The entire system is integrated with the SMT optics,
as is the UFFO-pathfinder. The system has been tested and satisfies the
conditions of launch and those of operation in space: those associated
with shock and vibration and those associated with thermal and vacuum,
respectively. In this paper, we present the SMT readout electronics:
the design, construction, and performance, as well as the results of
space environment test.
Title: Design and implementation of electronics and data acquisition
system for Ultra-Fast Flash Observatory
Authors: Jung, A.; Ahmad, S.; Barrillon, P.; Brandt, S.;
Budtz-Jørgensen, C.; Castro-Tirado, A. J.; Chang, S. -H.; Chang,
Y. -Y.; Chen, C. R.; Chen, P.; Choi, H. S.; Choi, Y. J.; Connell, P.;
Dagoret-Campagne, S.; Eyles, C.; Grossan, B.; Huang, J. J.; Huang,
M. -H. A.; Jeong, S.; Kim, J. E.; Kim, M.; Kim, S. -W.; Kim, Y. W.;
Krasnov, A. S.; Lee, J.; Lim, H.; Lin, C. -Y.; Linder, E. V.; Liu,
T. -C.; Lund, N.; Nam, J. W.; Min, K. W.; Na, G. W.; Panasyuk, M. I.;
Park, I. H.; Reglero, V.; Ripa, J.; Rodrigo, J. M.; Smoot, G. F.;
Suh, J. E.; Svertilov, S.; Vedenkin, N.; Wang, M. -Z.; Yashin, I.
Bibcode: 2013EAS....61..567J
Altcode:
The Ultra-Fast Flash Observatory (UFFO) Pathfinder for Gamma-Ray Bursts
(GRBs) consists of two telescopes. The UFFO Burst Alert & Trigger
Telescope (UBAT) handles the detection and localization of GRBs, and
the Slewing Mirror Telescope (SMT) conducts the measurement of the
UV/optical afterglow. UBAT is equipped with an X-ray detector, analog
and digital signal readout electronics that detects X-rays from GRBs
and determines the location. SMT is equipped with a stepping motor and
the associated electronics to rotate the slewing mirror targeting the
GRBs identified by UBAT. First the slewing mirror points to a GRB,
then SMT obtains the optical image of the GRB using the intensified
CCD and its readout electronics. The UFFO Data Acquisition system
(UDAQ) is responsible for the overall function and operation of the
observatory and the communication with the satellite main processor. In
this paper we present the design and implementation of the electronics
of UBAT and SMT as well as the architecture and implementation of UDAQ.
Title: The Calibration and Simulation of the GRB trigger detector
of the Ultra Fast Flash Observatory
Authors: Huang, M. -H. A.; Ahmad, S.; Barrillon, P.; Brandt, S.;
Budtz-Jørgensen, C.; Castro-Tirado, A. J.; Chang, S. -H.; Chang,
Y. -Y.; Chen, C. R.; Chen, P.; Choi, H. S.; Choi, Y. J.; Connell, P.;
Dagoret-Campagne, S.; Eyles, C.; Grossan, B.; Huang, J. J.; Jeong,
S.; Jung, A.; Kim, J. -E.; Kim, M. -B.; Kim, S. -W.; Kim, Y. -W.;
Krasnov, A. S.; Lee, J.; Lim, H.; Lin, C. -Y.; Linder, E. V.; Liu,
T. -C.; Lund, N.; Min, K. W.; Na, G. -W.; Nam, J. -W.; Panasyuk, M. I.;
Park, I. H.; Reglero, V.; Řípa, J.; Rodrigo, J. M.; Smoot, G. F.;
Suh, J. -E.; Svertilov, S.; Vedenkin, N.; Wang, M. -Z.; Yashin, I.
Bibcode: 2013EAS....61..531H
Altcode:
The UFFO (Ultra-Fast Flash Observatory) is a GRB detector on board
the Lomonosov satellite, to be launched in 2013. The GRB trigger is
provided by an X-ray detector, called UBAT (UFFO Burst Alarm &
Trigger Telescope), which detects X-rays from the GRB and then triggers
to determine the direction of the GRB and then alerts the Slewing
Mirror Telescope (SMT) to turn in the direction of the GRB and record
the optical photon fluxes. This report details the calibration of the
two components: the MAPMTs and the YSO crystals and simulations of
the UBAT. The results shows that this design can observe a GRB within
a field of view of ±35° and can trigger in a time scale as short as
0.2 - 1.0 s after the appearance of a GRB X-ray spike.
Title: Constraining GRB as Source for UHE Cosmic Rays through
Neutrino Observations
Authors: Chen, P.
Bibcode: 2013EAS....61..647C
Altcode: 2013arXiv1302.5319C
The origin of ultra-high energy cosmic rays (UHECR) has been widely
regarded as one of the major questions in the frontiers of particle
astrophysics. Gamma ray bursts (GRB), the most violent explosions
in the universe second only to the Big Bang, have been a popular
candidate site for UHECR productions. The recent IceCube report on
the non-observation of GRB induced neutrinos therefore attracts
wide attention. This dilemma requires a resolution: either the
assumption of GRB as UHECR accelerator is to be abandoned or the
expected GRB induced neutrino yield was wrong. It has been pointed
out that IceCube has overestimated the neutrino flux at GRB site by
a factor of ~5. In this paper we point out that, in addition to the
issue of neutrino production at source, the neutrino oscillation
and the possible neutrino decay during their flight from GRB to
Earth should further reduce the detectability of IceCube, which is
most sensitive to the muon-neutrino flavor as far as point-source
identification is concerned. Specifically, neutrino oscillation will
reduce the muon-neutrino flavor ratio from 2/3 per neutrino at GRB
source to 1/3 on Earth, while neutrino decay, if exists and under the
assumption of normal hierarchy of mass eigenstates, would result in a
further reduction of muon-neutrino ratio to 1/8. With these in mind,
we note that there have been efforts in recent years in pursuing other
type of neutrino telescopes based on Askaryan effect, which can in
principle observe and distinguish all three flavors with comparable
sensitivities. Such new approach may therefore be complementary to
IceCube in shedding more lights on this cosmic accelerator question.
Title: The Slewing Mirror Telescope and the Data-Acquisition System
for the UFFO-Pathfinder
Authors: Lim, H.; Ahmad, S.; Barrillon, P.; Brandt, S.;
Budtz-Jørgensen, C.; Castro-Tirado, A. J.; Chen, P.; Choi, Y. J.;
Connell, P.; Dagoret-Campagne, S.; Eyles, C.; Grossan, B.; Huang,
M. -H. A. Huang; Jung, A.; Jeong, S.; Kim, J. E.; Kim, M. B.; Kim,
S. -W.; Kim, Y. W.; Krasnov, A. S.; Lee, J.; Linder, E. V.; Liu,
T. -C.; Lund, N.; Min, K. W.; Na, G. W.; Nam, J. W.; Panasyuk, M. I.;
Park, I. H.; Ripa, J.; Reglero, V.; Rodrigo, J. M.; Smoot, G. F.;
Suh, J. E.; Svertilov, S.; Vedenkin, N.; Wang, M. -Z.; Yashin, I.
Bibcode: 2013EAS....61..537L
Altcode:
The Ultra-Fast Flash Observatory (UFFO) aims to detect the earliest
moment of Gamma-Ray Bursts (GRBs) which is not well known, resulting
into the enhancement of GRB mechanism understanding. The pathfinder
mission was proposed to be a scaled-down version of UFFO, and only
contains the UFFO Burst Alert & Trigger Telescope (UBAT) measuring
the X-ray/gamma-ray with the wide-field of view and the Slewing Mirror
Telescope (SMT) with a rapid-response for the UV/optical photons. Once
the UBAT detects a GRB candidate with the position accuracy of 10
arcmin, the SMT steers the UV/optical photons from the candidate to
the telescope by the fast rotatable mirror and provides the early
UV/optical photons measurements with 4 arcsec accuracy. The SMT has a
modified Ritchey-Chrètien telescope with the aperture size of 10 cm
diameter including the rotatable mirror and the image readout by the
intensified charge-coupled device. There is a key board called the
UFFO Data Acquisition system (UDAQ) that manages the communication
of each telescope and also of the satellite and the UFFO overall
operation. This pathfinder is designed and built within the limited
size and weight of ~20 kg and the low power consumption up to ~30
W. We will discuss the design and performance of the UFFO-pathfinder,
and its integration to the Lomonosov satellite.
Title: Design, Construction and Performance of the Detector for UFFO
Burst Alert & Trigger Telescope
Authors: Lee, J.; Jeong, S.; Kim, J. E.; Kim, Y. W.; Na, G. W.; Suh,
J. E.; Kim, M.; Lim, H.; Park, I. H.; Ripa, J.; Choi, J. N.; Kim,
S. -W.; Choi, Y. J.; Min, K. W.; Chen, P.; Huang, J. J.; Liu, T. -C.;
Nam, J. W.; Wang, M. -Z.; Huang, M. -H. A.; Connell, P.; Eyles, C.;
Reglero, V.; Rodrigo, J. M.; Castro-Tirado, A. J.
Bibcode: 2013EAS....61..525L
Altcode:
One of the key aspects of the upcoming Ultra-Fast Flash Observatory
(UFFO) pathfinder for Gamma Ray Bursts (GRBs) identification is the
UFFO Burst Alert & Trigger Telescope (UBAT). The scientific
propose of UBAT is to detect and locate as fast as possible the
GRBs in the sky. This is achieved by using a coded mask aperture
camera scheme with a wide field of view (FOV) and selecting a X-ray
detector of high quantum efficiency and large detection area. This
X-ray detector of high quantum efficiency and large detection area
is called the UBAT detector. The UBAT detector consists of 48 × 48
Yttrium Oxyorthosilicate (YSO) scintillator crystal arrays and Multi
Anode Photomultiplier Tubes (MAPMTs), analog electronics equipped
with ASIC chips, digital electronics equipped with Field Programmable
Gate Array (FPGA) chips, and a mechanical structure that supports
all components of the UBAT detector. The total number of the pixels
in the UBAT detector is 2304, and the total effective detection area
is 191 cm2. We will present the design and construction,
and performance of the UBAT detector including the responses of the
UBAT detector to X-ray sources.
Title: Development of Motorized Slewing Mirror Stage for the UFFO
Project
Authors: Nam, J.; Ahn, K. B.; Cho, M.; Jeong, S.; Kim, J. E.; Ahmad,
S.; Barrillon, P.; Brandt, S.; Budtz-Jørgensen, C.; Castro-Tirado,
A. J.; Chang, C. -H.; Chang, C. -Y.; Chang, Y. Y.; Chen, C. R.; Chen,
P.; Choi, H. S.; Choi, Y. J.; Connel, P.; Dagoret-Campagne, S.; Eyles,
C.; Grossan, B.; Huang, J. J.; Huang, M. -H. A.; Jung, A.; Kim, M. B.;
Kim, S. -W.; Kim, Y. W.; Krasnov, A. S.; Lee, J.; Lim, H.; Linder,
E. V.; Liu, T. -C.; Lund, N.; Min, K. W.; Na, G. W.; Panasyuk, M. I.;
Park, I. H.; Reglero, V.; Ripa, J.; Rodrigo, J. M.; Smoot, G. F.;
Suh, J. E.; Svertilov, S.; Vedenkin, N.; Wang, M. -Z.; Yashin, I.
Bibcode: 2013EAS....61..573N
Altcode:
The Ultra-Fast Flash Observatory (UFFO) is a space observatory for
optical follow-ups of gamma ray bursts (GRBs), aiming to explore
the first 60 seconds of GRBs optical emission. UFFO is utilized to
catch early optical emissions from GRBs within few sec after trigger
using a Gimbal mirror which redirects the optical path rather than
slewing entire spacecraft. We have developed a 15 cm two-axis Gimbal
mirror stage for the UFFO-Pathfinder which is going to be on board
the Lomonosov satellite which is to be launched in 2013. The stage is
designed for fast and accurate motion with given budgets of 3 kg of
mass and 3 Watt of power. By employing stepping motors, the slewing
mirror can rotate faster than 15 deg/sec so that objects in the UFFO
coverage (60 deg × 60 deg) can be targeted in ~1 sec. The obtained
targeting resolution is better 2 arcmin using a close-loop control
with high precision rotary encoder. In this presentation, we will
discuss details of design, manufacturing, space qualification tests,
as well as performance tests.
Title: Parametric survey of longitudinal prominence oscillation
simulations
Authors: Zhang, Q. M.; Chen, P. F.; Xia, C.; Keppens, R.; Ji, H. S.
Bibcode: 2013A&A...554A.124Z
Altcode: 2013arXiv1304.3798Z
Context. Longitudinal filament oscillations recently attracted
increasing attention, while the restoring force and the damping
mechanisms are still elusive.
Aims: We intend to investigate
the underlying physics for coherent longitudinal oscillations of the
entire filament body, including their triggering mechanism, dominant
restoring force, and damping mechanisms.
Methods: With the
MPI-AMRVAC code, we carried out radiative hydrodynamic numerical
simulations of the longitudinal prominence oscillations. We modeled
two types of perturbations of the prominence, impulsive heating at one
leg of the loop and an impulsive momentum deposition, which cause the
prominence to oscillate. We studied the resulting oscillations for a
large parameter scan, including the chromospheric heating duration,
initial velocity of the prominence, and field line geometry.
Results: We found that both microflare-sized impulsive heating at
one leg of the loop and a suddenly imposed velocity perturbation
can propel the prominence to oscillate along the magnetic dip. Our
extensive parameter survey resulted in a scaling law that shows that
the period of the oscillation, which weakly depends on the length and
height of the prominence and on the amplitude of the perturbations,
scales with √R/g⊙, where R represents the curvature
radius of the dip, and g⊙ is the gravitational acceleration
of the Sun. This is consistent with the linear theory of a pendulum,
which implies that the field-aligned component of gravity is the
main restoring force for the prominence longitudinal oscillations, as
confirmed by the force analysis. However, the gas pressure gradient
becomes significant for short prominences. The oscillation damps
with time in the presence of non-adiabatic processes. Radiative
cooling is the dominant factor leading to damping. A scaling law
for the damping timescale is derived, i.e., τ~ l1.63
D0.66w-1.21v0-0.30,
showing strong dependence on the prominence length l, the geometry
of the magnetic dip (characterized by the depth D and the width w),
and the velocity perturbation amplitude v0. The larger
the amplitude, the faster the oscillation damps. We also found that
mass drainage significantly reduces the damping timescale when the
perturbation is too strong.
Title: Massive Free-Streaming Neutrinos and Rise of Nν
at Recombination
Authors: Birrell, J.; Yang, C.; Chen, P.; Rafelski, J.
Bibcode: 2013APS..APR.B8008B
Altcode:
We present the Einstein-Vlasov solution for the momentum distribution
of the relic free-streaming neutrinos. We show that it is possible to
explain a rise in the effective number of neutrinos (Nν)
from those present at the end of big bang nucleosynthesis
(BBN) Nν(TBBN)=3.046 (theoretical) or
Nν(T BBN)=3.71^+0.47-0.45 (measured)
towards Nν(Tr)=4.34^+.086-0.88
(measured) at the time of electron-ion recombination (r). The effect
is due to the ambient temperature, Tr=0.253 eV, being
near to the neutrino mass. If a thermal equilibrium distribution is
inadvertently used, one instead expects a decrease in Nν
between BBN and recombination. We present explicit values for
mν needed to account for the observed increase in
Nν. The smaller the number of dominant mass neutrinos
and the larger the change in Nν needed between BBN and
recombination, the larger is the value of mν we find. If
no new mechanism is discovered to increase the theoretical value
Nν(TBBN)=3.046 then the relic neutrinos are
predicted to have 0.528<=∑mνi<=2.26
eV and will contribute between 5% and 22% of the matter inventory in
the Universe.
Title: Multiwavelength Study of a Solar Eruption from AR NOAA 11112:
II. Large-Scale Coronal Wave and Loop Oscillation
Authors: Kumar, Pankaj; Cho, K. -S.; Chen, P. F.; Bong, S. -C.;
Park, Sung-Hong
Bibcode: 2013SoPh..282..523K
Altcode: 2012arXiv1210.3417K
We analyze multiwavelength observations of an M2.9/1N flare that
occurred in AR NOAA 11112 on 16 October 2010. AIA 211 Å EUV images
reveal the presence of a faster coronal wave (decelerating from ≈
1390 to ≈ 830 km s−1) propagating ahead of a slower wave
(decelerating from ≈ 416 to ≈ 166 km s−1) towards
the western limb. The dynamic radio spectrum from Sagamore Hill
radio telescope shows the presence of a metric type II radio burst,
which reveals the presence of a coronal shock wave (speed ≈ 800 km
s−1). The speed of the faster coronal wave, derived from
AIA 211 Å images, is found to be comparable to the coronal shock
speed. AIA 171 Å high-cadence observations showed that a coronal
loop, which was located at a distance of ≈ 0.32R⊙ to
the west of the flaring region, started to oscillate by the end of
the impulsive phase of the flare. The results indicate that the faster
coronal wave may be the first driver of the transversal oscillations
of coronal loop. As the slower wave passed through the coronal loop,
the oscillations became even stronger. There was a plasmoid eruption
observed in EUV and a white-light CME was recorded, having velocity of
≈ 340 - 350 km s−1. STEREO 195 Å images show an EIT
wave, propagating in the same direction as the lower-speed coronal
wave observed in AIA, but decelerating from ≈ 320 to ≈ 254 km
s−1. These observations reveal the co-existence of both
waves (i.e. coronal Moreton and EIT waves), and the type II radio
burst seems to be associated with the coronal Moreton wave.
Title: Solar prominences: formation, force balance, internal dynamics
Authors: Keppens, R.; Xia, C.; Chen, P.; Blokland, J. W. S.
Bibcode: 2013ASPC..470...37K
Altcode:
Prominences represent fascinating large-scale, cool and dense
structures, suspended in the hot and tenuous solar corona above
magnetic neutral lines. Starting from magnetohydrostatic force
balance arguments, their differing magnetic topology distinguishes
Kippenhahn-Schlüter (1957) versus Kuperus-Raadu (1974) types. In both,
the concave-upward parts of magnetic field lines or ‘dips’ host
and support prominence material via the magnetic tension force against
gravity. We highlight recent insights into prominence physics, where we
start from modern magnetohydrodynamic equilibrium computations, allowing
to mimic flux-rope embedded multi-layer prominence configurations of
Kuperus-Raadu type. These can be analysed for linear stability, and
by quantifying the eigenfrequencies of flux-surface localized modes,
charting out the continuous parts of the MHD spectrum, we pave the way
for more detailed prominence seismology. Perhaps the most elusive aspect
of prominence physics is their sudden formation, and we demonstrate
recent achievements in both rigid field, and fully multi-dimensional
simulation efforts. The link with the thermal instability of
optically thin radiative plasmas is clarified, and we show the first
evaporation-condensation model study where we can demonstrate how the
formed prominence stays in a force balanced state, which can be compared
to the original Kippenhahn-Schlüter type magnetohydrostatic model.
Title: The Simulation Study of Kelvin Ship Wake for SAR Imaging
Authors: Gong, Biao; Chen, Peng; Zheng, Gang
Bibcode: 2013ESASP.704E..83G
Altcode:
In this paper, based on the Kelvin ship wake model, the sea surface
model, and Radar scattering model, we contrast the simulation of SAR
imaging by the same ship speed and different draft (4m, 6m and 8m). The
results shows that when ship speed is constant, the simulation of
Kelvin ship wake SAR imaging is not the same under different draft,
the deeper the draft, the clearer the transverse wave of Kelvin wake,
outside the range, the transverse wave can not be seen any longer.
Title: Slewing Mirror Telescope optics for the early observation of
UV/optical photons from Gamma-Ray Bursts
Authors: Jeong, S.; Nam, J. W.; Ahn, K. B.; Park, I. H.; Kim, S. W.;
Lee, J.; Lim, H.; Brandt, S.; Budtz-Jørgensen, C.; Castro-Tirado,
A. J.; Chen, P.; Cho, M. H.; Choi, J. N.; Grossan, B.; Huang, M. A.;
Jung, A.; Kim, J. E.; Kim, M. B.; Kim, Y. W.; Linder, E. V.; Min,
K. W.; Na, G. W.; Panasyuk, M. I.; Ripa, J.; Reglero, V.; Smoot,
G. F.; Suh, J. E.; Svertilov, S.; Vedenkin, N.; Yashin, I.
Bibcode: 2013OExpr..21.2263J
Altcode:
We report on design, manufacture, and testing of a Slewing Mirror
Telescope (SMT), the first of its kind and a part of Ultra-Fast Flash
Observatory-pathfinder (UFFO-p) for space-based prompt measurement of
early UV/optical light curves from Gamma-Ray Bursts (GRBs). Using a fast
slewing mirror of 150 mm diameter mounted on a 2 axis gimbal stage, SMT
can deliver the images of GRB optical counterparts to the intensified
CCD detector within 1.5-1.8 s over ± 35 degrees in the slewing field
of view. Its Ritchey-Chrétien telescope of 100 mm diameter provides
a 17 × 17 arcmin2 instantaneous field of view. Technical details
of design, construction, the laboratory performance tests in space
environments for this unique SMT are described in conjunction with
the plan for in-orbit operation onboard the Lomonosov satellite in 2013.
Title: Prominence formation and oscillations
Authors: Chen, P. F.
Bibcode: 2013ASInC..10....1C
Altcode: 2014arXiv1407.1413C
Prominences, or filaments, are a striking phenomenon in the solar
atmosphere. Besides their own rich features and dynamics, they are
related to many other activities, such as solar flares and coronal mass
ejections (CMEs). In the past several years we have been investigating
the prominence formation, oscillations, and eruptions through both
data analysis and radiative hydrodynamic and magnetohydrodynamic
(MHD) simulations. This paper reviews our progress on these topics,
which includes: (1) With updated radiative cooling function, the
coronal condensation becomes a little faster than previous work;
(2) Once a seed condensation is formed, it can grow via siphon flow
spontaneously even if the evaporation stops; (3) A scaling law was
obtained to relate the length of the prominence thread to various
parameters, indicating that higher prominences tend to have shorter
threads, which is consistent with the fact that threads are long
in active region prominences and short in quiescent prominences;
(4) It was proposed that long-time prominence oscillations out of
phase might serve as a precursor for prominence eruptions and CMEs;
(5) An ensemble of oscillating prominence threads may explain the
counter-streaming motion.
Title: Antarctic Radio Frequency Albedo and Implications for Cosmic
Ray Reconstruction
Authors: Besson, D. Z.; Stockham, J.; Sullivan, M.; Allison, P.;
Barwick, S. W.; Baughman, B. M.; Beatty, J. J.; Belov, K.; Bevan,
S.; Binns, W. R.; Chen, C.; Chen, P.; Clem, J. M.; Connolly, A.; De
Marco, D.; Dowkontt, P. F.; DuVernois, M.; Goldstein, D.; Gorham,
P. W.; Grashorn, E. W.; Hill, B.; Hoover, S.; Huang, M.; Israel,
M. H.; Javaid, A.; Kowalski, J.; Learned, J.; Liewer, K. M.; Matsuno,
S.; Mercurio, B. C.; Miki, C.; Mottram, M.; Nam, J.; Naudet, C. J.;
Nichol, R. J.; Palladino, K.; Romero-Wolf, A.; Ruckman, L.; Saltzberg,
D.; Seckel, D.; Shang, R. Y.; Stockham, M.; Varner, G. S.; Vieregg,
A. G.; Wang, Y.
Bibcode: 2013arXiv1301.4423B
Altcode:
From an elevation of ~38 km, the balloon-borne ANtarctic Impulsive
Transient Antenna (ANITA) is designed to detect the up-coming radio
frequency (RF) signal resulting from a sub-surface neutrino-nucleon
collision. Although no neutrinos have been discovered thus far,
ANITA is nevertheless the only experiment to self-trigger on radio
frequency emissions from cosmic-ray induced atmospheric air showers. In
the majority of those cases, down-coming RF signals are observed via
their reflection from the Antarctic ice sheet and back up to the ANITA
interferometer. Estimating the energy scale of the incident cosmic
rays therefore requires an estimate of the fractional power reflected
at the air-ice interface. Similarly, inferring the energy of neutrinos
interacting in-ice from observations of the upwards-directed signal
refracting out to ANITA also requires consideration of signal coherence
across the interface. By comparing the direct Solar RF signal intensity
measured with ANITA to the surface-reflected Solar signal intensity, as
a function of incident elevation angle relative to the surface {\Theta},
we estimate the power reflection coefficients R({\Theta}). We find
general consistency between our average measurements and the values
of R({\Theta}) expected from the Fresnel equations, separately for
horizontal- vs. vertical-polarizations.
Title: Carbon-based spintronics
Authors: Chen, Peng; Zhang, GuangYu
Bibcode: 2013SCPMA..56..207C
Altcode: 2013ScChG..56..207C
Carbon-based spintronics refers mainly to the spin injection and
transport in carbon materials including carbon nanotubes, graphene,
fullerene, and organic materials. In the last decade, extraordinary
development has been achieved for carbon-based spintronics, and the
spin transport has been studied in both local and nonlocal spin valve
devices. A series of theoretical and experimental studies have been done
to reveal the spin relaxation mechanisms and spin transport properties
in carbon materials, mostly for graphene and carbon nanotubes. In this
article, we provide a brief review on spin injection and transport in
graphene, carbon nanotubes, fullerene and organic thin films.
Title: Some Results from SAR and Optical Sensor Monitoring of
China Seas
Authors: Yang, Jingsong; Lou, Xiulin; Chen, Peng; Wang, Juan; Ren,
Lin; Chang, Junfang; Pan, Yufang
Bibcode: 2013ESASP.704E..25Y
Altcode:
As part of the final results of Dragon 2 Project Id. 5316
“Demonstrating SAR and optical sensor monitoring of Chinese Seas”,
some results from SAR and optical sensor monitoring of China Seas
including sea surface winds, ocean surface waves, typhoon and typhoon
waves, ocean internal waves, red tides, and ships are given in this
paper.
Title: The Uffo Slewing Mirror Telescope for Early Optical Observation
from Gamma Ray Bursts
Authors: Nam, Jiwoo; Ahmad, S.; Ahn, K.; Barrillon, P.; Brandt, S.;
Budtz-Jørgensen, C.; Castro-Tirado, A. J.; Chang, S. -H.; Chen,
C. -R.; Chen, P.; Choi, Y. J.; Connell, P.; Dagoret-Campagne, S.;
Eyles, C.; Grossan, B.; Huang, M. -H. A.; Huang, J. -J.; Jeong, S.;
Jung, A.; Kim, J. E.; Kim, S. H.; Kim, Y. W.; Lee, J.; Lim, H.; Lin,
C. -Y.; Linder, E. V.; Liu, T. -C.; Lund, N.; Min, K. W.; Na, G. W.;
Panayuk, M. I.; Park, I. H.; Ripa, J.; Reglero, V.; Rodrigo, J. M.;
Smoot, G. F.; Svertilov, S.; Vedenkin, N.; Wang, M. -Z.; Yashin, I.;
Zhao, M. H.
Bibcode: 2013MPLA...2840003N
Altcode:
While some space born observatories, such as SWIFT and FERMI, have been
operating, early observation of optical after grow of GRBs is still
remained as an unexplored region. The Ultra-Fast Flash Observatory
(UFFO) project is a space observatory for optical follow-ups of GRBs,
aiming to explore the first 60 seconds of GRBs optical emission. Using
fast moving mirrors to redirect our optical path rather than slewing
the entire spacecraft, UFFO is utilized to catch early optical emissions
from GRB within 1 sec. We have developed the UFFO Pathfinder Telescope
which is going to be on board of the Lomonosov satellite and launched
in middle of 2012. We will discuss about scientific potentials of the
UFFO project and present the payload development status, especially
for Slewing Mirror Telescope which is the key instrument of the
UFFO-pathfinder mission.
Title: Response of Photospheric Magnetic Fields to the Eruption of
Large Solar Flares
Authors: Yang, Y.; Chen, P.; He, H.
Bibcode: 2012AGUFMSH43B2168Y
Altcode:
The rapid and permanent changes in the photospheric magnetic fields
are regarded as the response to the coronal field reconfigurations
in solar flares. The magnitude of transverse magnetic field near
the flaring polarity inversion line is found to enhance after flares
together with the decrease of longitudinal field strength. It implies
that the flare-related magnetic fields become more horizontal after
the eruption of flares and can be explained by the back-reaction of
coronal fields. On the other hand, the magnetic shear of photospheric
field lines is found to increase after flares, which is contradictory
to the prediction of field relaxation due to flare energy release. To
characterize the changes of photospheric magnetic fields in flaring
active regions, the flare events with simultaneous hard X-ray (HXR)
and vector magnetogram observations are analyzed in this study. The
pre-flare and post-flare photospheric fields are obtained from SDO/HMI
or Hinode/SP vector magnetograms. The RHESSI HXR images are used to
identify the corresponding thermal and non-thermal HXR sources. The
spatial and temporal relationship between magnetic field and HXR
quantities will be discussed.
Title: General Circulation and Variability of Close-In Exoplanet
Atmospheres
Authors: Thrastarson, H. T.; Chen, P.
Bibcode: 2012AGUFM.P21B1846T
Altcode:
Many exoplanets are on close-in orbits and are likely tidally
synchronized. Scaling arguments and simulations indicate that this
type of planets may occupy a regime where atmospheric flow structures
(jets/vortices) are large, making their possible time variability
crucial to observations (if they are coupled to the temperature
field). Time variability affects assumptions when interpreting
observations, but also offers an opportunity to extract additional
information about the atmospheres from the time modulation of the
signals. The goal of our study is to constrain the conditions under
which time variability can be expected and understand mechanisms likely
to cause or quench variability on tidally locked exoplanets. We use
a general circulation model, solving the primitive equations with
thermal relaxation. We have explored the parameter space relevant
for tidally synchronized planets, using the mini-Neptune GJ1214b as
a reference planet. For a large range of conditions, robust features
include a small number of jets and large-scale vortices. The vortices
often exhibit time variability, associated with planetary scale waves,
with corresponding variability in the position of relative hot and cold
regions. These results make a strong case for mission concepts such
as NASA's FINESSE and ESA's EChO, that emphasize repeated measurements
of a given planet, enabling feedback between observations and modeling
that can yield new insights for exoplanet atmospheres. Furthermore, it
is already becoming possible to extract information about latitudinal
as well as longitudinal structure of transiting exoplanet atmospheres,
so knowledge about the extent of spatial and temporal variability can
soon be within reach.
Title: Quadrature Observations of Wave and Non-wave Components and
their Decoupling in an Extreme-ultraviolet Wave Event
Authors: Dai, Y.; Ding, M. D.; Chen, P. F.; Zhang, J.
Bibcode: 2012ApJ...759...55D
Altcode: 2012arXiv1208.4539D
We report quadrature observations of an extreme-ultraviolet (EUV) wave
event on 2011 January 27 obtained by the Extreme Ultraviolet Imager on
board the Solar Terrestrial Relations Observatory, and the Atmospheric
Imaging Assembly on board the Solar Dynamics Observatory. Two
components are revealed in the EUV wave event. A primary front is
launched with an initial speed of ~440 km s-1. It appears
that significant emission enhancement occurs in the hotter channel
while deep emission reduction occurs in the cooler channel. When the
primary front encounters a large coronal loop system and slows down,
a secondary, much fainter, front emanates from the primary front with a
relatively higher starting speed of ~550 km s-1. Afterward,
the two fronts propagate independently with increasing separation. The
primary front finally stops at a magnetic separatrix, while the
secondary front travels farther until it fades out. In addition,
upon the arrival of the secondary front, transverse oscillations of
a prominence are triggered. We suggest that the two components are
of different natures. The primary front belongs to a non-wave coronal
mass ejection (CME) component, which can be reasonably explained with
the field-line stretching model. The multi-temperature behavior may be
caused by considerable heating due to nonlinear adiabatic compression
on the CME frontal loop. As for the secondary front, it is most likely
a linear fast-mode magnetohydrodynamic wave that propagates through
a medium of the typical coronal temperature. X-ray and radio data
provide us with complementary evidence in support of the above scenario.
Title: Implications of ultrahigh energy neutrino flux constraints
for Lorentz-invariance violating cosmogenic neutrinos
Authors: Gorham, P. W.; Connolly, A.; Allison, P.; Beatty, J. J.;
Belov, K.; Besson, D. Z.; Binns, W. R.; Chen, P.; Clem, J. M.; Hoover,
S.; Israel, M. H.; Nam, J.; Saltzberg, D.; Varner, G. S.; Vieregg,
A. G.
Bibcode: 2012PhRvD..86j3006G
Altcode: 2012arXiv1207.6425G
We consider the implications of Lorentz-invariance violation (LIV)
on cosmogenic neutrino observations, with particular focus on the
constraints imposed on several well-developed models for ultrahigh
energy cosmogenic neutrino production by recent results from the ANITA
long-duration balloon payload, and RICE at the South Pole. Under
a scenario proposed originally by Coleman and Glashow, each lepton
family may attain maximum velocities that can exceed c, leading to
energy-loss through several interaction channels during propagation. We
show that future observations of cosmogenic neutrinos will provide
by far the most stringent limit on LIV in the neutrino sector. We
derive the implied level of LIV required to suppress observation of
predicted fluxes from several mainstream cosmogenic neutrino models,
and specifically those recently constrained by the ANITA and RICE
experiments. We simulate via detailed Monte Carlo code the propagation
of cosmogenic neutrino fluxes in the presence of LIV-induced energy
losses. We show that this process produces several detectable effects
in the resulting attenuated neutrino spectra, even at LIV-induced
neutrino superluminality of (uν-c)/c≃10-26,
about 13 orders of magnitude below current bounds.
Title: General Circulation and Variability of Close-In Exoplanet
Atmospheres
Authors: Thrastarson, H. T.; Chen, P.
Bibcode: 2012epsc.conf..795T
Altcode: 2012espc.conf..795T
Many exoplanets are on close-in orbits and are likely tidally
synchronized. Scaling arguments and simulations indicate that this
type of planets may occupy a regime where atmospheric flow structures
(jets/vortices) are large, making their possible time variability
crucial to observations (if they are coupled to the temperature
field). Time variability affects assumptions when interpreting
observations, but also offers an opportunity to extract additional
information about the atmospheres from the time modulation of the
signals. The goal of our study is to constrain the conditions under
which time variability can be expected and understand mechanisms likely
to cause or quench variability on tidally locked exoplanets. We use
a general circulation model, solving the primitive equations with
thermal relaxation. We have explored the parameter space relevant
for tidally synchronized planets, using the super-Earth GJ1214b as
a reference planet. For a large range of conditions, robust features
include a small number of jets and largescale vortices. The vortices
often exhibit time variability, associated with planetary scale waves,
with corresponding variability in the position of relative hot and cold
regions. These results make a strong case for mission concepts such
as NASA's FINESSE and ESA's EChO, that emphasize repeated measurements
of a given planet, enabling feedback between observations and modeling
that can yield new insights for exoplanet atmospheres. Furthermore, it
is already becoming possible to extract information about latitudinal
as well as longitudinal structure of transiting exoplanet atmospheres,
so knowledge about the extent of spatial and temporal variability can
soon be within reach.
Title: Ultra-Fast Flash Observatory for observation of early photons
from gamma ray bursts
Authors: Park, I. H.; Ahmad, S.; Barrillon, P.; Brandt, S.;
Budtz-Jørgensen, C.; Castro-Tirado, A. J.; Chen, P.; Choi, Y. J.;
Connell, P.; Dagoret-Campagne, S.; Eyles, C.; Grossan, B.; Huang,
M. -H. A.; Jeong, S.; Jung, A.; Kim, J. E.; Kim, M. B.; Kim, S. -W.;
Kim, Y. W.; Krasnov, A. S.; Lee, J.; Lim, H.; Linder, E. V.; Liu,
T. -C.; Lund, N.; Min, K. W.; Na, G. W.; Nam, J. W.; Panasyuk, M. I.;
Ripa, J.; Reglero, V.; Rodrigo, J. M.; Smoot, G. F.; Suh, J. E.;
Svertilov, S.; Vedenkin, N.; Wang, M. -Z.; Yashin, I.
Bibcode: 2012SPIE.8443E..0IP
Altcode:
We describe the space project of Ultra-Fast Flash Observatory (UFFO)
which will observe early optical photons from gamma-ray bursts (GRBs)
with a sub-second optical response, for the first time. The UFFO
will probe the early optical rise of GRBs, opening a completely new
frontier in GRB and transient studies, using a fast response Slewing
Mirror Telescope (SMT) that redirects optical path to telescope instead
of slewing of telescopes or spacecraft. In our small UFFO-Pathfinder
experiment, scheduled to launch aboard the Lomonosov satellite in 2012,
we use a motorized mirror in our Slewing Mirror Telescope instrument to
achieve less than one second optical response after X-ray trigger. We
describe the science and the mission of the UFFO project, including a
next version called UFFO-100. With our program of ultra-fast optical
response GRB observatories, we aim to gain a deeper understanding of
GRB mechanisms, and potentially open up the z<10 universe to study
via GRB as point source emission probes.
Title: A next generation Ultra-Fast Flash Observatory (UFFO-100)
for IR/optical observations of the rise phase of gamma-ray bursts
Authors: Grossan, B.; Park, I. H.; Ahmad, S.; Ahn, K. B.; Barrillon,
P.; Brandt, S.; Budtz-Jørgensen, C.; Castro-Tirado, A. J.; Chen,
P.; Choi, H. S.; Choi, Y. J.; Connell, P.; Dagoret-Campagne, S.;
De La Taille, C.; Eyles, C.; Hermann, I.; Huang, M. -H. A.; Jung,
A.; Jeong, S.; Kim, J. E.; Kim, M.; Kim, S. -W.; Kim, Y. W.; Lee,
J.; Lim, H.; Linder, E. V.; Liu, T. -C.; Lund, N.; Min, K. W.; Na,
G. W.; Nam, J. W.; Panasyuk, M. I.; Ripa, J.; Reglero, V.; Rodrigo,
J. M.; Smoot, G. F.; Suh, J. E.; Svertilov, S.; Vedenkin, N.; Wang,
M. -Z.; Yashin, I.; Zhao, M. H.
Bibcode: 2012SPIE.8443E..2RG
Altcode: 2012arXiv1207.5759G
The Swift Gamma-ray Burst (GRB) observatory responds to GRB triggers
with optical observations in ~ 100 s, butcannot respond faster
than ~ 60 s. While some rapid-response ground-based telescopes
have responded quickly, thenumber of sub-60 s detections remains
small. In 2013 June, the Ultra-Fast Flash Observatory-Pathfinder is
expected tobe launched on the Lomonosov spacecraft to investigate
early optical GRB emission. Though possessing uniquecapability for
optical rapid-response, this pathfinder mission is necessarily limited
in sensitivity and event rate; here wediscuss the next generation of
rapid-response space observatory instruments. We list science topics
motivating ourinstruments, those that require rapid optical-IR GRB
response, including: A survey of GRB rise shapes/times,measurements
of optical bulk Lorentz factors, investigation of magnetic dominated
(vs. non-magnetic) jet models,internal vs. external shock origin
of prompt optical emission, the use of GRBs for cosmology, and dust
evaporation inthe GRB environment. We also address the impacts of the
characteristics of GRB observing on our instrument andobservatory
design. We describe our instrument designs and choices for a next
generation space observatory as a secondinstrument on a low-earth
orbit spacecraft, with a 120 kg instrument mass budget. Restricted
to relatively modest mass,power, and launch resources, we find that a
coded mask X-ray camera with 1024 cm2 of detector area could
rapidlylocate about 64 GRB triggers/year. Responding to the locations
from the X-ray camera, a 30 cm aperture telescope witha beam-steering
system for rapid (~ 1 s) response and a near-IR camera should detect ~
29 GRB, given Swift GRBproperties. The additional optical camera would
permit the measurement of a broadband optical-IR slope, allowingbetter
characterization of the emission, and dynamic measurement of dust
extinction at the source, for the first time.
Title: The Ultra-Fast Flash Observatory's space GRB mission and
science
Authors: Lim, H.; Ahmad, S.; Barrillon, P.; Blin-Bondil, S.; Brandt,
S.; Budtz-Jørgensen, C.; Castro-Tirado, A. J.; Chen, P.; Choi,
H. S.; Choi, Y. J.; Connell, P.; Dagoret-Campagne, S.; De La Taille,
C.; Eyles, C.; Grossan, B.; Hermann, I.; Huang, M. -H. A.; Jeong,
S.; Jung, A.; Kim, J. E.; Kim, S. -W.; Kim, Y. W.; Lee, J.; Linder,
E. V.; Liu, T. -C.; Lund, N.; Min, K. W.; Na, G. W.; Nam, J. W.;
Nam, K. H.; Panasyuk, M. I.; Park, I. H.; Reglero, V.; Řípa, J.;
Rodrigo, J. M.; Smoot, G. F.; Svetilov, S.; Vedenkin, N.; Yashin, I.
Bibcode: 2012IAUS..279..349L
Altcode:
The Ultra-Fast Flash Observatory (UFFO) is a space mission to detect
the early moments of an explosion from Gamma-ray bursts (GRBs), thus
enhancing our understanding of the GRB mechanism. It consists of the
UFFO Burst & Trigger telescope (UBAT) for the recognition of GRB
positions using hard X-ray from GRBs. It also contains the Slewing
Mirror Telescope (SMT) for the fast detection of UV-optical photons
from GRBs. It is designed to begin the UV-optical observations in
less than a few seconds after the trigger. The UBAT is based on a
coded-mask X-ray camera with a wide field of view (FOV) and is composed
of the coded mask, a hopper and a detector module. The SMT has a fast
rotatable mirror which allows a fast UV-optical detection after the
trigger. The telescope is a modified Ritchey-Chrétien telescope with
the aperture size of 10 cm diameter, and an image intensifier readout
by CCD. The UFFO pathfinder is scheduled to launch into orbit on 2012
June by the Lomonosov spacecraft. It is a scaled-down version of UFFO
in order to make the first systematic study of early UV/optical light
curves, including the rise phase of GRBs. We expect UBAT to trigger
~44 GRBs/yr and expect SMT to detect ~10 GRBs/yr.
Title: The readout system and the trigger algorithm implementation
for the UFFO Pathfinder
Authors: Na, G. W.; Ahmad, S.; Barrillon, P.; Brandt, S.;
Budtz-Jørgensen, C.; Castro-Tirado, A. J.; Chen, P.; Choi, Y. J.;
Connell, P.; Dagoret-Campagne, S.; Eyles, C.; Grossan, B.; Huang,
M. -H. A.; Jeong, S.; Jung, A.; Kim, J. E.; Kim, M. B.; Kim, S. -W.;
Kim, Y. W.; Krasnov, Aleksey S.; Lee, J.; Lim, H.; Linder, E. V.;
Liu, T. -C.; Lund, N.; Min, K. W.; Nam, J. W.; Park, I. H.; Panasyuk,
M. I.; Ripa, J.; Reglero, V.; Rodrigo, J. M.; Smoot, G. F.; Suh,
J. E.; Svertilov, S.; Vedenkin, N.; Wang, M. -Z.; Yashin, I.
Bibcode: 2012SPIE.8443E..2TN
Altcode:
Since the launch of the SWIFT, Gamma-Ray Bursts (GRBs) science has
been much progressed. Especially supporting many measurements of
GRB events and sharing them with other telescopes by the Gamma-ray
Coordinate Network (GCN) have resulted the richness of GRB events,
however, only a few of GRB events have been measured within a minute
after the gamma ray signal. This lack of sub-minute data limits
the study for the characteristics of the UV-optical light curve of
the short-hard type GRB and the fast-rising GRB. Therefore, we have
developed the telescope named the Ultra-Fast Flash Observatory (UFFO)
Pathfinder, to take the sub-minute data for the early photons from
GRB. The UFFO Pathfinder has a coded-mask X-ray camera to search the
GRB location by the UBAT trigger algorithm. To determine the direction
of GRB as soon as possible it requires the fast processing. We have
ultimately implemented all algorithms in field programmable gate arrays
(FPGA) without microprocessor. Although FPGA, when compared with
microprocessor, is generally estimated to support the fast processing
rather than the complex processing, we have developed the implementation
to overcome the disadvantage and to maximize the advantage. That is
to measure the location as accurate as possible and to determine the
location within the sub-second timescale. In the particular case for
a accuracy of the X-ray trigger, it requires special information from
the satellite based on the UFFO central control system. We present the
implementation of the UBAT trigger algorithm as well as the readout
system of the UFFO Pathfinder.
Title: Design and implementation of the UFFO burst alert and trigger
telescope
Authors: Kim, J. E.; Ahmad, S.; Barrillon, P.; Brandt, S.;
Budtz-Jørgensen, C.; Castro-Tirado, A. J.; Chen, P.; Choi, Y. J.;
Connell, P.; Dagoret-Campagne, S.; Eyles, C.; Grossan, B.; Huang,
M. -H. A.; Jung, A.; Jeong, S.; Kim, M. B.; Kim, S. -W.; Kim, Y. W.;
Krasnov, A. S.; Lee, J.; Lim, H.; Linder, E. V.; Liu, T. -C.; Lund,
N.; Min, K. W.; Na, G. W.; Nam, J. W.; Panasyuk, M. I.; Park, I. H.;
Ripa, J.; Reglero, V.; Rodrigo, J. M.; Smoot, G. F.; Suh, J. E.;
Svertilov, S.; Vedenkin, N.; Wang, M. -Z.; Yashin, I.
Bibcode: 2012SPIE.8443E..2VK
Altcode:
The Ultra Fast Flash Observatory pathfinder (UFFO-p) is a telescope
system designed for the detection of the prompt optical/UV photons
from Gamma-Ray Bursts (GRBs), and it will be launched onboard the
Lomonosov spacecraft in 2012. The UFFO-p consists of two instruments:
the UFFO Burst Alert and Trigger telescope (UBAT) for the detection and
location of GRBs, and the Slewing Mirror Telescope (SMT) for measurement
of the UV/optical afterglow. The UBAT isa coded-mask aperture X-ray
camera with a wide field of view (FOV) of 1.8 sr. The detector module
consists of the YSO(Yttrium Oxyorthosilicate) scintillator crystal
array, a grid of 36 multi-anode photomultipliers (MAPMTs), and analog
and digital readout electronics. When the γ /X-ray photons hit the YSO
scintillator crystal array, it produces UV photons by scintillation in
proportion to the energy of the incident γ /X-ray photons. The UBAT
detects X-ray source of GRB inthe 5 ~ 100 keV energy range, localizes
the GRB within 10 arcmin, and sends the SMT this information as well
as drift correction in real time. All the process is controlled by a
Field Programmable Gates Arrays (FPGA) to reduce the processing time. We
are in the final stages of the development and expect to deliver the
instrument for the integration with the spacecraft. In what follows
we present the design, fabrication and performance test of the UBAT.
Title: The slewing mirror telescope of the Ultra Fast Flash
Observatory Pathfinder
Authors: Jeong, S.; Ahmad, S.; Barrillon, P.; Brandt, S.;
Budtz-Jørgensen, C.; Castro-Tirado, A. J.; Chen, P.; Choi, Y. J.;
Connell, P.; Dagoret-Campagne, S.; Eyles, C.; Grossan, B.; Huang,
M. -H. A.; Jung, A.; Kim, J. E.; Kim, M. B.; Kim, S. -W.; Kim, Y. W.;
Krasnov, A. S.; Lee, J.; Lim, H.; Linder, E. V.; Liu, T. -C.; Lund,
N.; Min, K. W.; Na, G. W.; Nam, J. W.; Park, I. H.; Panasyuk, M. I.;
Ripa, J.; Reglero, V.; Rodrigo, J. M.; Smoot, G. F.; Suh, J. E.;
Svertilov, S.; Vedenkin, N.; Wang, M. -Z.; Yashin, I.; Ahn, K. -B.
Bibcode: 2012SPIE.8443E..2SJ
Altcode:
The Slewing Mirror Telescope (SMT) is a key telescope of Ultra-Fast
Flash Observatory (UFFO) space project to explore the first sub-minute
or sub-seconds early photons from the Gamma Ray Bursts (GRBs)
afterglows. As the realization of UFFO, 20kg of UFFO-Pathfinder
(UFFO-P) is going to be on board the Russian Lomonosov satellite
in November 2012 by Soyuz-2 rocket. Once the UFFO Burst Alert &
Trigger Telescope (UBAT) detects the GRBs, Slewing mirror (SM) will slew
to bring new GRB into the SMT’s field of view rather than slewing
the entire spacecraft. SMT can give a UV/Optical counterpart position
rather moderated 4arcsec accuracy. However it will provide a important
understanding of the GRB mechanism by measuring the sub-minute optical
photons from GRBs. SMT can respond to the trigger over 35 degree x 35
degree wide field of view within 1 sec by using Slewing Mirror Stage
(SMS). SMT is the reflecting telescope with 10cm Ritchey-Chretien type
and 256 x 256 pixilated Intensified Charge-Coupled Device (ICCD). In
this paper, we discuss the overall design of UFFO-P SMT instrument
and payloads development status.
Title: A new MHD code with adaptive mesh refinement and
parallelization for astrophysics
Authors: Jiang, R. -L.; Fang, C.; Chen, P. -F.
Bibcode: 2012CoPhC.183.1617J
Altcode: 2012arXiv1204.5849J
A new code, named MAP, is written in FORTRAN language for
magnetohydrodynamics (MHD) simulations with the adaptive mesh refinement
(AMR) and Message Passing Interface (MPI) parallelization. There
are several optional numerical schemes for computing the MHD part,
namely, modified Mac Cormack Scheme (MMC), Lax-Friedrichs scheme
(LF), and weighted essentially non-oscillatory (WENO) scheme. All of
them are second-order, two-step, component-wise schemes for hyperbolic
conservative equations. The total variation diminishing (TVD) limiters
and approximate Riemann solvers are also equipped. A high resolution can
be achieved by the hierarchical block-structured AMR mesh. We use the
extended generalized Lagrange multiplier (EGLM) MHD equations to reduce
the non-divergence free error produced by the scheme in the magnetic
induction equation. The numerical algorithms for the non-ideal terms,
e.g., the resistivity and the thermal conduction, are also equipped
in the code. The details of the AMR and MPI algorithms are described
in the paper.
Title: Toward a Better Standard Model for Solar Flares
Authors: Chen, P. F.
Bibcode: 2012ASPC..454..265C
Altcode:
Multiwavelength observations were pieced together to construct the
standard reconnection model for two-ribbon flares in the 1960s-1970s,
which has set up a framework for understanding the flare and the
associated mass ejections. As flares were observed with higher and
higher resolutions, accumulating new features have been revealed,
which are not expected from the standard model, such as the 3D
structures, the kinematics of the flare loop, and the dynamics of
the plasma along the flare loop. These challenging features, however,
enable us to improve the standard magnetic reconnection model, which
would then become more realistic to the solar atmosphere. In addition,
the formation of the frontal loop of coronal mass ejections (CMEs)
was not well addressed in the standard model. It has been illusive
whether the frontal loop is an erupting flux tube or plasma pileup
swept by waves. Recent observations shed crucial light on this key
issue. In this review paper, I collect the challenging features and
comment on how they can be incorporated into the standard model.
Title: The growth and properties of an m-plane InN epilayer on
LiAlO2 (100) by metal-organic chemical vapor deposition
Authors: Xie, ZiLi; Zhang, Rong; Fu, DeYi; Liu, Bin; Xiu, XiangQian;
Hua, XueMei; Zhao, Hong; Chen, Peng; Han, Ping; Shi, Yi; Zheng, YouDou
Bibcode: 2012SCPMA..55.1249X
Altcode: 2012ScChG..55.1249X
The m-plane InN (1 bar 1 00) epilayers have been grown on a
LiAlO2 (1 0 0) substrate by a two-step growth method
using a metal-organic chemical vapor deposition (MOCVD) system. The
low temperature InN buffer layer (LT-InN) is introduced to overcome
the drawbacks of thermal instability of LiAlO2 (LAO) and
to relieve the strains due to a large thermal mismatch between LAO
and InN. Then the high temperature m-plane InN (1 bar 1 00) epilayers
(HT-InN) were grown. The results of X-ray diffraction (XRD) suggest that
the m-plane InN (1 bar 1 00) epilayer is a single crystal. The X-ray
rocking curves ( ω scans) (XRC) and atomic force microscopy (AFM)
indicate that the m-plane InN (1 bar 1 00) epilayer has anisotropic
crystallographic properties. The PL studies of the materials reveal
a remarkable energy band gap structure around 0.70 eV at 15 K.
Title: Observations and simulations of longitudinal oscillations of
an active region prominence
Authors: Zhang, Q. M.; Chen, P. F.; Xia, C.; Keppens, R.
Bibcode: 2012A&A...542A..52Z
Altcode: 2012arXiv1204.3787Z
Context. Filament longitudinal oscillations have been observed
in Hα observations of the solar disk.
Aims: We intend to
find an example of the longitudinal oscillations of a prominence,
where the magnetic dip can be seen directly, and examine the
restoring force of this type of oscillations.
Methods:
We carry out a multiwavelength data analysis of the active region
prominence oscillations above the western limb on 2007 February
8. In addition, we perform a one-dimensional hydrodynamic simulation
of the longitudinal oscillations.
Results: Our analysis of
high-resolution observations performed by Hinode/SOT indicate that the
prominence, seen as a concave-inward shape in lower-resolution extreme
ultraviolet (EUV) images, consists of many concave-outward threads,
which is indicative of magnetic dips. After being injected into the dip
region, a bulk of prominence material started to oscillate for more
than 3.5 h, with the period of 52 min. The oscillation decayed with
time, on the decay timescale 133 min. Our hydrodynamic simulation
can reproduce the oscillation period, but the damping timescale
in the simulation is 1.5 times as long as the observations.
Conclusions: The results clearly show the prominence longitudinal
oscillations around the dip of the prominence and our study suggests
that the restoring force of the longitudinal oscillations might be the
gravity. Radiation and heat conduction are insufficient to explain the
decay of the oscillations. Other mechanisms, such as wave leakage and
mass accretion, have to be considered. The possible relation between
the longitudinal oscillations and the later eruption of a prominence
thread, as well as a coronal mass ejection (CME), is also discussed.
Title: ONSET-A New Multi-Wavelength Solar Telescope
Authors: Fang, C.; Chen, P. F.; Ding, M. D.; Dai, Y.; Li, Z.
Bibcode: 2012EAS....55..349F
Altcode:
A new multi-wavelength solar telescope, Optical and Near-infrared
Solar Eruption Tracer (ONSET), is constructed by Nanjing University,
being run in cooperation with Yunnan Astronomical Observatory. ONSET
is able to observe the Sun in three wavelength windows: He I 10830 Å,
Hα and white-light at 3600 Å or 4250 Å. Full-disk or partial solar
images with a field of 10 arcmin at three wavelengths can be obtained
nearly simultaneously. It is designed to trace solar eruptions with high
spatial and temporal resolutions. This telescope has been installed at
a new solar observing site near the Fuxian Lake, Yunnan Province. The
site is located at E102N24, with an altitude of 1722 m. The seeing is
stable and very nice. We give a brief description of the scientific
objectives and the basic structure of ONSET. Some preliminary results
are also shown.
Title: Magnetic Reconnection in a Canopy-type Magnetic Configuration
for Solar Microflares
Authors: Jiang, R. -L.; Fang, C.; Chen, P. -F.
Bibcode: 2012EAS....55..107J
Altcode:
We performed 2.5D compressible resistive MHD simulations of magnetic
reconnection with gravity considered. The background magnetic field
is a canopy-type configuration which is rooted at the boundary of the
solar supergranule. By changing the bottom boundary conditions in the
simulations, an emerging flux rises up at the center of the supergranule
and reconnects with the canopy magnetic field. We successfully simulate
the coronal and chromospheric microflares, whose current sheets locate
at the corona and chromosphere respectively. The coronal microflare is
triggered by the reconnection at the corona, whose size and temperature
enhancement is bigger and higher than the chromospheric one. We also
found a hot jet (~1.8 × 106 K) relating to the observational
EUV/SXR jet and a cold jet (~104 K) corresponding to the
observational Hα/Ca surge or brightening in the coronal case. Whereas
there is only Hα/Ca bright point in the chromospheric one.
Title: Development of a single board microwave sub-system based on
substrate integrated waveguide (SIW) technology
Authors: Chen, Jixin; Hong, Wei; Hao, Zhangcheng; Yan, Pinpin; Zhu,
Xiaowei; Zhou, Jianyi; Chen, Peng; Wu, Ke
Bibcode: 2012imsd.conf59473C
Altcode:
No abstract at ADS
Title: Numerical Simulation of Solar Microflares in a Canopy-type
Magnetic Configuration
Authors: Jiang, R. -L.; Fang, C.; Chen, P. -F.
Bibcode: 2012ApJ...751..152J
Altcode: 2012arXiv1204.5847J
Microflares are small activities in the solar low atmosphere; some are
in the low corona while others are in the chromosphere. Observations
show that some of the microflares are triggered by magnetic
reconnection between the emerging flux and a pre-existing background
magnetic field. We perform 2.5-dimensional, compressible, resistive
magnetohydrodynamic simulations of the magnetic reconnection
with gravity considered. The background magnetic field is a
canopy-type configuration that is rooted at the boundary of the
solar supergranule. By changing the bottom boundary conditions in
the simulation, a new magnetic flux emerges at the center of the
supergranule and reconnects with the canopy-type magnetic field. We
successfully simulate the coronal and chromospheric microflares
whose current sheets are located at the corona and the chromosphere,
respectively. The microflare with a coronal origin has a larger
size and a higher temperature enhancement than the microflare with a
chromospheric origin. In the microflares with coronal origins, we also
found a hot jet (~1.8 × 106 K), which is probably related
to the observational extreme ultraviolet or soft X-ray jets, and a cold
jet (~104 K), which is similar to the observational Hα/Ca
surges. However, there is only a Hα/Ca bright point in the microflares
that have chromospheric origins. The study of parameter dependence
shows that the size and strength of the emerging magnetic flux are the
key parameters that determine the height of the reconnection location,
and they further determine the different observational features of
the microflares.
Title: A Converging View on EIT Waves
Authors: Chen, P. F.; Fang, C.
Bibcode: 2012EAS....55..313C
Altcode:
Coronal "EIT wave" is a large-scale wavelike phenomenon propagating
across the major part of the Sun. Debates are being continued regarding
a more suitable name for it, its source driver, and its nature. "EIT
waves" have been widely explained in terms of fast-mode waves, despite
that the model contradicts with many observational features. Two-types
of EUV waves were predicted 10 years ago. With the recent high-cadence
observations, mainly from SDO/AIA telescope, more and more evidence
has been revealed in favor of the two-wave model. In this paper, after
summarizing different names used for EIT waves in the literature,
we show how the community are getting close to reaching a consensus
on the nature of EIT waves.
Title: Simulations of Prominence Formation in the Magnetized Solar
Corona by Chromospheric Heating
Authors: Xia, C.; Chen, P. F.; Keppens, R.
Bibcode: 2012ApJ...748L..26X
Altcode: 2012arXiv1202.6185X
Starting from a realistically sheared magnetic arcade connecting the
chromospheric, transition region to coronal plasma, we simulate the
in situ formation and sustained growth of a quiescent prominence in
the solar corona. Contrary to previous works, our model captures all
phases of the prominence formation, including the loss of thermal
equilibrium, its successive growth in height and width to macroscopic
dimensions, and the gradual bending of the arched loops into dipped
loops, as a result of the mass accumulation. Our 2.5 dimensional,
fully thermodynamically and magnetohydrodynamically consistent model
mimics the magnetic topology of normal-polarity prominences above a
photospheric neutral line, and results in a curtain-like prominence
above the neutral line through which the ultimately dipped magnetic
field lines protrude at a finite angle. The formation results from
concentrated heating in the chromosphere, followed by plasma evaporation
and later rapid condensation in the corona due to thermal instability,
as verified by linear instability criteria. Concentrated heating
in the lower atmosphere evaporates plasma from below to accumulate
at the top of coronal loops and supply mass to the later prominence
constantly. This is the first evaporation-condensation model study
where we can demonstrate how the formed prominence stays in a force
balanced state, which can be compared to the Kippenhahn-Schlüter type
magnetohydrostatic model, all in a finite low-beta corona.
Title: Two Types of Magnetic Reconnection in Coronal Bright Points
and the Corresponding Magnetic Configuration
Authors: Zhang, Q. M.; Chen, P. F.; Guo, Y.; Fang, C.; Ding, M. D.
Bibcode: 2012ApJ...746...19Z
Altcode:
Coronal bright points (CBPs) are long-lived small-scale brightenings
in the solar corona. They are generally explained by magnetic
reconnection. However, the corresponding magnetic configurations are
not well understood. We carry out a detailed multi-wavelength analysis
of two neighboring CBPs on 2007 March 16, observed in soft X-ray
(SXR) and EUV channels. It is seen that the SXR light curves present
quasi-periodic flashes with an interval of ~1 hr superposed over the
long-lived mild brightenings, suggesting that the SXR brightenings of
this type of CBPs might consist of two components: one is the gentle
brightenings and the other is the CBP flashes. It is found that the
strong flashes of the bigger CBP are always accompanied by SXR jets. The
potential field extrapolation indicates that both CBPs are covered by
a dome-like separatrix surface, with a magnetic null point above. We
propose that the repetitive CBP flashes, as well as the recurrent SXR
jets, result from the impulsive null-point reconnection, while the
long-lived brightenings are due to the interchange reconnection along
the separatrix surface. Although the EUV images at high-temperature
lines resemble the SXR appearance, the 171 Å and 195 Å channels
reveal that the blurry CBP in SXR consists of a cusp-shaped loop and
several separate bright patches, which are explained to be due to the
null-point reconnection and the separatrix reconnection, respectively.
Title: Erratum: Observational constraints on the ultrahigh energy
cosmic neutrino flux from the second flight of the ANITA experiment
[Phys. Rev. D 82 022004 (2010)]
Authors: Gorham, P. W.; Allison, P.; Baughman, B. M.; Beatty, J. J.;
Belov, K.; Besson, D. Z.; Bevan, S.; Binns, W. R.; Chen, C.; Chen,
P.; Clem, J. M.; Connolly, A.; Detrixhe, M.; de Marco, D.; Dowkontt,
P. F.; Duvernois, M.; Grashorn, E. W.; Hill, B.; Hoover, S.; Huang,
M.; Israel, M. H.; Javaid, A.; Liewer, K. M.; Matsuno, S.; Mercurio,
B. C.; Miki, C.; Mottram, M.; Nam, J.; Nichol, R. J.; Palladino, K.;
Romero-Wolf, A.; Ruckman, L.; Saltzberg, D.; Seckel, D.; Shang, R. Y.;
Varner, G. S.; Vieregg, A. G.; Wang, Y.
Bibcode: 2012PhRvD..85d9901G
Altcode:
No abstract at ADS
Title: Design and initial performance of the Askaryan Radio Array
prototype EeV neutrino detector at the South Pole
Authors: Ara Collaboration; Allison, P.; Auffenberg, J.; Bard,
R.; Beatty, J. J.; Besson, D. Z.; Böser, S.; Chen, C.; Chen, P.;
Connolly, A.; Davies, J.; Duvernois, M.; Fox, B.; Gorham, P. W.;
Grashorn, E. W.; Hanson, K.; Haugen, J.; Helbing, K.; Hill, B.;
Hoffman, K. D.; Hong, E.; Huang, M.; Huang, M. H. A.; Ishihara, A.;
Karle, A.; Kennedy, D.; Landsman, H.; Liu, T. C.; Macchiarulo, L.;
Mase, K.; Meures, T.; Meyhandan, R.; Miki, C.; Morse, R.; Newcomb,
M.; Nichol, R. J.; Ratzlaff, K.; Richman, M.; Ritter, L.; Rott, C.;
Rotter, B.; Sandstrom, P.; Seckel, D.; Touart, J.; Varner, G. S.;
Wang, M. -Z.; Weaver, C.; Wendorff, A.; Yoshida, S.; Young, R.
Bibcode: 2012APh....35..457A
Altcode: 2011arXiv1105.2854A
We report on studies of the viability and sensitivity of the Askaryan
Radio Array (ARA), a new initiative to develop a Teraton-scale
ultra-high energy neutrino detector in deep, radio-transparent ice
near Amundsen-Scott station at the South Pole. An initial prototype ARA
detector system was installed in January 2011, and has been operating
continuously since then. We describe measurements of the background
radio noise levels, the radio clarity of the ice, and the estimated
sensitivity of the planned ARA array given these results, based on
the first five months of operation. Anthropogenic radio interference
in the vicinity of the South Pole currently leads to a few-percent
loss of data, but no overall effect on the background noise levels,
which are dominated by the thermal noise floor of the cold polar ice,
and galactic noise at lower frequencies. We have also successfully
detected signals originating from a 2.5 km deep impulse generator
at a distance of over 3 km from our prototype detector, confirming
prior estimates of kilometer-scale attenuation lengths for cold polar
ice. These are also the first such measurements for propagation over
such large slant distances in ice. Based on these data, ARA-37, the
∼200 km2 array now in its initial construction phase, will
achieve the highest sensitivity of any planned or existing neutrino
detector in the 1016-1019 eV energy range.
Title: Where do flare ribbons stop?
Authors: Chen, P. F.; Su, J. T.; Guo, Y.; Deng, Y. Y.
Bibcode: 2012ChSBu..57.1393C
Altcode: 2011arXiv1109.0381C
The standard flare model, which was proposed based on observations and
magnetohydrodynamic theory, can successfully explain many observational
features of solar flares. However, this model is just a framework,
with many details awaiting to be filled in, including how reconnection
is triggered. In this paper, we address an unanswered question: where
do flare ribbons stop? With the data analysis of the 2003 May 29 flare
event, we tentatively confirmed our conjecture that flare ribbons
finally stop at the intersection of separatrices (or quasi-separatrix
layer in a general case) with the solar surface. Once verified, such a
conjecture can be used to predict the final size and even the lifetime
of solar flares.
Title: Weak ferromagnetism of HfOxfilms deposited by sputtering in
different depositing/annealing ambient
Authors: Zhou, GuangDong; Chen, XianFeng; Tu, YaTing; Zhang, ShouYing;
Liu, ZhiJiang; Li, Jian; Chen, Peng; Qiu, XiaoYan
Bibcode: 2012SSPMA..42..926Z
Altcode:
No abstract at ADS
Title: Exoplanet Spectroscopy: The Hubble Case
Authors: Deroo, P.; Swain, M.; Vasisht, G.; Chen, P.; Tinetti, G.;
Bouwman, J.; Angerhausen, D.; Yung, Y.
Bibcode: 2011ASPC..450...63D
Altcode:
The Hubble Space Telescope has recently emerged as the first
telescope to detect molecular signatures in an exoplanet via infrared
spectroscopy. Molecular spectroscopy of exoplanets is demanding
and requires an accurate determination and removal of the instrument
systematics. Here we report on our effort to extract accurate exoplanet
spectra from NICMOS spectrophotometry. We developed a standardized
and highly automated pipeline to remove instrument systematics based
on our previous results. We tested the pipeline and find excellent
agreement with observation specific implementations. The process of
decorrelating instrument parameters from the measured time series is
well understood, stable and guarantees reproducible results.
Title: On the design of experiments for the study of extreme field
limits in the interaction of laser with ultrarelativistic electron
beam
Authors: Bulanov, S. V.; Esirkepov, T. Zh.; Hayashi, Y.; Kando,
M.; Kiriyama, H.; Koga, J. K.; Kondo, K.; Kotaki, H.; Pirozhkov,
A. S.; Bulanov, S. S.; Zhidkov, A. G.; Chen, P.; Neely, D.; Kato,
Y.; Narozhny, N. B.; Korn, G.
Bibcode: 2011NIMPA.660...31B
Altcode: 2011arXiv1101.2501B
We propose the experiments on the collision of laser light and high
intensity electromagnetic pulses generated by relativistic flying
mirrors, with electron bunches produced by a conventional accelerator
and with laser wake field accelerated electrons for studying extreme
field limits in the nonlinear interaction of electromagnetic waves. The
regimes of dominant radiation reaction, which completely changes
the electromagnetic wave-matter interaction, will be revealed in the
laser plasma experiments. This will result in a new powerful source
of ultra short high brightness gamma-ray pulses. A possibility of
the demonstration of the electron-positron pair creation in vacuum
in a multi-photon processes can be realized. This will allow modeling
under terrestrial laboratory conditions neutron star magnetospheres,
cosmological gamma ray bursts and the Leptonic Era of the Universe.
Title: Spectroscopic Analysis of Interaction between an
Extreme-ultraviolet Imaging Telescope Wave and a Coronal Upflow Region
Authors: Chen, F.; Ding, M. D.; Chen, P. F.; Harra, L. K.
Bibcode: 2011ApJ...740..116C
Altcode: 2011arXiv1107.5630C
We report a spectroscopic analysis of an EUV Imaging Telescope (EIT)
wave event that occurred in active region 11081 on 2010 June 12 and
was associated with an M2.0 class flare. The wave propagated nearly
circularly. The southeastern part of the wave front passed over an
upflow region near a magnetic bipole. Using EUV Imaging Spectrometer
raster observations for this region, we studied the properties of
plasma dynamics in the wave front, as well as the interaction between
the wave and the upflow region. We found a weak blueshift for the
Fe XII λ195.12 and Fe XIII λ202.04 lines in the wave front. The
local velocity along the solar surface, which is deduced from the
line-of-sight velocity in the wave front and the projection effect,
is much lower than the typical propagation speed of the wave. A more
interesting finding is that the upflow and non-thermal velocities
in the upflow region are suddenly diminished after the transit of
the wave front. This implies a significant change of magnetic field
orientation when the wave passed. As the lines in the upflow region
are redirected, the velocity along the line of sight is diminished
as a result. We suggest that this scenario is more in accordance with
what was proposed in the field-line stretching model of EIT waves.
Title: Formation of Solar Filaments by Steady and Nonsteady
Chromospheric Heating
Authors: Xia, C.; Chen, P. F.; Keppens, R.; van Marle, A. J.
Bibcode: 2011ApJ...737...27X
Altcode: 2011arXiv1106.0094X
It has been established that cold plasma condensations can form in a
magnetic loop subject to localized heating of its footpoints. In this
paper, we use grid-adaptive numerical simulations of the radiative
hydrodynamic equations to investigate the filament formation process
in a pre-shaped loop with both steady and finite-time chromospheric
heating. Compared to previous works, we consider low-lying
loops with shallow dips and use a more realistic description for
radiative losses. We demonstrate for the first time that the onset of
thermal instability satisfies the linear instability criterion. The
onset time of the condensation is roughly ~2 hr or more after the
localized heating at the footpoint is effective, and the growth rate
of the thread length varies from 800 km hr-1 to 4000 km
hr-1, depending on the amplitude and the decay length scale
characterizing this localized chromospheric heating. We show how single
or multiple condensation segments may form in the coronal portion. In
the asymmetric heating case, when two segments form, they approach
and coalesce, and the coalesced condensation later drains down into
the chromosphere. With steady heating, this process repeats with a
periodicity of several hours. While our parametric survey confirms and
augments earlier findings, we also point out that steady heating is not
necessary to sustain the condensation. Once the condensation is formed,
it keeps growing even after the localized heating ceases. In such a
finite-heating case, the condensation instability is maintained by
chromospheric plasma that gets continuously siphoned into the filament
thread due to the reduced gas pressure in the corona. Finally, we
show that the condensation can survive the continuous buffeting of
perturbations from photospheric p-mode waves.
Title: The First Limits on the Ultra-high Energy Neutrino Fluence
from Gamma-Ray Bursts
Authors: Vieregg, A. G.; Palladino, K.; Allison, P.; Baughman, B. M.;
Beatty, J. J.; Belov, K.; Besson, D. Z.; Bevan, S.; Binns, W. R.;
Chen, C.; Chen, P.; Clem, J. M.; Connolly, A.; Detrixhe, M.; De Marco,
D.; Dowkontt, P. F.; DuVernois, M.; Gorham, P. W.; Grashorn, E. W.;
Hill, B.; Hoover, S.; Huang, M.; Israel, M. H.; Javaid, A.; Liewer,
K. M.; Matsuno, S.; Mercurio, B. C.; Miki, C.; Mottram, M.; Nam, J.;
Nichol, R. J.; Romero-Wolf, A.; Ruckman, L.; Saltzberg, D.; Seckel,
D.; Varner, G. S.; Wang, Y.
Bibcode: 2011ApJ...736...50V
Altcode: 2011arXiv1102.3206V
We set the first limits on the ultra-high energy (UHE) neutrino fluence
at energies greater than 109 GeV from gamma-ray bursts
(GRBs) based on data from the second flight of the Antarctic Impulsive
Transient Antenna (ANITA). During the 31 day flight of ANITA-II,
26 GRBs were recorded by Swift or Fermi. Of these, we analyzed the
12 GRBs which occurred during quiet periods when the payload was
away from anthropogenic activity. In a blind analysis, we observe 0
events on a total background of 0.0044 events in the combined prompt
window for all 12 low-background bursts. We also observe 0 events
from the remaining 14 bursts. We place a 90% confidence level limit
on the E -4 prompt neutrino fluence between 108
GeV < E < 1012 GeV of E 4Φ = 2.5 ×
1017 GeV3 cm-2 from GRB090107A. This
is the first reported limit on the UHE neutrino fluence from GRBs above
109 GeV, and the strongest limit above 108 GeV.
Title: First Evidence of Coexisting EIT Wave and Coronal Moreton
Wave from SDO/AIA Observations
Authors: Chen, P. F.; Wu, Y.
Bibcode: 2011ApJ...732L..20C
Altcode: 2011arXiv1103.0871C
"EIT waves" are a globally propagating wavelike phenomenon. They were
often interpreted as fast-mode magnetoacoustic waves in the corona,
despite various discrepancies between the fast-mode wave model and
observations. To reconcile these discrepancies, we suggested that "EIT
waves" are the apparent propagation of the plasma compression due to
successive stretching of the magnetic field lines pushed by the erupting
flux rope. According to this model, an EIT wave should be preceded
by a fast-mode wave, which, however, had rarely been observed. With
the unprecedented high cadence and sensitivity of the Solar Dynamics
Observatory observations, we discern a fast-moving wave front with
a speed of 560 km s-1 ahead of an EIT wave, which had a
velocity of ~190 km s-1, in the "EIT wave" event on 2010
July 27. The results, suggesting that "EIT waves" are not fast-mode
waves, confirm the prediction of our field-line stretching model for
an EIT wave. In particular, it is found that the coronal Moreton wave
was ~3 times faster than the EIT wave, as predicted.
Title: Coronal Mass Ejections: Models and Their Observational Basis
Authors: Chen, P. F.
Bibcode: 2011LRSP....8....1C
Altcode:
Coronal mass ejections (CMEs) are the largest-scale eruptive phenomenon
in the solar system, expanding from active region-sized nonpotential
magnetic structure to a much larger size. The bulk of plasma with a mass
of ∼ 1011,1013 kg is hauled up all the way out
to the interplanetary space with a typical velocity of several hundred
or even more than 1000 km s-1, with a chance to impact our
Earth, resulting in hazardous space weather conditions. They involve
many other much smaller-sized solar eruptive phenomena, such as X-ray
sigmoids, filament/prominence eruptions, solar flares, plasma heating
and radiation, particle acceleration, EIT waves, EUV dimmings, Moreton
waves, solar radio bursts, and so on. It is believed that, by shedding
the accumulating magnetic energy and helicity, they complete the last
link in the chain of the cycling of the solar magnetic field. In this
review, I try to explicate our understanding on each stage of the
fantastic phenomenon, including their pre-eruption structure, their
triggering mechanisms and the precursors indicating the initiation
process, their acceleration and propagation. Particular attention is
paid to clarify some hot debates, e.g., whether magnetic reconnection
is necessary for the eruption, whether there are two types of CMEs,
how the CME frontal loop is formed, and whether halo CMEs are special.
Title: Case Studies of Ship Classification from SAR Data Based on
Polarimetric Scattering Characteristics
Authors: Yang, Jingsong; Wang, Juan; Chen, Peng; Xiao, Qingmei
Bibcode: 2011ESASP.695E..78Y
Altcode:
Case studies of ship classification from NASA Jet Propulsion
Laboratory (JPL) AIRSAR and NASA SIR-C synthetic aperture radar (SAR)
fully polarimetric data are presented in this paper. Four steps are
carried out: (1) the sketches of ships are obtained by using edge
detection and mathematical morphology approaches; (2) the polarimetric
scattering characteristics of each pixel is obtained by using 6 target
decomposition methods such as Pauli, Sphere-Dihedral-Helix (SDH),
Surface-Double Bounce-Volume (SDBV), Moriyama, four-component, and
Cameron decomposition; (3) scattering types of each pixel are merged
into 4 types from the results of different decomposition methods;
(4) ships are then classified into 6 types (sphere scattering
dominant, dihedral scattering dominant, volume scattering dominant,
sphere-dihedral scattering dominant, sphere-volume scattering dominant
and mixed type).
Title: The inversion of the real kinematic properties of coronal
mass ejections by forward modeling
Authors: Wu, You; Chen, Peng-Fei
Bibcode: 2011RAA....11..237W
Altcode: 2010arXiv1010.0409W
Kinematic properties of coronal mass ejections (CMEs) suffer from
projection effects, and it is expected that the real velocity
should be larger and the real angular width should be smaller than
the apparent values. Several attempts have been taken to correct
the projection effects, which however led to an inflated average
velocity probably due to the biased choice of CME events. In order
to estimate the overall influence of the projection effects on the
kinematic properties of the CMEs, we perform a forward modeling of real
distributions of CME properties, such as the velocity, the angular
width, and the latitude, by requiring their projected distributions
to best match observations. Such a matching is conducted by Monte
Carlo simulations. According to the derived real distributions, we
found that (1) the average real velocity of all non-full-halo CMEs
is about 514 km s-1, and the average real angular width
is about 33°, in contrast to the corresponding apparent values of
418 km s-1and 42.7° in observations; (2) For the CMEs
with the angular width in the range of 20° - 120°, the average real
velocity is 510 km s-1and the average real angular width
is 43.4°, in contrast to the corresponding apparent values of 392 km
s-1and 52° in observations.
Title: Ultrarelativistic magnetic monopole search with the ANITA-II
balloon-borne radio interferometer
Authors: Detrixhe, M.; Besson, D.; Gorham, P. W.; Allison, P.;
Baughmann, B.; Beatty, J. J.; Belov, K.; Bevan, S.; Binns, W. R.;
Chen, C.; Chen, P.; Clem, J. M.; Connolly, A.; de Marco, D.; Dowkontt,
P. F.; Duvernois, M. A.; Frankenfeld, C.; Grashorn, E. W.; Hogan,
D. P.; Griffith, N.; Hill, B.; Hoover, S.; Israel, M. H.; Javaid,
A.; Liewer, K. M.; Matsuno, S.; Mercurio, B. C.; Miki, C.; Mottram,
M.; Nam, J.; Nichol, R. J.; Palladino, K.; Romero-Wolf, A.; Ruckman,
L.; Saltzberg, D.; Seckel, D.; Varner, G. S.; Vieregg, A. G.; Wang, Y.
Bibcode: 2011PhRvD..83b3513D
Altcode: 2010arXiv1008.1282D
We have conducted a search for extended energy deposition trails left
by ultrarelativistic magnetic monopoles interacting in Antarctic
ice. The nonobservation of any satisfactory candidates in the
31 days of accumulated ANITA-II (Antarctic Impulsive Transient
Antenna) flight data results in an upper limit on the diffuse flux
of relativistic monopoles. We obtain a 90% C.L. limit of order
10-19(cm2ssr)-1 for values of
Lorentz factor, γ, 1010≤γ at the anticipated energy
Etot=1016GeV. This bound is stronger than all
previously published experimental limits for this kinematic range.
Title: "EIT waves" and coronal mass ejections
Authors: Chen, P. F.; Fang, C.
Bibcode: 2011ASInC...2..229C
Altcode: 2011arXiv1108.5274C
Coronal "EIT waves" appear as EUV bright fronts propagating across
a significant part of the solar disk. The intriguing phenomenon
provoked continuing debates on their nature and their relation with
coronal mass ejections (CMEs). In this paper, we first summarize all
the observational features of "EIT waves", which should be accounted
for by any successful model. The theoretical models constructed during
the past 10 years are then reviewed. Finally, the implication of the
"EIT wave" research to the understanding of CMEs is discussed. The
necessity is pointed out to revisit the nature of CME frontal loop.
Title: Thermodynamic Geometry of the Born-Infeld Sitter Black Holes
Authors: Chen, Peng
Bibcode: 2011IJMPA..26.3091C
Altcode: 2011arXiv1104.0546C
Thermodynamic geometry is applied to the Born-Infeld-anti-de Sitter
black hole (BIAdS) in the four dimensions, which is a nonlinear
generalization of the Reissner-Nordström-AdS black hole (RNAdS). We
compute the Weinhold as well as the Ruppeiner scalar curvature and
find that the singular points are not the same with the ones obtained
using the heat capacity. Legendre-invariant metric proposed by Quevedo
and the metric obtained by using the free energy as the thermodynamic
potential are obtained and the corresponding scalar curvatures diverge
at the Davies points.
Title: Testing Strict Hydrostatic Equilibrium in Simulated Clusters
of Galaxies: Implications for A1689
Authors: Molnar, S. M.; Chiu, I. -N.; Umetsu, K.; Chen, P.; Hearn,
N.; Broadhurst, T.; Bryan, G.; Shang, C.
Bibcode: 2010ApJ...724L...1M
Altcode: 2010arXiv1002.4691M
Accurate mass determination of clusters of galaxies is crucial
if they are to be used as cosmological probes. However, there
are some discrepancies between cluster masses determined based
on gravitational lensing and X-ray observations assuming strict
hydrostatic equilibrium (i.e., the equilibrium gas pressure is provided
entirely by thermal pressure). Cosmological simulations suggest that
turbulent gas motions remaining from hierarchical structure formation
may provide a significant contribution to the equilibrium pressure in
clusters. We analyze a sample of massive clusters of galaxies drawn
from high-resolution cosmological simulations and find a significant
contribution (20%-45%) from non-thermal pressure near the center
of relaxed clusters, and, in accord with previous studies, a minimum
contribution at about 0.1 R vir, growing to about 30%-45% at
the virial radius, R vir. Our results strongly suggest that
relaxed clusters should have significant non-thermal support in their
core region. As an example, we test the validity of strict hydrostatic
equilibrium in the well-studied massive galaxy cluster A1689 using the
latest high-resolution gravitational lensing and X-ray observations. We
find a contribution of about 40% from non-thermal pressure within
the core region of A1689, suggesting an alternate explanation for the
mass discrepancy: the strict hydrostatic equilibrium is not valid in
this region.
Title: Erratum: Observational Constraints on the Ultra-high Energy
Cosmic Neutrino Flux from the Second Flight of the ANITA Experiment
Authors: Gorham, P. W.; Allison, P.; Baughman, B. M.; Beatty, J. J.;
Belov, K.; Besson, D. Z.; Bevan, S.; Binns, W. R.; Chen, C.; Chen,
P.; Clem, J. M.; Connolly, A.; Detrixhe, M.; De Marco, D.; Dowkontt,
P. F.; DuVernois, M.; Grashorn, E. W.; Hill, B.; Hoover, S.; Huang,
M.; Israel, M. H.; Javaid, A.; Liewer, K. M.; Matsuno, S.; Mercurio,
B. C.; Miki, C.; Mottram, M.; Nam, J.; Nichol, R. J.; Palladino, K.;
Romero-Wolf, A.; Ruckman, L.; Saltzberg, D.; Seckel, D.; Shang, R. Y.;
Varner, G. S.; Vieregg, A. G.; Wang, Y.
Bibcode: 2010arXiv1011.5004G
Altcode:
This is an erratum to our paper in Physical Review D82:022004,2010,
corresponding to preprint: arXiv:1003.2961 .
Title: Bohai Sea Ice Monitoring By ENVISAT ASAR
Authors: Chen, Peng; Huang, Weigen; Wang, Juan
Bibcode: 2010ESASP.684E..26C
Altcode:
As we all known, the worst sea ice disaster had happened in the
end of 2009. It results in a large damage for fish culture and
transportation. In this paper, we monitored the ice situation using
ENVISAT ASAR SAR data in Dec. 2009 to Jan. 2010. A simple method
was presented and we got the sea ice position and area in the time
sequence. The results show that SAR is a good means for sea ice
monitoring.
Title: Observation of Ultrahigh-Energy Cosmic Rays with the ANITA
Balloon-Borne Radio Interferometer
Authors: Hoover, S.; Nam, J.; Gorham, P. W.; Grashorn, E.; Allison,
P.; Barwick, S. W.; Beatty, J. J.; Belov, K.; Besson, D. Z.; Binns,
W. R.; Chen, C.; Chen, P.; Clem, J. M.; Connolly, A.; Dowkontt, P. F.;
Duvernois, M. A.; Field, R. C.; Goldstein, D.; Vieregg, A. G.; Hast,
C.; Israel, M. H.; Javaid, A.; Kowalski, J.; Learned, J. G.; Liewer,
K. M.; Link, J. T.; Lusczek, E.; Matsuno, S.; Mercurio, B. C.; Miki,
C.; Miočinović, P.; Naudet, C. J.; Ng, J.; Nichol, R. J.; Palladino,
K.; Reil, K.; Romero-Wolf, A.; Rosen, M.; Ruckman, L.; Saltzberg,
D.; Seckel, D.; Varner, G. S.; Walz, D.; Wu, F.
Bibcode: 2010PhRvL.105o1101H
Altcode: 2010arXiv1005.0035H
We report the observation of 16 cosmic ray events with a mean energy of
1.5×1019eV via radio pulses originating from the interaction
of the cosmic ray air shower with the Antarctic geomagnetic field,
a process known as geosynchrotron emission. We present measurements
in the 300-900 MHz range, which are the first self-triggered, first
ultrawide band, first far-field, and the highest energy sample of
cosmic ray events collected with the radio technique. Their properties
are inconsistent with current ground-based geosynchrotron models. The
emission is 100% polarized in the plane perpendicular to the projected
geomagnetic field. Fourteen events are seen to have a phase inversion
due to reflection of the radio beam off the ice surface, and two
additional events are seen directly from above the horizon. Based on
a likelihood analysis, we estimate angular pointing precision of order
2° for the event arrival directions.
Title: The Impact of UV Irradiance on the Composition of Exoplanets
Authors: Line, Michael R.; Chen, P.; Yung, Y. L.
Bibcode: 2010DPS....42.5203L
Altcode: 2010BAAS...42.1070L
A majority of extrasolar giant planets are within a few hundredths of
an AU from their parent star. Their proximity subjects them to high
amounts of UV flux compared to what bodies in our own solar system
receive. Therefore, we expect photochemistry to play a significant role
in the composition of their visible atmospheres. Here we will present
photochemical results that demonstrate the effects of different
UV fields for F, G, K and M stars using HD189733b and GJ436b as
examples. Effects of different eddy mixing strengths and metallicty
will also be investigated as they determine where the boundary between
thermochemistry and transport occurs and thus determine the bulk
composition of the visible atmosphere.
Title: Polarimetric Scattering Characteristics of Ships
Authors: Wang, Juan; Huang, Weigen; Yang, Jingsong; Chen, Peng
Bibcode: 2010ESASP.684E..25W
Altcode:
Polarimetric scattering information is an important electromagnetic
scattering property of synthetic aperture radar (SAR). It has a
potential application for ship classification and identification. This
paper investigates in the polarimetric scattering of several types
of ships by using high-resolution optical images and SAR images. The
research steps are as follows: (1)ships are detected by using a ship
detection method in SAR images, and the profiles of ships are obtained
by using edge detection of SAR images together with mathematical
morphological approach. (2)The type of ships is determined by utilizing
high-resolution optical images. (3)The polarimetric scattering
characteristics of ships are obtained using decomposition methods. It
is shown that different types of ships have different polarimetric
scattering information. This is useful for ship classification and
ship identification.
Title: A New Algorithm For Oil Spill Classification
Authors: Huang, Weigen; Wang, Ligui; Yang, Jinsong; Chen, Peng; Lou,
Xiulin; Wang, Jun; Shi, Aiqin; Xiao, Qingmei
Bibcode: 2010ESASP.684E..28H
Altcode:
This paper presents a new algorithm for oil spill classification. The
algorithm is based on the SAR image characteristics of oil spills and
look-alikes. Oil spill classification capabilities of the SAR image
characteristics including normalized radar cross section (NRCS),
deviation of the NRCS, contrast, correlation and discontinuity have
been investigated. A Fisher discriminate analysis has been adopted to
establish an oil spill classification algorithm. The algorithm has
been performed on European Envisat ASAR images. An accuracy of 90%
correct classification of oil spills has been achieved.
Title: The Dependence of the EIT Wave Velocity on the Magnetic
Field Strength
Authors: Yang, H. Q.; Chen, P. F.
Bibcode: 2010SoPh..266...59Y
Altcode: 2010SoPh..tmp..130Y; 2010SoPh..tmp..118Y; 2010arXiv1002.3955Y
"EIT waves" are a wavelike phenomenon propagating in the corona, which
was initially observed in the extreme ultraviolet (EUV) wavelength
by the EUV Imaging Telescope (EIT). Their nature is still elusive,
with the debate on-going between fast-mode wave model and non-wave
model. In order to distinguish between these models, we investigate the
relation between the EIT wave velocity and the local magnetic field
in the corona. It is found that the two parameters show significant
negative correlation in most of the EIT wave fronts, i.e., the EIT
wave propagates more slowly in the regions of stronger magnetic
field. Such a result poses a big challenge to the fast-mode wave
model, which would predict a strong positive correlation between the
two parameters. However, it is demonstrated that such a result can be
explained by the fieldline stretching model, i.e., that "EIT waves"
are the propagation of apparent brightenings, which are generated by
successive stretching of closed magnetic field lines pushed by the
erupting flux rope during coronal mass ejections (CMEs).
Title: Spectroscopic Analysis of an EIT Wave/dimming Observed by
Hinode/EIS
Authors: Chen, F.; Ding, M. D.; Chen, P. F.
Bibcode: 2010ApJ...720.1254C
Altcode: 2010arXiv1009.3190C
EUV Imaging Telescope (EIT) waves are a wavelike phenomenon propagating
outward from the coronal mass ejection source region, with expanding
dimmings following behind. We present a spectroscopic study of an EIT
wave/dimming event observed by the Hinode/Extreme-ultraviolet Imaging
Spectrometer. Although the identification of the wave front is somewhat
affected by the pre-existing loop structures, the expanding dimming
is well defined. We investigate the line intensity, width, and Doppler
velocity for four EUV lines. In addition to the significant blueshift
implying plasma outflows in the dimming region as revealed in previous
studies, we find that the widths of all four spectral lines increase
at the outer edge of the dimmings. We illustrate that this feature
can be well explained by the field line stretching model, which claims
that EIT waves are apparently moving brightenings that are generated
by the successive stretching of the closed field lines.
Title: Observational constraints on the ultrahigh energy cosmic
neutrino flux from the second flight of the ANITA experiment
Authors: Gorham, P. W.; Allison, P.; Baughman, B. M.; Beatty, J. J.;
Belov, K.; Besson, D. Z.; Bevan, S.; Binns, W. R.; Chen, C.; Chen,
P.; Clem, J. M.; Connolly, A.; Detrixhe, M.; de Marco, D.; Dowkontt,
P. F.; Duvernois, M.; Grashorn, E. W.; Hill, B.; Hoover, S.; Huang,
M.; Israel, M. H.; Javaid, A.; Liewer, K. M.; Matsuno, S.; Mercurio,
B. C.; Miki, C.; Mottram, M.; Nam, J.; Nichol, R. J.; Palladino,
K.; Romero-Wolf, A.; Ruckman, L.; Saltzberg, D.; Seckel, D.; Varner,
G. S.; Vieregg, A. G.; Wang, Y.; ANITA Collaboration
Bibcode: 2010PhRvD..82b2004G
Altcode: 2010arXiv1003.2961T
The Antarctic Impulsive Transient Antenna (ANITA) completed its second
Long Duration Balloon flight in January 2009, with 31 days aloft (28.5
live days) over Antarctica. ANITA searches for impulsive coherent
radio Cherenkov emission from 200 to 1200 MHz, arising from the
Askaryan charge excess in ultrahigh energy neutrino-induced cascades
within Antarctic ice. This flight included significant improvements
over the first flight in payload sensitivity, efficiency, and flight
trajectory. Analysis of in-flight calibration pulses from surface
and subsurface locations verifies the expected sensitivity. In a
blind analysis, we find 2 surviving events on a background, mostly
anthropogenic, of 0.97±0.42 events. We set the strongest limit to
date for 1018-1021eV cosmic neutrinos, excluding
several current cosmogenic neutrino models.
Title: NESSI: the New Mexico Tech Extrasolar Spectroscopic Survey
Instrument
Authors: Jurgenson, C.; Santoro, F.; Creech-Eakman, M.; Houairi, K.;
Bloemhard, H.; Vasisht, G.; Swain, M.; Deroo, P.; Moore, C.; Schmidt,
L.; Boston, P.; Rodeheffer, D.; Chen, P.
Bibcode: 2010SPIE.7735E..19J
Altcode: 2010SPIE.7735E..43J
Less than 20 years after the discovery of the first extrasolar planet,
exoplanetology is rapidly growing with more than one discovery every
week on average since 2007. An important step in exoplanetology is the
chemical characterization of exoplanet atmospheres. It has recently
been shown that molecular signatures of transiting exoplanets can be
studied from the ground. To advance this idea and prepare more ambitious
missions such as THESIS, a dedicated spectrometer named the New Mexico
Tech Extrasolar Spectroscopic Survey Instrument (NESSI) is being
built at New Mexico Tech in collaboration with the NASA Jet Propulsion
Laboratory. NESSI is a purpose-built multi-object spectrograph that
operates in the J, H, and K-bands with a resolution of R = 1000 in each,
as well as a lower resolution of R = 250 across the entire J/H/K region.
Title: Why are halo coronal mass ejections faster?
Authors: Zhang, Qing-Min; Guo, Yang; Chen, Peng-Fei; Ding, Ming-De;
Fang, Cheng
Bibcode: 2010RAA....10..461Z
Altcode: 2010arXiv1002.3953Z
Halo coronal mass ejections (CMEs) have been to be significantly
faster than normal CMEs, which is a long-standing puzzle. In order
to solve the puzzle, we first investigate the observed properties
of 31 limb CMEs that clearly display loop-shaped frontal loops. The
observational results show a strong tendency that slower CMEs are
weaker in white-light intensity. Then, we perform a Monte Carlo
simulation of 20000 artificial limb CMEs that have an average velocity
of ~523 km s-1. The Thomson scattering of these events is
calculated when they are assumed to be observed as limb and halo events,
respectively. It is found that the white-light intensity of many slow
CMEs becomes remarkably reduced when they turn from being viewed as a
limb event to being viewed as a halo event. When the intensity is below
the background solar wind fluctuation, it is assumed that they would
be missed by coronagraphs. The average velocity of “detectable" halo
CMEs is ~922 km s-1 very close to the observed value. This
also indicates that wider events are more likely to be recorded. The
results soundly suggest that the higher average velocity of halo CMEs
is due to that a majority of slow events and some of narrow fast events
carrying less material are so faint that they are blended with the
solar wind fluctuations, and therefore are not observed.
Title: Chinese HJ-1C SAR And Its Wind Mapping Capability
Authors: Huang, Weigen; Chen, Fengfeng; Yang, Jingsong; Fu, Bin;
Chen, Peng; Zhang, Chan
Bibcode: 2010ESASP.679E..21H
Altcode:
Chinese Huan Jing (HJ)-1C synthetic aperture radar (SAR) satellite
has been planed to be launched in 2010. HJ-1C satellite will fly
in a sun-synchronous polar orbit of 500-km altitude. SAR will be
the only sensor on board the satellite. It operates in S band with
VV polarization. Its image mode has the incidence angles 25°and
47°at the near and far sides of the swath respectively. There are
two selectable SAR modes of operation, which are fine resolution
beams and standard beams respectively. The sea surface wind mapping
capability of the SAR has been examined using M4S radar imaging model
developed by Romeiser. The model is based on Bragg scattering theory
in a composite surface model expansion. It accounts for contributions
of the full ocean wave spectrum to the radar backscatter from ocean
surface. The model reproduces absolute normalized radar cross section
(NRCS) values for wide ranges of wind speeds. The model results of HJ-1C
SAR have been compared with the model results of Envisat ASAR. It shows
that HJ-1C SAR is as good as Envisat ASAR at sea surface wind mapping.
Title: Elevation Internal Waves In The South China Sea Observed With
SAR Imagery
Authors: Huang, Weigen; Zhang, Chan; Yang, Jingsong; Fu, Bin;
Chen, Peng
Bibcode: 2010ESASP.679E..12H
Altcode:
ERS-2 and Envisat synthetic aperture radar (SAR) images of oceanic
elevation internal waves in the South China Sea are analyzed. It
is shown that the elevation internal waves appear to be a darker
band leading a brighter band on the SAR images. The characters of
elevation internal waves are derived from SAR images. The spatial
and temporal distributions of the elevation internal waves in the
northern South China Sea are presented. The elevation internal waves
are distributed in an area from 114°W to 116°W longitude and from
20°N to 22°N latitude. They mainly occur in summer when the ocean
vertical stratification is strong. Two case studies are illustrated.
Title: Numerical Simulations of Chromospheric Microflares
Authors: Jiang, R. L.; Fang, C.; Chen, P. F.
Bibcode: 2010ApJ...710.1387J
Altcode: 2010arXiv1012.0661J
With gravity, ionization, and radiation being considered, we perform
2.5 dimensional (2.5D) compressible resistive magnetohydrodynamic (MHD)
simulations of chromospheric magnetic reconnection using the CIP-MOCCT
scheme. The temperature distribution of the quiet-Sun atmospheric
model VALC and the helium abundance (10%) are adopted. Our 2.5D
MHD simulation reproduces qualitatively the temperature enhancement
observed in chromospheric microflares. The temperature enhancement
ΔT is demonstrated to be sensitive to the background magnetic field,
whereas the total evolution time Δt is sensitive to the magnitude
of the anomalous resistivity. Moreover, we found a scaling law,
which is described as ΔT/Δt ~ n H -1.5 B
2.1η0 0.88. Our results also indicate
that the velocity of the upward jet is much greater than that of the
downward jet, and the X-point may move up or down.
Title: New evidence against the fast-mode wave model for EIT waves
Authors: Chen, Peng Fei; Yang, H. Q.
Bibcode: 2010cosp...38.1795C
Altcode: 2010cosp.meet.1795C
"EIT waves" were found to be a coronal phenomenon strongly associated
with coronal mass ejections (CMEs). It was often claimed that they are
the fast-mode waves driven either by solar flares or CMEs. However,
accumulating evidence has shown that many properties of EIT waves
cannot be explained by the fast-mode waves. In this presentation, we
present new evidence to show that the fast-mode wave model would fail
to explain EIT waves. We investigate the relation between the EIT wave
velocity and the local magnetic field in the corona. It is found that
the two parameters show significant negative correlation in most of the
EIT wave fronts, i.e., EIT wave propagates more slowly in the regions
of stronger magnetic field. Such a result poses a big challenge to the
fast-mode wave model, which would predict a strong positive correlation
between the two parameters. However, it is demonstrated that such a
result can be explained by the fieldline stretching model proposed by
Chen et al. (2002, 2005), i.e., "EIT waves" are apparently-propagating
brightenings, which are generated by successive stretching of closed
magnetic field lines pushed by the erupting flux rope during CMEs.
Title: The ANITA experiment: new high-energy neutrino limits and
detection of ultra-high energy cosmic rays
Authors: Binns, Walter; Gorham, P. W.; Allison, P.; Baughmann,
B.; Beatty, J. J.; Belov, K.; Besson, D. Z.; Bevan, S.; Binns,
W. R.; Chen, C.; Chen, P.; Clem, J. M.; Connolly, A.; Detrixhe, M.;
Demarco, D.; Dowkontt, P. F.; Goodhue-Vieregg, A.; Grashorn, E.; Hill,
N. Griffith. B.; Hoover, S.; Israel, M. H.; Javaid, A.; Liewer, K. M.;
Matsuno, S.; Mercurio, B. C.; Miki, C.; Mottram, M.; Nam, J.; Nichol,
R. J.; Palladino, K.; Romero-Wolf, A.; Ruckman, L.; Saltzberg, D.;
Seckel, D.; Varner, G. S.; Wang, Y.
Bibcode: 2010cosp...38.4097B
Altcode: 2010cosp.meet.4097B
The ANITA (ANtarctic Impulsive Transient Antenna) instrument is a
balloon-borne telescope designed to detect coherent radio Cherenkov
emission in the frequency range of 200-1200 MHz from showers produced
in the Antarctic ice by interaction of cosmogenic ultra-high energy
neu-trinos with energy greater than about 3 x 1018 eV. We will discuss
results from the second flight (ANITA-II), which was launched in
December 2008 from Antarctica and included signif-icant improvements
in sensitivity and efficiency for neutrino detection over that of
ANITA-I, which was launched in December 2006. Additionally, the balloon
trajectory of ANITA-II gave substantially more time over deep ice
than that of ANITA-I. We will present upper limits on neutrinos that
constrain models of neutrino origin. In addition, we have 16 events
detected in the ANITA-I flight with strong evidence of their origin
as geosynchrotron radio emission reflecting off of the Antarctic snow
from ultra-high-energy (of order 1019 eV) cosmic-ray air showers. The
increasing aperture of this technique with energy allows us to set
limits on the presence of cosmic rays with energies beyond 1020 eV.
Title: Energetics and magnetic reconnection for solar chromospheric
microflares
Authors: Fang, Cheng; Chen, Peng Fei; Jiang, Rong Lin
Bibcode: 2010cosp...38.2962F
Altcode: 2010cosp.meet.2962F
Solar chromospheric microflares (MFs) are important one of the
small-scale activities in the solar chromosphere. Recent semi-empirical
models indicate that for MFs there is a temperature enhancement of about
2000-2500 K in the chromosphere. The total energy of MFs is about 1027
to 5×1028 ergs. Some evidence implies that magnetic reconnection
in the chromosphere may be responsible for the MFs. Considering
radiative losses and gravity, we have performed 2.5D MHD simulations
in the chromosphere. Our results show that with the combination of
different parameters, including the magnetic field, the height of
reconnection and the anomalous resistivity etc., the semi-empirical
temperature distributions for MFs can be well reproduced. Moveover,
we found a scaling law, which is described as ΔT /Δt ∼ nH -1.5 B
2.3 η0 0.94 . It can be understood by considering the energy balance
during the magnetic reconnection.
Title: Synthetic analysis of a two-ribbon microflare
Authors: Fang, Cheng; Chen, Peng-Fei; Jiang, Rong-Lin; Tang, Yu-Hua
Bibcode: 2010RAA....10...83F
Altcode:
High-resolution Stokes spectral data of Hα, Ca II 8542 Å, and Fe
16302.5 Å lines for a two-ribbon microflare (TRMF) were simultaneously
obtained by the THEMIS telescope on 2002 September 5. We derive the
intensity, velocity, and longitudinal magnetic field maps. The hard
X-ray emission observed by RHESSI provides evidence of nonthermal
particle acceleration in the TRMF. Using Hα and Ca II 8542 Å line
profiles and a non-LTE calculation, we obtain semi-empirical atmospheric
models for the two brightest kernels of the TRMF. Our result indicates
that the temperature enhancement in the chromosphere is more than
2500 K. The kinetic and radiative energies at the kernels are also
estimated, resulting in an estimate of the total energy of the TRMF
of about 2.4 ×1029 erg. Observations indicate that the
TRMF results from the low coronal magnetic reconnection following the
eruption of a small filament. However, the local temperature “bump"
in the chromosphere presents a puzzle for such a standard flare model. A
possible solution to this is discussed.
Title: NESSI: the New Mexico Tech Extrasolar Spectroscopic Survey
Instrument
Authors: Houairi, K.; Jurgenson, C.; Creech-Eakman, M.; Vasisht, G.;
Swain, M.; Santoro, F.; Deroo, P.; Boston, P.; Chen, P.
Bibcode: 2010neme.confP..27H
Altcode:
No abstract at ADS
Title: Magnetic reconnection in the solar lower atmosphere
Authors: Chen, Peng Fei; Fang, Cheng
Bibcode: 2010cosp...38.1943C
Altcode: 2010cosp.meet.1943C
The solar chromosphere and the transition region is a short layer in the
solar lower atmosphere, which, however, is full of dynamic phenomena,
such as Ellerman bombs, blinkers, transion region explosive events,
microflares, and so on. These phenomena are presented at different
wavelengths, and have quite different behaviors. It has been gradually
realized that they may all be related to magnetic reconnection. It
has been shown that, significantly different from the reconnection in
the corona, the magnetic reconnection in the solar lower atmosphere is
strongly affected by the ionization, radiation, abrupt stratification,
and even the p-mode waves. In this paper, we review the observations
and modelings of the subtle effects of these processes on the magnetic
reconnection.
Title: A New View of Coronal Waves from STEREO
Authors: Ma, S.; Wills-Davey, M. J.; Lin, J.; Chen, P. F.; Attrill,
G. D. R.; Chen, H.; Zhao, S.; Li, Q.; Golub, L.
Bibcode: 2009ApJ...707..503M
Altcode:
On 2007 December 7, there was an eruption from AR 10977, which also
hosted a sigmoid. An EUV Imaging Telescope (EIT) wave associated with
this eruption was observed by EUVI on board the Solar Terrestrial
Relations Observatory (STEREO). Using EUVI images in the 171 Å and the
195 Å passbands from both STEREO A and B, we study the morphology and
kinematics of this EIT wave. In the early stages, images of the EIT wave
from the two STEREO spacecrafts differ markedly. We determine that the
EUV fronts observed at the very beginning of the eruption likely include
some intensity contribution from the associated coronal mass ejection
(CME). Additionally, our velocity measurements suggest that the EIT
wave front may propagate at nearly constant velocity. Both results
offer constraints on current models and understanding of EIT waves.
Title: Coronal Mass Ejection Induced Outflows Observed with Hinode/EIS
Authors: Jin, M.; Ding, M. D.; Chen, P. F.; Fang, C.; Imada, S.
Bibcode: 2009ApJ...702...27J
Altcode:
We investigate the outflows associated with two halo coronal mass
ejections (CMEs) that occurred on 2006 December 13 and 14 in NOAA
10930, using the Hinode/EIS observations. Each CME was accompanied by
an EIT wave and coronal dimmings. Dopplergrams in the dimming regions
are obtained from the spectra of seven EIS lines. The results show
that strong outflows are visible in the dimming regions during the
CME eruption at different heights from the lower transition region to
the corona. It is found that the velocity is positively correlated
with the photospheric magnetic field, as well as the magnitude of
the dimming. We estimate the mass loss based on height-dependent EUV
dimmings and find it to be smaller than the CME mass derived from
white-light observations. The mass difference is attributed partly to
the uncertain atmospheric model, and partly to the transition region
outflows, which refill the coronal dimmings.
Title: Automated detection and extraction of coronal dimmings from
SDO/AIA data
Authors: Attrill, Gemma Diana Ruth; Wills-Davey, Meredith J.; Lin,
J.; Chen, P. F.; Chen, H.
Bibcode: 2009shin.confE.100A
Altcode:
The sheer volume of data anticipated from the Solar Dynamics
Observatory/Atmospheric Imaging Assembly (SDO/AIA) highlights the
necessity for the development of automatic detection methods for
various types of solar activity. Initially recognised in the 1970s,
it is now well established that coronal dimmings are closely associated
with coronal mass ejections (CMEs), and are particularly recognised as a
reliable indicator of front-side (halo) CMEs, which can be difficult to
detect in white-light coronagraph data. Existing work demonstrates
that (i) estimates of the dimming volume can be related to the CME mass,
(ii) the spatial extent of coronal dimmings gives information regarding
the angular extent of the associated CME, (iii) measurement of the
magnetic flux in dimming regions can be compared to that contained in
modelled magnetic clouds, (iv) the evolution of coronal dimmings gives
information about the development of the CME post-eruption, and (v)
the distribution of the dimmings and their order of formation can be
used to derive an understanding of the CME's early evolution. An
automated coronal dimming region detection and extraction algorithm
removes visual observer bias from determination of physical quantities
described above. This allows reproducible, quantifiable results to be
mined from very large datasets. The information derived may facilitate
more reliable early space weather detection, as well as offering the
potential for conducting large-sample studies focused on determining
the geoeffectiveness of CMEs, coupled with analysis of their associated
coronal dimmings. We present examples of dimming events extracted
using our algorithm from existing EUV data, demonstrating the potential
for the anticipated application to SDO/AIA data. Metadata returned
by our algorithm include: location, area, volume, mass and dynamics
of coronal dimmings. As well as running on historic datasets, this
algorithm is capable of detecting and extracting coronal dimmings in
near real-time. NASA grants NNX09AB11G and NNH07AB97C supported
this work.
Title: The Antarctic Impulsive Transient Antenna ultra-high energy
neutrino detector: Design, performance, and sensitivity for the
2006-2007 balloon flight
Authors: Anita Collaboration; Gorham, P. W.; Allison, P.; Barwick,
S. W.; Beatty, J. J.; Besson, D. Z.; Binns, W. R.; Chen, C.; Chen, P.;
Clem, J. M.; Connolly, A.; Dowkontt, P. F.; Duvernois, M. A.; Field,
R. C.; Goldstein, D.; Goodhue, A.; Hast, C.; Hebert, C. L.; Hoover,
S.; Israel, M. H.; Kowalski, J.; Learned, J. G.; Liewer, K. M.;
Link, J. T.; Lusczek, E.; Matsuno, S.; Mercurio, B. C.; Miki, C.;
Miočinović, P.; Nam, J.; Naudet, C. J.; Nichol, R. J.; Palladino,
K.; Reil, K.; Romero-Wolf, A.; Rosen, M.; Ruckman, L.; Saltzberg, D.;
Seckel, D.; Varner, G. S.; Walz, D.; Wang, Y.; Williams, C.; Wu, F.;
ANITA Collaboration
Bibcode: 2009APh....32...10A
Altcode: 2010APh....32...10A; 2008arXiv0812.1920A
We present a comprehensive report on the experimental details of the
Antarctic Impulsive Transient Antenna (ANITA) long-duration balloon
payload, including the design philosophy and realization, physics
simulations, performance of the instrument during its first Antarctic
flight completed in January of 2007, and expectations for the limiting
neutrino detection sensitivity.
Title: New Limits on the Ultrahigh Energy Cosmic Neutrino Flux from
the ANITA Experiment
Authors: Gorham, P. W.; Allison, P.; Barwick, S. W.; Beatty, J. J.;
Besson, D. Z.; Binns, W. R.; Chen, C.; Chen, P.; Clem, J. M.; Connolly,
A.; Dowkontt, P. F.; Duvernois, M. A.; Field, R. C.; Goldstein, D.;
Goodhue, A.; Hast, C.; Hebert, C. L.; Hoover, S.; Israel, M. H.;
Kowalski, J.; Learned, J. G.; Liewer, K. M.; Link, J. T.; Lusczek,
E.; Matsuno, S.; Mercurio, B. C.; Miki, C.; Miočinović, P.; Nam,
J.; Naudet, C. J.; Ng, J.; Nichol, R. J.; Palladino, K.; Reil, K.;
Romero-Wolf, A.; Rosen, M.; Ruckman, L.; Saltzberg, D.; Seckel, D.;
Varner, G. S.; Walz, D.; Wang, Y.; Wu, F.
Bibcode: 2009PhRvL.103e1103G
Altcode: 2008arXiv0812.2715A
We report initial results of the first flight of the Antarctic Impulsive
Transient Antenna (ANITA-1) 2006-2007 Long Duration Balloon flight,
which searched for evidence of a diffuse flux of cosmic neutrinos
above energies of Eν≃3×1018eV. ANITA-1 flew
for 35 days looking for radio impulses due to the Askaryan effect
in neutrino-induced electromagnetic showers within the Antarctic ice
sheets. We report here on our initial analysis, which was performed as
a blind search of the data. No neutrino candidates are seen, with no
detected physics background. We set model-independent limits based on
this result. Upper limits derived from our analysis rule out the highest
cosmogenic neutrino models. In a background horizontal-polarization
channel, we also detect six events consistent with radio impulses from
ultrahigh energy extensive air showers.
Title: IceRay: An IceCube-centered radio-Cherenkov GZK neutrino
detector
Authors: Allison, P.; Beatty, J.; Chen, P.; Connolly, A.; Duvernois,
M.; Gorham, P.; Halzen, F.; Hanson, K.; Hoffman, K.; Karle, A.; Kelley,
J.; Landsman, H.; Learned, J.; Miki, C.; Morse, R.; Nichol, R.; Rott,
C.; Ruckman, L.; Seckel, D.; Varner, G.; Williams, D.
Bibcode: 2009NIMPA.604S..64A
Altcode: 2009arXiv0904.1309A
We discuss design considerations and simulation results for IceRay,
a proposed large-scale ultra-high energy (UHE) neutrino detector at
the South Pole. The array is designed to detect the coherent Askaryan
radio emission from UHE neutrino interactions in the ice, with the
goal of detecting the cosmogenic neutrino flux with reasonable event
rates. Operating in coincidence with the IceCube neutrino detector would
allow complete calorimetry of a subset of the events. We also report on
the status of a testbed IceRay station which incorporates both ANITA
and IceCube technology and will provide year-round monitoring of the
radio environment at the South Pole.
Title: The Relation Between EIT Waves and Coronal Mass Ejections
Authors: Chen, P. F.
Bibcode: 2009ApJ...698L.112C
Altcode: 2009arXiv0905.3272C
More and more evidence indicates that "EIT waves" are strongly related
to coronal mass ejections (CMEs). However, it is still not clear how
the two phenomena are related to each other. We investigate a CME event
on 1997 September 9, which was well observed by both the EUV Imaging
Telescope (EIT) and the high-cadence Mark-III K-Coronameter at Mauna
Loa Solar Observatory, and compare the spatial relation between the
"EIT wave" fronts and the CME leading loops. It is found that "EIT wave"
fronts are cospatial with the CME leading loops, and the expanding EUV
dimmings are cospatial with the CME cavity. It is also found that the
CME stopped near the boundary of a coronal hole, a feature common to
observations of "EIT waves." It is suggested that "EIT waves"/dimmings
are the EUV counterparts of the CME leading loop/cavity, based on
which we propose that, as in the case of "EIT waves," CME leading
loops are apparently moving density enhancements that are generated
by successive stretching (or opening-up) of magnetic loops.
Title: Temporal Evolution of Free Magnetic Energy Associated with
Four X-Class Flares
Authors: Jing, Ju; Chen, P. F.; Wiegelmann, Thomas; Xu, Yan; Park,
Sung-Hong; Wang, Haimin
Bibcode: 2009ApJ...696...84J
Altcode:
We study the temporal variation of free magnetic energy
E free around the time of four X-class flares. The
high-cadence photospheric vector magnetograms obtained by the digital
vector magnegograph system at the Big Bear Solar Observatory are
used as the boundary conditions to reconstruct the three-dimensional
nonlinear force-free (NLFF) coronal field. In order to remove the
effect of the net Lorentz force and torque acting in the photosphere,
the vector magnetograms are preprocessed using the method devised by
Wiegelmann et al.. Then a well-tested multigrid-like optimization
code by Wiegelmann is applied to the preprocessed boundary data to
extrapolate the NLFF coronal field with which we are able to estimate
the free energy E free. In all the four events, we find
a significant drop of E free starting ~15 minutes before
the peak time of the associated nonthermal flare emission, although
long-term trend varies from event to event. We discuss the physical
implication of the result, i.e., the magnetic relaxation is already
going on in the corona well before the flare reconnection.
Title: A New View Of Eit Waves And Cmes From Stereo
Authors: Ma, Suli; Wills-Davey, M. J.; Lin, J.; Chen, P. F.; Attrill,
G. D. R.
Bibcode: 2009SPD....40.2107M
Altcode:
Using EUVI and COR images from both STEREO A and B, we study the 3-D
morphology and dynamics of an EIT wave and its associated CME. Our
results imply the following conclusions: first, at the beginning
of the eruption, the EIT wave observations are likely effected
by projection effects due to the CME itself; second, the EIT wave
velocity measurements suggest constant velocity; finally, we find that
weak Earth-directed CMEs may be difficult to observe using existing
instruments. In such cases, EIT waves can be used to predict CMEs.
Title: The Sulfur Cycle on Venus: New Insights from Venus Express
Authors: Yung, Y. L.; Yang, D.; Lee, C.; Liang, M. C.; Chen, P.
Bibcode: 2009LPI....40.2559Y
Altcode:
Sulfur chemistry is critical to the composition of the Venus atmosphere.
Title: New Views of EIT Wave and CME from STEREO
Authors: Ma, S.; Lin, J.; Chen, P.; Chen, H.
Bibcode: 2009arXiv0902.1711M
Altcode:
On 2007 December 7, a small filament located in a small active region
AR 10977 erupted and led to a B1.4 flare. An EIT wave associated
with this eruption was observed both by SOHO/EIT and by EUVI on board
STEREO. According to the observations from SOHO/LASCO and STEREO/COR A,
we found that there was no CME associated with the EIT wave. This seems
to challenge the argument that the cause of EIT waves is CME. However
the data from STEREO/COR B indicated that there was a narrow CME
associated with the EIT wave. This suggests that studying CMEs by
investigating observations made in one direction alone may not be able
to guarantee the reliability of the results.
Title: Energy Spectrum of the Electrons Accelerated by a Reconnection
Electric Field: Exponential or Power Law?
Authors: Liu, W. J.; Chen, P. F.; Ding, M. D.; Fang, C.
Bibcode: 2009ApJ...690.1633L
Altcode: 2008arXiv0809.1212L
The direct current (DC) electric field near the reconnection region
has been proposed as an effective mechanism to accelerate protons and
electrons in solar flares. A power-law energy spectrum was generally
claimed in the simulations of electron acceleration by the reconnection
electric field. However in most of the literature, the electric and
magnetic fields were chosen independently. In this paper, we perform
test-particle simulations of electron acceleration in a reconnecting
magnetic field, where both the electric and magnetic fields are adopted
from numerical simulations of the MHD equations. It is found that the
accelerated electrons present a truncated power-law energy spectrum
with an exponential tail at high energies, which is analogous to the
case of diffusive shock acceleration. The influences of reconnection
parameters on the spectral feature are also investigated, such as the
longitudinal and transverse components of the magnetic field and the
size of the current sheet. It is suggested that the DC electric field
alone might not be able to reproduce the observed single or double
power-law distributions.
Title: BEST - The Balloon-borne Exoplanet Spectroscopy Telescope
Authors: Swain, Mark R.; Chen, P.; Vasisht, G.
Bibcode: 2009AAS...21347520S
Altcode: 2009BAAS...41..439S
A 0.75-m, balloon-borne telescope operating in the stratosphere
offers substantially enhanced detection of molecules in exoplanetary
atmospheres. This is significant because molecules are powerful tracers
of physical and chemical processes in these atmospheres. For instance,
using the Hubble Space Telescope, our team has detected water, methane,
carbon dioxide, and carbon monoxide in the atmosphere of a transiting
hot-Jupiter exoplanet. Furthermore, we demonstrated that spectrally
resolved observations of the primary and secondary eclipse provide
information regarding the chemical compositions of distinct regions
(terminator and dayside) of the atmosphere. Taking advantage of the
stratosphere's drastically improved (compared to ground) seeing and
infrared transparency, a balloon-borne telescope/infrared spectrometer
optimized for instrument stability can substantially enhance wavelength
coverage, spectral resolution, and temporal sampling. Moreover,
it will fill in a critical gap between the spectral coverage of
Spitzer and Hubble telescopes; the mid-infrared spectral regime probes
fundamental vibrational transitions of molecules, and it is uniquely
rich in molecular signatures. We show that such an instrument can be
implemented with existing technology at modest cost to enable exciting
"great observatory" class science.
Title: Evolution of Optical Penumbral and Shear Flows Associated
with the X3.4 Flare of 2006 December 13
Authors: Tan, Changyi; Chen, P. F.; Abramenko, Valentyna; Wang, Haimin
Bibcode: 2009ApJ...690.1820T
Altcode:
The rapid and irreversible decay of penumbrae related to X-class flares
has been found in a number of studies. Since the optical penumbral
flows are closely associated with the morphology of sunspot penumbra,
we use state-of-the-art Hinode data to track penumbral flows in flaring
active regions as well as shear flows close to the flaring neutral
line. This paper concentrates on AR 10930 around the time of an X3.4
flare on 2006 December 13. We utilize the seeing-free solar optical
telescope G-band data as a tracer to obtain the horizontal component
of the penumbral and shear flows by local correlation tracking, and
Stokes-V data to register positive and negative magnetic elements along
the magnetic neutral line. We find that: (1) an obvious penumbral decay
appears in this active region intimately associated with the X3.4 flare;
(2) the mean magnitude of the horizontal speeds of the penumbral flows
within the penumbral decay areas temporally and spatially varies from
0.6 to 1.1 km s-1 (3) the penumbral flow decreases before
the flare eruption in two of the four penumbral decay areas; (4) the
mean shear flows along the magnetic neutral line of this δ-sunspot
started to decrease before the flare and continue to decrease for
another hour after the flare. The magnitude of this flow apparently
dropped from 0.6 to 0.3 km s-1. We propose that the decays
of the penumbra and the penumbral flow are related to the magnetic
rearrangement involved in the coronal mass ejection/flare events.
Title: Exoplanet Characterization and the Search for Life
Authors: Kasting, James; Traub, W.; Roberge, A.; Leger, A.; Schwartz,
A.; Wootten, A.; Vosteen, A.; Lo, A.; Brack, A.; Tanner, A.; Coustenis,
A.; Lane, B.; Oppenheimer, B.; Mennesson, B.; Lopez, B.; Grillmair, C.;
Beichman, C.; Cockell, C.; Hanot, C.; McCarthy, C.; Stark, C.; Marois,
C.; Aime, C.; Angerhausen, D.; Montes, D.; Wilner, D.; Defrere, D.;
Mourard, D.; Lin, D.; Kite, E.; Chassefiere, E.; Malbet, F.; Tian,
F.; Westall, F.; Illingworth, G.; Vasisht, G.; Serabyn, G.; Marcy, G.;
Bryden, G.; White, G.; Laughlin, G.; Torres, G.; Hammel, H.; Ferguson,
H.; Shibai, H.; Rottgering, H.; Surdej, J.; Wiseman, J.; Ge, J.; Bally,
J.; Krist, J.; Monnier, J.; Trauger, J.; Horner, J.; Catanzarite, J.;
Harrington, J.; Nishikawa, J.; Stapelfeldt, K.; von Braun, K.; Biazzo,
K.; Carpenter, K.; Balasubramanian, K.; Kaltenegger, L.; Postman, M.;
Spaans, M.; Turnbull, M.; Levine, M.; Burchell, M.; Ealey, M.; Kuchner,
M.; Marley, M.; Dominik, M.; Mountain, M.; Kenworthy, M.; Muterspaugh,
M.; Shao, M.; Zhao, M.; Tamura, M.; Kasdin, N.; Haghighipour, N.;
Kiang, N.; Elias, N.; Woolf, N.; Mason, N.; Absil, O.; Guyon, O.;
Lay, O.; Borde, P.; Fouque, P.; Kalas, P.; Lowrance, P.; Plavchan,
P.; Hinz, P.; Kervella, P.; Chen, P.; Akeson, R.; Soummer, R.; Waters,
R.; Barry, R.; Kendrick, R.; Brown, R.; Vanderbei, R.; Woodruff, R.;
Danner, R.; Allen, R.; Polidan, R.; Seager, S.; MacPhee, S.; Hosseini,
S.; Metchev, S.; Kafka, S.; Ridgway, S.; Rinehart, S.; Unwin, S.;
Shaklan, S.; ten Brummelaar, T.; Mazeh, T.; Meadows, V.; Weiss, W.;
Danchi, W.; Ip, W.; Rabbia, Y.
Bibcode: 2009astro2010S.151K
Altcode: 2009arXiv0911.2936K
Over 300 extrasolar planets (exoplanets) have been detected orbiting
nearby stars. We now hope to conduct a census of all planets around
nearby stars and to characterize their atmospheres and surfaces with
spectroscopy. Rocky planets within their star's habitable zones have
the highest priority, as these have the potential to harbor life. Our
science goal is to find and characterize all nearby exoplanets; this
requires that we measure the mass, orbit, and spectroscopic signature of
each one at visible and infrared wavelengths. The techniques for doing
this are at hand today. Within the decade we could answer long-standing
questions about the evolution and nature of other planetary systems,
and we could search for clues as to whether life exists elsewhere in
our galactic neighborhood.
Title: Aquarius - A Compact and Lightweight Ice and Liquid Water
Isotope Analyzer
Authors: Christensen, L. E.; Smith, M.; Chen, P.
Bibcode: 2008AGUFM.H51C0825C
Altcode:
We are developing Aquarius, a multipurpose ice and liquid water
isotope analyzer. Aquarius combines a liquid-to-gas converter with
a laser spectrometer to measure water isotopologue abundances with
per mil accuracy. Its compact size will be ideal for field hydrology,
while an optional interface with a thermal ice drill will enable in
situ measurement of polar climate records. Upon completion, Aquarius
will be used for extraterrestrial studies including identifying Mars"
past climate cycles, tracing Martian water history, and measuring
deuterium abundance in the primordial solar system as recorded in comet
ice. Anticipated terrestrial applications include sampling aquifers
to assess drinking water quality in developing countries.
Title: Results from the ANITA experiment (Analysis A)
Authors: Nam, Jiwoo; ANITA Collaboration; Gorham, P. W.; Barwick,
S. W.; Beatty, J. J.; Besson, D. Z.; Binns, W. R.; Chen, C.; Chen, P.;
Clem, J. M.; Connolly, A.; Dowkontt, P. F.; Du Vernois, M. A.; Field,
R. C.; Goldstein, D. J.; Goodhue, A.; Hast, C.; Hebert, C. L.; Hoover,
S.; Israel, M. H.; Javaid, A.; Kowalski, J.; Learned, J. G.; Liewer,
K. M.; Link, J. T.; Lusczek, E.; Matsuno, S.; Mercurio, B. C.; Miki,
C.; Miocinovic, P.; Nam, J.; Naudet, C. J.; Ng, J.; Nichol, R. J.;
Palladino, K. J.; Reil, K.; Romero-Wolf, A.; Rosen, M.; Saltzberg,
D.; Seckel, D.; Varner, G. S.; Walz, D.; Wu, F.
Bibcode: 2008JPhCS.136d2062N
Altcode:
The ANITA (ANtarctic Impulsive Transient Antenna) is a balloon-borne
neutrino telescope which consists of an array of 32 broadband horn
antennas. It successfully completed a 35 day flight over Antarctica
during the 2006-2007 austral summer. The primary goal of ANITA is to
search for astrophysical neutrinos with energies E > 1019
eV by detecting radio Cherenkov signals from neutrino-induced showers in
the Antarctic ice. There are two independent data analysis groups in the
ANITA experiment based on data blinding and analysis methods. We present
results from one of the analysis groups with an event blinding approach.
Title: A Magnetic Flux Tube Oscillation Model for QPOs in SGR
Giant Flares
Authors: Ma, Bo; Li, Xiang-Dong; Chen, P. F.
Bibcode: 2008ApJ...686..492M
Altcode: 2008arXiv0807.0683M
Giant flares from soft gamma-ray repeaters (SGRs) are one of the most
violent phenomena in neutron stars. Quasi-periodic oscillations (QPOs)
with frequencies ranging from 18 to 1840 Hz have been discovered in
the tails of giant flares from two SGRs and were ascribed to seismic
vibrations or torsional oscillations of magnetars. Here we propose an
alternative explanation for the QPOs in terms of standing sausage mode
oscillations of flux tubes in the magnetar coronae. We show that most
of the QPOs observed in SGR giant flares could be well accounted for
except for those with very high frequencies (625 and 1840 Hz).
Title: Observations of microwave continuum emission from air shower
plasmas
Authors: Gorham, P. W.; Lehtinen, N. G.; Varner, G. S.; Beatty,
J. J.; Connolly, A.; Chen, P.; Conde, M. E.; Gai, W.; Hast, C.;
Hebert, C. L.; Miki, C.; Konecny, R.; Kowalski, J.; Ng, J.; Power,
J. G.; Reil, K.; Ruckman, L.; Saltzberg, D.; Stokes, B. T.; Walz, D.
Bibcode: 2008PhRvD..78c2007G
Altcode: 2007arXiv0705.2589G
We investigate a possible new technique for microwave detection of
cosmic-ray extensive air showers which relies on detection of expected
continuum radiation in the microwave range, caused by free-electron
collisions with neutrals in the tenuous plasma left after the passage
of the shower. We performed an initial experiment at the Argonne
Wakefield Accelerator laboratory in 2003 and measured broadband
microwave emission from air ionized via high-energy electrons and
photons. A follow-up experiment at the Stanford Linear Accelerator
Center in the summer of 2004 confirmed the major features of the
previous Argonne Wakefield Accelerator observations with better
precision. Prompted by these results we built a prototype detector using
satellite television technology and have made measurements suggestive
of the detection of cosmic-ray extensive air showers. The method, if
confirmed by experiments now in progress, could provide a high-duty
cycle complement to current nitrogen fluorescence observations.
Title: Exploring Alien Solar Systems from the Moon
Authors: Schultz, A. B.; Lyon, R.; Jordan, I.; Bruhweiler, F.; Kochte,
M.; Rodrigue, M.; Bennum, D.; Chen, P.; Cheng, K. -P.
Bibcode: 2008LPICo1415.2047S
Altcode:
We propose a unique coronagraphic approach to image exoplanets;
an external occulter plus a hybrid telescope operating on the moon,
a heliostat-like telescope design with an external occulter.
Title: SOHO/SUMER observations of prominence oscillation before
eruption
Authors: Chen, P. F.; Innes, D. E.; Solanki, S. K.
Bibcode: 2008A&A...484..487C
Altcode: 2008arXiv0802.1961C
Context: Coronal mass ejections (CMEs), as a large-scale eruptive
phenomenon, often reveal some precursors in the initiation phase, e.g.,
X-ray brightening, filament darkening, etc., which are useful for CME
modelling and space weather forecasting.
Aims: With the Solar
Ultraviolet Measurements of Emitted Radiation (SUMER) spectroscopic
observations of the 2000 September 26 CME, we propose another
precursor for CMEs, namely, long-time prominence oscillations.
Methods: We observed the prominence oscillation-and-eruption event by
ground-based Hα telescopes and space-borne white-light, EUV imaging,
and spectroscopic instruments. In particular, the SUMER slit was
observing the prominence in a sit-and-stare mode.
Results:
The observations indicate that a siphon flow was moving from the
proximity of the prominence to a site at a projected distance of 270'',
which was followed by repetitive Hα surges and continual prominence
oscillations. The oscillation lasted 4 hours before the prominence
erupted as a blob-like CME. The analysis of the multiwavelength
data indicates that the whole series of processes fits well into the
emerging flux trigger mechanism for CMEs. In this mechanism, emerging
magnetic flux drives a siphon flow due to increased gas pressure
where the background polarity emerges. It also drives Hα surges
through magnetic reconnection where the opposite polarity emerges. The
magnetic reconnection triggers the prominence oscillations, as well
as its loss of equilibrium, which finally leads to the eruption of the
prominence. It is also found that the reconnection between the emerging
flux and the pre-existing magnetic loop proceeds in an intermittent,
probably quasi-periodic, way.
Title: Initiation and propagation of coronal mass ejections
Authors: Chen, P. F.
Bibcode: 2008JApA...29..179C
Altcode: 2007arXiv0712.3632C
This paper reviews recent progress in the research on the initiation and
propagation of CMEs. In the initiation part, several trigger mechanisms
are discussed; In the propagation part, the observations and modelings
of EIT waves/dimmings, as the EUV counterparts of CMEs, are described.
Title: In situ radioglaciological measurements near Taylor Dome,
Antarctica and implications for ultra-high energy (UHE) neutrino
astronomy
Authors: Besson, D. Z.; Jenkins, J.; Matsuno, S.; Nam, J.; Smith,
M.; Barwick, S. W.; Beatty, J. J.; Binns, W. R.; Chen, C.; Chen,
P.; Clem, J. M.; Connolly, A.; Dowkontt, P. F.; DuVernois, M. A.;
Field, R. C.; Goldstein, D.; Gorham, P. W.; Goodhue, A.; Hast, C.;
Hebert, C. L.; Hoover, S.; Israel, M. H.; Kowalski, J.; Learned,
J. G.; Liewer, K. M.; Link, J. T.; Lusczek, E.; Mercurio, B.; Miki,
C.; Miočinović, P.; Naudet, C. J.; Ng, J.; Nichol, R.; Palladino,
K.; Reil, K.; Romero-Wolf, A.; Rosen, M.; Ruckman, L.; Saltzberg,
D.; Seckel, D.; Varner, G. S.; Walz, D.; Wu, F.
Bibcode: 2008APh....29..130B
Altcode: 2007astro.ph..3413B
Radiowave detection of the Cherenkov radiation produced by neutrino-ice
collisions requires an understanding of the radiofrequency (RF) response
of cold polar ice. We herein report on a series of radioglaciological
measurements performed approximately 10 km north of Taylor Dome
Station, Antarctica from December 6, 2006-December 16, 2006. Using
RF signals broadcast from: (a) an englacial discone, submerged to a
depth of 100 m and broadcasting to a surface dual-polarization horn
receiver, and (b) a dual-polarization horn antenna on the surface
transmitting signals which reflect off the underlying bed and back
up to the surface receiver, we have made time-domain estimates of
both the real (index-of-refraction "n") and imaginary (attenuation
length "Latten") components of the complex ice dielectric
constant. We have also measured the uniformity of ice response along
two orthogonal axes in the horizontal plane. We observe an apparent
wavespeed asymmetry of order 0.1% between two orthogonal linear
polarizations projected into the horizontal plane, consistent with
some previous measurements, but somewhat lower than others.
Title: Simulations of the periodic flaring rate on YY Gem
Authors: Gao, D. H.; Chen, P. F.; Ding, M. D.; Li, X. D.
Bibcode: 2008MNRAS.384.1355G
Altcode: 2008MNRAS.tmp..126G; 2007arXiv0712.2300G
The binary YY Gem shows many interesting properties, one of which
is the periodicity in its flaring rate. The period, which is about
48 +/- 3 min, was ever interpreted in terms of the oscillation of
a filament. In this paper, we propose a new model to explain this
phenomenon by means of 2.5D magnetohydrodynamic (MHD) numerical
simulations. It is found that magnetic reconnection is induced as the
coronal loops rooted on both stars inflate and approach each other,
which is driven by the differential stellar rotation. The magnetic
reconnection is modulated by fast-mode magnetoacoustic waves which are
trapped between the surfaces of the two stars, so that the reconnection
rate presents a periodic behaviour. With the typical parameters for the
binary system, the observed period can be reproduced. We also derive
an empirical formula to relate the period of the flaring rate to the
coronal temperature and density, as well as the magnetic field.
Title: Air fluorescence measurements in the spectral range 300 420
nm using a 28.5 GeV electron beam
Authors: Abbasi, R.; Abu-Zayyad, T.; Belov, K.; Belz, J.; Cao, Z.;
Dalton, M.; Fedorova, Y.; Hüntemeyer, P.; Jones, B. F.; Jui, C. C. H.;
Loh, E. C.; Manago, N.; Martens, K.; Matthews, J. N.; Maestas, M.;
Rodriguez, D.; Smith, J.; Sokolsky, P.; Springer, R. W.; Thomas, J.;
Thomas, S.; Chen, P.; Field, C.; Hast, C.; Iverson, R.; Ng, J. S. T.;
Odian, A.; Reil, K.; Walz, D.; Bergman, D. R.; Thomson, G.; Zech,
A.; Chang, F. -Y.; Chen, C. -C.; Chen, C. -W.; Huang, M. A.; Hwang,
W. -Y. P.; Lin, G. -L.
Bibcode: 2008APh....29...77A
Altcode: 2007arXiv0708.3116A
Measurements are reported of the yield and spectrum of fluorescence,
excited by a 28.5 GeV electron beam, in air at a range of pressures
of interest to ultra-high energy cosmic ray detectors. The wavelength
range was 300 420 nm. System calibration has been performed using
Rayleigh scattering of a nitrogen laser beam. In atmospheric pressure
dry air at 304 K the total yield is 20.8 ± 1.6 photons per MeV.
Title: SOHO/SUMER observations of prominence oscillation before
eruption
Authors: Chen, P. F.; Innes, D. E.; Solanki, Sami
Bibcode: 2008cosp...37..502C
Altcode: 2008cosp.meet..502C
Coronal mass ejections (CMEs) often reveal some precursors in the
initiation phase, such as X- ray brightening and filament darkening,
which are useful for CME modeling and space weather forecast. With the
SOHO/SUMER spectroscopic observations of the 2000 September 26 event,
we propose another precursor for CME eruptions, namely, long-time
prominence oscillations. The observations indicate that a siphon
flow was moving from the proximity of the prominence to a far site,
which was followed by repetitive Hα surges and continual prominence
oscillations. The oscillation lasted 4 hours before the prominence
erupted as a blob-like CME. The analysis of the multiwavelength
data indicates that the whole series of processes fits well into the
emerging flux trigger mechanism for CMEs. In this mechanism, emerging
magnetic flux drives a siphon flow due to increased gas pressure
where the background polarity emerges. It also drives Hα surges
through magnetic reconnection where the opposite polarity emerges. The
magnetic reconnection triggers the prominence oscillations, as well
as its loss of equilibrium, which finally leads to the eruption of the
prominence. It is also found that the reconnection between the emerging
flux and the pre-existing magnetic loop proceeds in an intermittent,
probably quasiperiodic, way.
Title: The nature and origin of coronal waves
Authors: Chen, P. F.
Bibcode: 2008cosp...37..501C
Altcode: 2008cosp.meet..501C
Coronal waves, often referred as "EIT waves", attracted wide interest
due to their intriguing properties and their significance in space
weather forecast. Several models have been proposed on their nature and
origin, which are still being hotly debated. In this talk, we present
a review on the development of these models, with the emphasis on our
model where coronal waves are interpreted to be generated by successive
opening of closed magnetic field lines during coronal mass ejections.
Title: Numerical simulation of magnetic reconnection in the solar
lower atmosphere
Authors: Fang, Cheng; Xu, Xiao Yan; Chen, P. F.
Bibcode: 2008cosp...37..853F
Altcode: 2008cosp.meet..853F
In the solar lower atmosphere there are many small-scale activities,
such as Ellerman bombs (EBs) and microflares (MFs). Recent
semi-empirical models indicate that for both EBs and MFs there is a
temperature enhancement in the upper photosphere and chromosphere,
where the temperature bump is located deeper for EBs than for
MFs. Some evidence implies that magnetic reconnection in the solar
lower atmosphere may be responsible for the formation of EBs and
MFs. Considering radiative losses and gravity, we have performed
numerical simulations in the solar lower atmosphere. Our results
show that with the combination of different parameters, including
the magnetic field, the height of reconnection and the anomalous
resistivity etc., the semi-empirical temperature distributions for
EBs and MFs can be well reproduced. Particle acceleration during
the magnetic reconnection and its role on the heating of the lower
atmosphere are also discussed.
Title: Preliminary Result from Anita Experiment
Authors: Nam, Jiwoo; Gorham, P. W.; Barwick, S. W.; Beatty, J. J.;
Besson, D. Z.; Binns, W. R.; Chen, C.; Chen, P.; Clem, J. M.; Connolly,
A.; Dowkontt, P. F.; Duvernois, M. A.; Field, R. C.; Goldstein,
D. J.; Goodhue, A.; Hast, C.; Hebert, C. L.; Hoover, S.; Israel,
M. H.; Javaid, A.; Kowalski, J.; Learned, J. G.; Liewer, K. M.;
Link, J. T.; Lusczek, E.; Matsuno, S.; Mercurio, B. C.; Miki, C.;
Miočinović, P.; Naudet, C. J.; Ng, J.; Nichol, R. J.; Palladino,
K. J.; Reil, K.; Romero-Wolf, A.; Rosen, M.; Saltzberg, D.; Seckel,
D.; Varner, G. S.; Walz, D.; Wu, F.
Bibcode: 2008MPLA...23.1419N
Altcode:
The ANITA (ANtarctic Impulsive Transient Antenna) experiment is a
balloon-borne neutrino telescope which consists of an array of 32
broad-band horn antennas. It successfully completed a 35 day flight
over Antarctica during the 2006-2007 austral summer. The primary goal
of ANITA is to search for astrophysical neutrinos with energies E >
1019eV by detecting radio Cherenkov signals from neutrino
induced showers in the Antarctic ice. We present preliminary results
from ongoing analyses of ANITA data.
Title: Radiofrequency Ice Properties Measurements at Taylor Dome,
Antarctica, in support of the ANITA experiment
Authors: Besson, D. Z.; Nam, J.; Matsuno, S.; Barwick, S. W.; Beatty,
J. J.; Binns, W. R.; Chen, C.; Chen, P.; Clem, J. M.; Connolly, A.;
Dowkontt, P. F.; DuVernois, M. A.; Field, R. C.; Goldstein, D.;
Goodhue, A.; Gorham, P. W.; Hast, C.; Hebert, C. L.; Hoover, S.;
Israel, M. H.; Kowalski, J.; Learned, J. G.; Liewer, K. M.; Link,
J. T.; Lusczek, E.; Mercurio, B.; Miki, C.; Miočinović, P.; Naudet,
C. J.; Ng, J.; Nichol, R.; Palladino, K.; Reil, K.; Romero-Wolf, A.;
Rosen, M.; Ruckman, L.; Saltzberg, D.; Seckel, D.; Varner, G. S.;
Walz, D.; Wu, F.
Bibcode: 2008ICRC....3.1241B
Altcode: 2008ICRC...30c1241B
A series of ice properties' measurements were made in December, 2006
in support of the balloon-borne ANITA neutrino detection effort. Of
particular importance is the electric field attenuation length in the
range 200-1000 MHz as well as signal transmission across the air-ice
boundary. We present measurements of the temperature profile over
the upper 100 meters of ice, radiofrequency attenuation lengths,
and surface roughness effects on signal propagation.
Title: A Statistical Study on the Filament Eruption Caused by New
Emerging Flux
Authors: Xu, Xiao-yan; Fang, Cheng; Chen, Peng-fei
Bibcode: 2008ChA&A..32...56X
Altcode:
Observations indicated that solar coronal mass ejections (CMEs) are
closely asociated with reconnection-favored new flux emergence. By
means of numerial simulations, a physical model of the emerging
flux trigger mechanism for CMEs is proposed and explained well the
observational results. Based upon this model, leaving the gravity and
heat conduction out of consideration, the theoretical results of 2.5
dimensional numerical simulations indicate that whether a CME can be
triggered depends on both the amount and the location of an emerging
flux, besides its polarity orientation. Furthermore, the eruption and
non-eruption regimes are presented in parameter space. By use of 15
filament eruption events in 2002 and 2003 and 44 non-eruption events in
2002, the results of a statistical study on the properties of emerging
flux including its polarity orientation, its location and the amount
of flux show that not all the emerging flux can make a filament to
lose equilibrium and trigger the onset of a CME, The statistic results
basically support the theoretical results of numerical simulations. This
research provides useful information for the space weather forecast.
Title: Performance assessment study of the balloon-borne astronomical
soft gamma-ray polarimeter PoGOLite
Authors: Arimoto, M.; Kanai, Y.; Ueno, M.; Kataoka, J.; Kawai, N.;
Tanaka, T.; Yamamoto, K.; Takahashi, H.; Mizuno, T.; Fukazawa, Y.;
Axelsson, M.; Kiss, M.; Marini Bettolo, C.; Carlson, P.; Klamra, W.;
Pearce, M.; Chen, P.; Craig, B.; Kamae, T.; Madejski, G.; Ng, J. S. T.;
Rogers, R.; Tajima, H.; Thurston, T. S.; Saito, Y.; Takahashi, T.;
Gunji, S.; Bjornsson, C. -I.; Larsson, S.; Ryde, F.; Bogaert, G.;
Varner, G.
Bibcode: 2007PhyE...40..438A
Altcode:
Measurements of polarization play a crucial role in the understanding
of the dominant emission mechanism of astronomical sources. Polarized
Gamma-ray Observer-Light version (PoGOLite) is a balloon-borne
astronomical soft gamma-ray polarimeter at the 25 80 keV band. The
PoGOLite detector consists of a hexagonal close-packed array of 217
Phoswich detector cells (PDCs) and side anti-coincidence shields
(SASs) made of BGO crystals surrounding PDCs. Each PDC consists of a
slow hollow scintillator, a fast scintillator and a BGO crystal that
connects to a photomultiplier tube at the end. To examine the PoGOLite's
capability and estimate the performance, we conducted experiments with
the PDC using radioisotope 241Am. In addition, we compared
this result with performance expected by Monte Carlo simulation with
Geant4. As a result, we found that the actual PDC has the capability
to detect a 100 m Crab source until 80 keV.
Title: Planetscope Precursor Experiment
Authors: Traub, Wesley A.; Chen, P.
Bibcode: 2007AAS...211.3006T
Altcode: 2007BAAS...39..782T
We present calculations and data on astronomical seeing from a balloon
platform in the stratosphere. This work is in preparation for observing
exoplanets with the Planetscope instrument, a proposed balloon-borne
telescope and coronagraph. We use published satellite measurements of
optical inhomogeneites in the stratosphere. We calculate that the free
atmosphere above balloon altitudes will perturb a stellar wavefront
by a comfortably small amount. We predict that speckles in the focal
plane of an optical telescope will be faint, so that a number of
known radial-velocity planets should be observable with a telescope
and coronagraph. We also investigate the possible contribution of
the stratospheric equivalent of a ground-based telescope's "dome
seeing". This could arise from air density fluctuations caused by
temperature differences between the ambient air and the telescope,
gondola, or balloon. We flew a simple experiment in September 2007 to
measure this effect. Data from this experiment will be reported.
Title: XRT and EIS Observations of Reconnection Associated Phenomena
Authors: Shiota, D.; Isobe, H.; Brooks, D. H.; Chen, P. -F.;
Shibata, K.
Bibcode: 2007ASPC..369..439S
Altcode:
Based on the results of numerical simulations, we sythesized EIS and
XRT images of reconnection flows associated with an eruptive flare. The
results suggest that reconnection inflows can be observed as pairs of
blue- and red-shifted components just above the X-ray arcade in the
low temperature lines. It is found that the Doppler velocities are
larger in the lower temperature line spectra. Reconnection outflows
can also be observed as pairs of blue- and red-shifted components with
an asymmetry in the high temperature line spectra.
Title: Near-Infrared Spectra of Jupiter's North Temperate Belt
Disturbance (NTBs) of 2007
Authors: Yanamandra-Fisher, Padma A.; Orton, G. S.; Jezweski, S.;
Sitko, M.; Lynch, D. K.; Rudy, R.; Baines, K. H.; Momary, T. W.;
Chen, P.
Bibcode: 2007DPS....39.1911Y
Altcode: 2007BAAS...39..446Y
Starting in late 2005, Jupiter has been experiencing an era of
atmospheric global upheaval, with various localized and axisymmetric
changes occurring all over the planet. We focus on the near-infrared
spectra of the North Temperate Belt disturbance (NTBs), at latitude
of 24 degrees north. The outbreak was identified late March 2007 as
a bright feature high in the atmosphere, which quickly encircled the
planet in about two months. Although visible, near- and mid-infrared
imaging data was acquired, near-infrared spectra of the feature
were acquired with a medium-resolution near-infrared spectrometer,
SpeX, at the NASA/Infra Red Telescope Facility (IRTF) on May 1-2,
2007. The feature dissipated within days thereafter. The 15 x 0.8 arc
sec slit spectra were spatially resolved into sub apertures along the
spectral slit (1.0 x 0.8 arc sec). This allowed us to geometrically
register the spectral data for the discrete feature, without losing
data integrity. Our first results indicate the presence of ammonia ice,
similar to the spectrum of ammonia clouds identified in Galileo/Jupiter
data (Baines et al. 2002, Icarus, 159). The strength of the ammonia ice
features varies from the localized "head” of the feature along the
length of the slit (i.e., longitude). We shall compare these results
with (1) spectral analysis of other regions of Jupiter that have not
undergone such dramatic changes to determine the differences between
them and (2) other spectra obtained from NASA/IRTF and Lick Observatory
with The Aerospace Corporation's visible/near-infrared spectrometer
VNIRIS to determine the temporal evolution of NTBs disturbance and
(3) compare with spectra of other disturbances such as those currently
occurring in the South Equatorial Belt (SEB).
Title: Observations of the Askaryan Effect in Ice
Authors: Gorham, P. W.; Barwick, S. W.; Beatty, J. J.; Besson, D. Z.;
Binns, W. R.; Chen, C.; Chen, P.; Clem, J. M.; Connolly, A.; Dowkontt,
P. F.; Duvernois, M. A.; Field, R. C.; Goldstein, D.; Goodhue, A.;
Hast, C.; Hebert, C. L.; Hoover, S.; Israel, M. H.; Kowalski, J.;
Learned, J. G.; Liewer, K. M.; Link, J. T.; Lusczek, E.; Matsuno, S.;
Mercurio, B.; Miki, C.; Miočinović, P.; Nam, J.; Naudet, C. J.; Ng,
J.; Nichol, R.; Palladino, K.; Reil, K.; Romero-Wolf, A.; Rosen, M.;
Ruckman, L.; Saltzberg, D.; Seckel, D.; Varner, G. S.; Walz, D.; Wu, F.
Bibcode: 2007PhRvL..99q1101G
Altcode: 2006hep.ex...11008A; 2006hep.ex...11008T
We report on observations of coherent, impulsive radio Cherenkov
radiation from electromagnetic showers in solid ice. This is the
first observation of the Askaryan effect in ice. As part of the
complete validation process for the ANITA experiment, we performed
an experiment at the Stanford Linear Accelerator Center in June 2006
using a 7.5 metric ton ice target. We measure for the first time
the large-scale angular dependence of the radiation pattern, a major
factor in determining the solid-angle acceptance of ultrahigh-energy
neutrino detectors.
Title: Statistical study on filament eruption caused by emerging flux
Authors: Xu, X. Y.; Fang, C.; Chen, P. F.
Bibcode: 2007AcASn..48..181X
Altcode:
Observations indicated that solar coronal mass ejections
(CMEs) are strongly associated with reconnection-favored flux
emergence. As suggested by observations, two types of emerging flux
with reconnection-favored direction can trigger filament eruptions
(and then CMEs): one is within the filament channel, and the other
is on the outer edge of the channel. Based on numerical simulations,
a physical model of the emerging flux trigger mechanism for CMEs is
proposed, which explained well the observational phenomena. Using
2.5 dimensional numerical simulations with the gravity and heat
conduction being omitted, the eruption and non-eruption regimes are
presented in parameter space, which indicate that whether a CME can be
triggered depends on both the amount and the location of an emerging
flux, besides its polarity orientation. Furthermore, by analyzing15
eruption events in 2002 and 2003 and 44 non-eruption events in 2002,
the relation between filament eruptions (and CMEs) and the properties
of emerging flux including its polarity orientation, its location,
and the amount of the unsigned flux is studied statistically. The
results show that not all the emerging flux can make a filament lose
equilibrium and then trigger the onset of a CME. The statistic results
basically support the theoretical numerical simulations, in which the
2.5 dimensional time dependent compressible resistive MHD equations
are numerically solved with a multi-step implicit scheme. This research
provides useful information for the space weather forecast.
Title: Analysis of ISO SWS01 spectra of S stars
Authors: Yang, X. H.; Chen, P.; Wang, J.; He, J.
Bibcode: 2007A&A...463..663Y
Altcode:
The Infrared Space Observatory (ISO) Short-Wavelength Spectrometer
(SWS01) plays an important role in studying properties of S stars. We
reduce and analyze the SWS01 spectra of 17 S stars, and identify the
candidate carriers of molecular absorption features. The ISO Spectral
Analysis Package (ISAP) developed by the LWS and SWS Instrument Teams
and Data Centers is used to process and analyze the SWS01 spectra of
17 S stars. The ISO archives of 17 S stars are obtained from the ISO
database. Of 17 S stars, two stars are extrinsic S stars, the others are
intrinsic S stars. The 15 intrinsic S stars can be divided into three
groups (6 stars for Group I, 7 stars for Group II, and 2 stars for
Group III) according to their Infrared Astronomical Satellite (IRAS)
low-resolution spectra (LRS) and dust mass-loss rate dot{M}_dust,
where dot{M}_dust increases from Group I to II and III gradually. 17
S stars show the following properties: 1. two extrinsic S stars and
15 intrinsic S stars among different groups have different infrared
properties; 2. two extrinsic S stars and 6 intrinsic S stars in Group I
have similar ISO SWS01 spectra and their continua can be approximately
described by a single blackbody representing the stellar photosphere,
while some intrinsic S stars in Group I have 60 μm infrared excess;
3. for intrinsic S stars in Groups I, II, and III, their continua peak
shifts toward longer wavelength from Groups I to II to III; 4. S stars
in Groups II and III show obvious dust emission features in which the
10 μm dust features seem to display two different shapes. Moreover,
two S stars (IRAS 00192-2020 & IRAS 15492+4837) present the 13
μm feature; 5. molecules H{2}O, CO, and CO{2} greatly affect the ISO
SWS01 spectra of S stars. It is noted that the absorption features
of molecules CS and HCN usually thought to exist only in C stars may
appear in the S stars. Based on observations with ISO, an ESA
project with instruments funded by ESA Member States (especially the
PI countries: France, Germany, The Netherlands, and the United Kingdom)
with the participation of ISAS and NASA.
Title: Evolution of electron energy spectrum during solar flares
Authors: Liu, W. J.; Chen, P. F.; Fang, C.; Ding, M. D.
Bibcode: 2007AdSpR..39.1394L
Altcode:
Particle acceleration by direct current electric field in the current
sheet has been extensively studied, in which an electric and a magnetic
field are generally prescribed, and a power law distribution of the
electron energy is obtained. Based on MHD numerical simulations of
flares, this paper aims at investigating the time evolution of the
electron energy spectrum during solar flares. It turns out that the
model reproduces the soft-hard-hard spectral feature which was observed
in some flares.
Title: Seismic velocity variations on the San Andreas fault caused
by the 2004 M6 Parkfield Earthquake and their implications
Authors: Li, Y. -G.; Chen, P.; Cochran, E. S.; Vidale, J. E.
Bibcode: 2007EP&S...59...21L
Altcode:
Repeated earthquakes and explosions recorded at the San Andreas fault
(SAF) near Parkfield before and after the 2004 M6 Parkfield earthquake
show large seismic velocity variations within an approximately 200-
m-wide zone along the fault to depths of approximately 6 km. The
seismic arrays were co-sited in the two experiments and located
in the middle of a high-slip part of the surface rupture. Waveform
cross-correlations of microearthquakes recorded in 2002 and subsequent
repeated events recorded a week after the 2004 M6 mainshock show a
peak of an approximately 2.5% decrease in seismic velocity at stations
within the fault zone, most likely due to the co-seismic damage of
fault-zone rocks during dynamic rupture of this earthquake. The damage
zone is not symmetric; instead, it extends farther on the southwest
side of the main fault trace. Seismic velocities within the fault zone
measured for later repeated aftershocks in the following 3-4 months
show an approximate 1.2% increase at seismogenic depths, indicating
that the rock damaged in the mainshock recovers rigidity - or heals -
through time. The healing rate was not constant but was largest in
the earliest post-mainshock stage. The magnitude of fault damage and
healing varies across and along the rupture zone, indicating that the
greater damage was inflicted and thus greater healing is observed in
regions with larger slip in the mainshock. Observations of rock damage
during the mainshock and healing soon thereafter are consistent with
our interpretation of the low-velocity waveguide on the SAF being at
least partially softened in the 2004 M6 mainshock, with additional
cumulative effects due to recurrent rupture.
Title: Beam test of a prototype phoswich detector assembly for the
PoGOLite astronomical soft gamma-ray polarimeter
Authors: Kanai, Y.; Ueno, M.; Kataoka, J.; Arimoto, M.; Kawai, N.;
Yamamoto, K.; Mizuno, T.; Fukazawa, Y.; Kiss, M.; Ylinen, T.; Marini
Bettolo, C.; Carlson, P.; Klamra, W.; Pearce, M.; Chen, P.; Craig,
B.; Kamae, T.; Madejski, G.; Ng, J. S. T.; Rogers, R.; Tajima, H.;
Thurston, T. S.; Saito, Y.; Takahashi, T.; Gunji, S.; Bjornsson,
C. -I.; Larsson, S.; Ryde, F.; Bogaert, G.; Kishimoto, S.
Bibcode: 2007NIMPA.570...61K
Altcode:
We report about the beam test on a prototype of the balloon-based
astronomical soft gamma-ray polarimeter, PoGOLite (Polarized Gamma-ray
Observer Light Version) conducted at KEK Photon Factory, a synchrotron
radiation facility in Japan. The synchrotron beam was set at 30,
50, and 70 keV and its polarization was monitored by a calibrated
polarimeter. The goal of the experiment was to validate the flight
design of the polarimeter. PoGOLite is designed to measure polarization
by detecting a Compton scattering and the subsequent photo-absorption
in an array of 217 well-type phoswich detector cells (PDCs). The test
setup included a first flight model PDC and a front-end electronics to
select and reconstruct valid Compton scattering events. The experiment
has verified that the flight PDC can detect recoil electrons and select
valid Compton scattering events down to 30 keV from background. The
measure azimuthal modulations (34.4%, 35.8% and 37.2% at 30, 50, and 70
keV, respectively) agreed within 10% (relative) with the predictions
by Geant4 implemented with dependence on the initial and final photon
polarizations.
Title: Magnetic reconnection configurations and particle acceleration
in solar flares
Authors: Chen, P. F.; Liu, W. J.; Fang, C.
Bibcode: 2007AdSpR..39.1421C
Altcode:
Numerical simulations of two types of flares indicate that magnetic
reconnection can provide environments favorable for various particle
acceleration mechanisms to work. This paper reviews recent test particle
simulations of DC electric field mechanism, and discusses how the flare
particles can escape into the interplanetary space under different
magnetic configurations.
Title: Transition-Region Explosive Events: Reconnection Modulated
by p-Mode Waves
Authors: Chen, P. F.; Priest, E. R.
Bibcode: 2006SoPh..238..313C
Altcode: 2006SoPh..tmp...61C
Transition-region explosive events (TREEs) have long been proposed
as a consequence of magnetic reconnection. However, several critical
issues have not been well addressed, such as the location of the
reconnection site, their unusually short lifetime (about one minute),
and the recently discovered repetitive behaviour with a period of three
to five minutes. In this paper, we perform MHD numerical simulations
of magnetic reconnection, where the effect of five-minute solar p-mode
oscillations is examined. UV emission lines are synthesised on the
basis of numerical results in order to compare with observations
directly. It is found that several typical and puzzling features of
the TREEs with impulsive bursty behaviour can only be explained if
there exist p-mode oscillations and the reconnection site is located
in the upper chromosphere at a height range of around 1900 km < h
< 2150 km above the solar surface. Furthermore, the lack of proper
motions of the high-velocity ejection may be due to a rapid change of
temperature along the reconnection ejecta.
Title: Two Successive Coronal Mass Ejections Driven by the Kink and
Drainage Instabilities of an Eruptive Prominence
Authors: Zhou, G. P.; Wang, J. X.; Zhang, J.; Chen, P. F.; Ji, H. S.;
Dere, K.
Bibcode: 2006ApJ...651.1238Z
Altcode:
We describe a clear case of the initiation of a propagating bright arc
and a CME on 2002 December 28, which were associated with an eruptive
prominence. In EIT 304 and 195 Å images, a very long filament showed
evidence of severe twisting in one of its fragments, which appeared as a
prominence on December 26; then, the prominence showed the conversion of
its twist into writhe. Two days later, the prominence displayed a slow
rising motion for hours. Internal twisting and mass motion took place
before the rapid acceleration and final eruption. The propagating bright
arc and the following CME corresponded to the early rising and the
subsequently eruptive phases of the prominence, respectively. Signatures
of magnetic reconnection, i.e., a cusp structure and postflare loops
in EUV wave bands and hard X-ray sources in the corona, were observed
after the prominence eruption. It appears that the kink instability
and the mass drainage in the prominence played key roles in triggering
the initiation of the CME. However, the rather impulsive acceleration
of the CME resulted from magnetic reconnection beneath the filament.
Title: On the CME velocity distribution
Authors: Chen, A. Q.; Chen, P. F.; Fang, C.
Bibcode: 2006A&A...456.1153C
Altcode:
Context: .Coronal mass ejections (CMEs) are often categorized into
flare-associated and filament-associated types, which logically is
incomplete since there are many CMEs of the intermediate type.
Aims: .With this new classification, this paper aims to reexamine
whether flare-associated CMEs and filament eruption-associated
CMEs have distinct velocity distributions and to investigate which
factors may affect the CME velocities.
Methods: .We divide
the CME events observed from 2001-2003 into three types, i.e., the
flare-associated type, the filament eruption-associated type, and the
intermediate type. The magnetic environments of the source regions,
e.g., the polarity orientation, the chirality of the filaments, etc.,
are examined.
Results: .Our results indicate that the P-value
of the likelihood between the flare-associated and the filament
eruption-associated CMEs is as high as 0.79, which strongly suggests
that they are a continuum of events rather than two distinct types. For
the filament eruption-associated CMEs, the speeds are found to be
strongly correlated with the average magnetic field in the filament
channel. It is also found that there is a slight tendency for the
filaments with the minority chirality to have weaker magnetic fields,
and hence the corresponding CMEs have smaller eruption speeds. A slight
tendency is also found for the CMEs associated with non-active region
filaments to have higher eruption speeds than those with active region
filaments. However, the polarity orientation of the filament channel
has little effect on the eruption speed.
Title: Spectral Analysis of Ellerman Bombs
Authors: Fang, C.; Tang, Y. H.; Xu, Z.; Ding, M. D.; Chen, P. F.
Bibcode: 2006ApJ...643.1325F
Altcode:
By use of the high-resolution spectral data obtained with THEMIS on
2002 September 5, the characteristics of 14 well-observed Ellerman
bombs (EBs) have been analyzed. Our results indicate that 9 of the
14 EBs are located near the longitudinal magnetic polarity inversion
lines. Most of the EBs are accompanied by mass motions. The most obvious
characteristic of the EB spectra is the two emission bumps at the two
wings of both Hα and Ca II λ8542. For the first time both thermal
and nonthermal semiempirical atmospheric models for the conspicuous
and faint EBs are computed. In computing the nonthermal models, we
assume that the electron beam resulting from magnetic reconnection is
produced in the lower chromosphere. The reasons are that it requires
much lower energies for the injected particles and that it gives rise
to a more profound absorption at the Hα line center, in agreement with
our observations. The common characteristic is the heating in the lower
chromosphere and the upper photosphere. The temperature enhancement
is about 600-1300 K in the thermal models. If the nonthermal effects
are included, then the required temperature increase can be reduced
by 100-300 K. These imply that the EBs could probably be produced by
the magnetic reconnection in the solar lower atmosphere. The radiative
and kinetic energies of the EBs are estimated, and the total energy
is found to be 1026 to 5×1027 ergs. According
to the characteristics of EBs, we tentatively suggest that EBs could
be called ``submicroflares.''
Title: Optically Scaled Occulter Data Analysis
Authors: Jordan, Ian J. E.; Henze, P.; Sauter, G.; Hart, H. M.;
Schultz, A. B.; Kochte, M.; Chen, P.; Cash, W.
Bibcode: 2006AAS...208.5603J
Altcode: 2006BAAS...38..136J
We present a detailed analysis of results of an optically scaled
external occulter system. The display describes the optical scaling
and the results of WASI-UMBRAS occulter tests performed at Fresnel
numbers of 10 and 40 since August of 2004.
Title: The Relation between EIT Waves and Solar Flares
Authors: Chen, P. F.
Bibcode: 2006ApJ...641L.153C
Altcode:
In order to determine whether EIT waves are generated by coronal
mass ejections (CMEs) or pressure pulses in solar flares, 14
non-CME-associated energetic flares, which should possess strong
pressure pulses in their loops, are studied. They are selected near
solar minimum, as this favors the detection of EIT waves. It is found
that none of these flares are associated with EIT waves. Particular
attention is paid to AR 0720, which hosted both CME-associated and
non-CME types of flares. The SOHO/EIT images convincingly indicate
that EIT waves and expanding dimmings appear only when CMEs are
present. Therefore, it is unlikely that pressure pulses from flares
generate EIT waves.
Title: Measurement of pressure dependent fluorescence yield of air:
Calibration factor for UHECR detectors
Authors: FLASH Collaboration; Belz, J. W.; Burt, G. W.; Cao, Z.; Chang,
F. Y.; Chen, C. C.; Chen, C. W.; Chen, P.; Field, C.; Findlay, J.;
Hüntemeyer, P.; Huang, M. A.; Hwang, W. -Y. P.; Iverson, R.; Jones,
B. F.; Jui, C. C. H.; Kirn, M.; Lin, G. -L.; Loh, E. C.; Maestas,
M. M.; Manago, N.; Martens, K.; Matthews, J. N.; Ng, J. S. T.; Odian,
A.; Reil, K.; Smith, J. D.; Snow, R.; Sokolsky, P.; Springer, R. W.;
Thomas, J. R.; Thomas, S. B.; Thomson, G. B.; Walz, D.; Zech, A.
Bibcode: 2006APh....25..129F
Altcode: 2005astro.ph..6741F; 2006APh....25..129C
In a test experiment at the Final Focus Test Beam of the Stanford
Linear Accelerator Center, the fluorescence yield of 28.5
GeV electrons in air and nitrogen was measured. The measured
photon yields between 300 and 400 nm at 1 atm and 29 °C are
Y(760Torr)=4.42±0.73andY(760Torr)=29.2±4.8
photons per electron per meter. Assuming that the fluorescence yield is
proportional to the energy deposition of a charged particle traveling
through air, good agreement with measurements at lower particle energies
is observed.
Title: Comparison of air fluorescence and ionization measurements
of EM shower depth profiles: Test of a UHECR detector technique
Authors: Belz, J.; Cao, Z.; Huentemeyer, P.; Jui, C. C. H.; Martens,
K.; Matthews, J.; Maestas, M.; Smith, J.; Sokolsky, P.; Springer,
R. W.; Thomas, J.; Thomas, S.; Chen, P.; Field, C.; Hast, C.; Iverson,
R.; Ng, J. S. T.; Odian, A.; Reil, K.; Vincke, H.; Walz, D.; Goldammer,
A.; Guest, D.; Thomson, G.; Chang, F. -Y.; Chen, C. -C.; Chen, C. -W.;
Huang, M. A.; Hwang, W. -Y. P.; Lin, G. -L.
Bibcode: 2006APh....25...57B
Altcode: 2005astro.ph.10375B
Measurements are reported on the fluorescence of air as a function
of depth in electromagnetic showers initiated by bunches of 28.5 GeV
electrons. The light yield is compared with the expected and observed
depth profiles of ionization in the showers. It validates the use
of atmospheric fluorescence profiles in measuring ultra high energy
cosmic rays.
Title: Two candidate homologous CMEs on 2002 May 22
Authors: Cheng, J. X.; Fang, C.; Chen, P. F.
Bibcode: 2006AdSpR..38..470C
Altcode:
Two coronal mass ejections (CMEs) occurred on 2002 May 22, originating
from the same active region, AR 9948. Multi-wavelength data are
collected in order to clarify the relationship between the CMEs,
the associated flares and filament eruptions, and some other magnetic
activities, which is of great importance to understand the mechanism
of each phenomenon. It is tentatively suggested that the two CMEs are
probably homologous.
Title: Altitude Dependence of Hard X-Ray Spectra in Solar Flares
Authors: Chen, Q. R.; Ding, M. D.; Chen, P. F.
Bibcode: 2006IAUS..233..177C
Altcode:
We investigate the altitude dependence of hard X-ray (HXR) spectra in
solar flares, i.e., whether the HXR spectra are related to the altitudes
of reconnection sites. We assume that the reconnection altitude can
be scaled by the distance between the two conjugate HXR footpoints in
the flare. By searching the RHESSI flare list from 2002 to 2004, we
find 42 solar flares below X-class that have enhanced 50-100 keV HXR
emission and two well-resolved HXR footpoints at the nonthermal peak
time. The preliminary results show that there is a weak correlation
(∼ -0.31) between the HXR spectral index and the HXR footpoint
distance. We further discuss the possible implications.
Title: Why are there stationary EIT wave fronts
Authors: Chen, P. F.; Fang, C.; Shibata, K.
Bibcode: 2006AdSpR..38..456C
Altcode:
EIT waves are often observed to be propagating EUV enhancements followed
by an expanding dimming region after the launch of CMEs. It was widely
assumed that they are the coronal counterparts of the chromospheric
Moreton waves, though the former are three or more times slower. The
existence of a stationary “EIT wave” front in some events,
however, posed a big challenge to the wave explanation. Simulations
are performed to reproduce the stationary “EIT wave” front, which
is exactly located near the footpoint of the magnetic separatrix,
consistent with observations. The formation of the stationary front
is explained in the framework of our model where “EIT waves” are
supposed to be generated by successive opening of the field lines
covering the erupting flux rope in CMEs.
Title: CMEs driven by an eruptive prominence
Authors: Zhou, G. P.; Wang, J. X.; Zhang, J.; Chen, P. F.; Ji, H. S.;
Dere, K.
Bibcode: 2006IAUS..233..405Z
Altcode:
A clear case on Dec. 28 2002 is presented. It is about the initiation of
two successive CMEs, which were related to an eruptive prominence. In
EIT 304 Å and 195 Å observations, we found a long filament severely
twisting in a piece of its fragments, which appeared as a prominence on
Dec. 26. Then, the prominence converted its twist into writhe. Two days
later, the prominence displayed a slow rising motion for hours. There
happened internal twisting and mass motion before the prominence rapid
acceleration and final eruption. Two successive CMEs recorded by LASCO
C2 coronagraph corresponded to the early rising and the subsequently
eruptive phases of the prominence, respectively. Evidence of magnetic
reconnection, i.e., a cusp structure and post-flare loops in EUV
wavebands, and hard X-ray sources in the corona, were observed after
the prominence disruption. It appears that the kink instability and the
mass drainage in the prominence played important roles in triggering two
CMEs' initiation. We suspected that the rather impulsive acceleration
of the second CME resulted from magnetic reconnection beneath the
prominence.
Title: Relation between the CME Velocity and the Magnetic Field
Authors: Chen, A. Q.; Chen, P. F.; Fang, C.
Bibcode: 2006cosp...36..426C
Altcode: 2006cosp.meet..426C
The velocities of Coronal mass ejections CMEs range from tens to more
than 2000 km s Earlier researches tended to fit them into a bimodal
distribution with the fast ones corresponding to flares and the slow
ones to filament eruptions However recent observations do not favor
such a classification and tend to imply that magnetic reconnection
plays an important role in the eruption of CMEs According to the
reconnection model the velocity of the ejecta is proportional to the
magnetic field strength in the inflow region We present a statistical
analysis of CME speeds with relation to the magnetic parameters It
is found that the CME velocity correlation with the average magnetic
field is significantly higher than with the total magnetic flux in
the source region It is also seen that filaments with the minority
chirality tend to erupt as slow CMEs
Title: Self-consistent MHD modeling of a coronal mass ejection,
coronal dimming, and a giant cusp-shaped arcade formation
Authors: Shiota, D.; Isobe, H.; Chen, P. F.; Yamamoto, T. T.; Sakajiri,
T.; Shibata, K.
Bibcode: 2006cosp...36.1994S
Altcode: 2006cosp.meet.1994S
Coronal mass ejections CMEs are one of the most spectacular phenomena in
the solar corona Recent observations revealed that CMEs are associated
with either solar flares or giant arcade formations in which magnetic
reconnection is thought to play an essential role Considering these
observations Shibata 1996 1999 suggest that CMEs filament eruptions
flares giant arcades can be understood in a unified view mass ejection
and magnetic energy release via magnetic reconnection We performed
magnetohydrodynamic simulations of CMEs and associated giant arcade
formations The soft X-ray images synthesized from the numerical
results are compared with the soft X-ray images taken with the Soft
X-Ray Telescope aboard Yohkoh The comparison between synthesized and
observed soft X-ray images provides new interpretations of various
features associated with CMEs and giant arcades 1 It is likely that
the Y-shaped ejecting structure observed in the giant arcade on 1992
January 24 corresponds to slow and fast shocks associated with magnetic
reconnection 2 Soft X-ray twin dimming corresponds to the rarefaction
induced by reconnection 3 The inner boundary of the dimming region
corresponds to the slow shocks 4 The three-part structure of a CME
can be explained by our numerical results 5 The numerical results
also suggest that a backbone feature of a flare giant arcade may
correspond to the fast shock formed by the collision of the downward
reconnection outflow
Title: EUV signatures of the CME propagation: from SOHO to KuaFu A
Authors: Chen, P. F.
Bibcode: 2006cosp...36.3210C
Altcode: 2006cosp.meet.3210C
Observations of the early evolution of CMEs are extremely important
since they can provide not only the information about the direct link
between the large-scale eruptions and the small-scale flares but also
the warnings of the forthcoming space weather disturbances especially
the earth-directed CMEs With the discovery of EIT waves SOHO EIT turned
out to a success in monitoring the initiation phase of CMEs Based on
MHD simulations of the CMEs we reproduced the slowly propagating EIT
waves and expanding dimmings in the synthesized Fe XII 195A images EUV
images of the CME initiation at other wavelengths are also synthesized
with the aim to select the most suitable observing band for the EDI
instrument to be aboard Kuafu A
Title: Statistical study of filament eruptions with emerging flux
Authors: Xu, X. Y.; Fang, C.; Chen, P. F.; Ding, M. D.
Bibcode: 2006cosp...36.1148X
Altcode: 2006cosp.meet.1148X
Observations indicate that solar coronal mass ejections CMEs are
closely associated with reconnection-favored flux emergence which
was explained in the emerging flux trigger mechanism for CMEs by Chen
Shibata 2000 Using numerical simulations we made a parametric survey
of the triggering factors the polarity orientation and the position
of the emerging flux and the amount of the unsigned flux Xu Chen Fang
2005 A diagram is presented to show the eruption and non-eruption
regimes in the parameter space In this paper a statistical study on
the filament eruptions related to emerging flux is performed and it
basically supports the theoretical results of our numerical simulation
Our results suggest that whether a CME can be triggered depends on
both the amount and the location of an emerging flux in addition to
its polarity orientation The work provides useful information for the
space weather forecast
Title: Magnetic reconnection and electron acceleration in the solar
lower atmosphere
Authors: Fang, C.; Xu, X. Y.; Chen, P. F.
Bibcode: 2006cosp...36..203F
Altcode: 2006cosp.meet..203F
Using high-resolution spectral data obtained with THEMIS on 2002
September 5 we have computed the semi-empirical atmospheric models of
Ellerman bombs EBs and microflares MFs Our results indicate that for
both of them there is a temperature bump up in the low-chromosphere
Compared to the quiet-Sun atmosphere the temperature bump up of the
bright MFs is about 2200K while that of the conspicuous EBs is about
1300K and locates deeper than that for MFs The temperature bump up can
be produced by the magnetic reconnection in the solar lower atmosphere
Assuming electrons being accelerated during the magnetic reconnection
we computed the non-thermal semi-empirical atmospheric models of EBs
and MFs which can well reproduce the observed H alpha and CaII 8542
AA lines The parameters and the energy deposit of the electron beams
have been discussed
Title: Ellerman Bombs: Sub-Microflares in the Solar Atmosphere
Authors: Fang, C.; Tang, Y. H.; Xu, Z.; Ding, M. D.; Chen, P. F.
Bibcode: 2006apri.meet...32F
Altcode:
No abstract at ADS
Title: Magnetic reconnection configurations and particle accelerations
on the Sun
Authors: Chen, P. F.; Liu, W. J.; Fang, C.
Bibcode: 2006cosp...36.3345C
Altcode: 2006cosp.meet.3345C
The electric field near the small-scale reconnection site has been
suggested to be a plausible mechanism for the nonthermal particles
that produce type III radio bursts and hard X-ray emissions in the
corona and chromosphere It has been demonstrated that the magnetic
configuration near the reconnection site plays an important role in
determining the final energy spectrum of the particles In this paper we
first review different reconnection configurations in the Sun which are
associated with various eruptive phenomena such as two-ribbon flares
emerging flux coronal loop-loop interactions and so on We then perform
test particle simulations with these magnetic configurations in order
to investigate their effect on the energy spectrum of the accelerated
particles Their application to observations is discussed
Title: Investigation of Electron Energy Spectrum During Solar Flares
Authors: Liu, W. J.; Chen, P. F.; Fang, C.; Ding, M. D.
Bibcode: 2006cosp...36.2650L
Altcode: 2006cosp.meet.2650L
Observations indicated that the energy spectrum of non-thermal
particles during the evolution of solar flares changes rapidly with
the power index alternating from soft to hard and soft again Based on
MHD numerical simulation of a flare with the typical prephase impulsive
and decay phases we perform the test-particle simulations in order to
investigate the time evolution of the electron spectrum The results
are compared with observations in detail
Title: A Parametric Survey of the CME Triggering Process by Numerical
Simulations
Authors: Xu, Xiao-Yan; Chen, Peng-Fei; Fang, Cheng
Bibcode: 2005ChJAA...5..636X
Altcode:
Observations indicate that solar coronal mass ejections (CMEs) are
closely associated with reconnection-favored flux emergence, which
was explained in the emerging flux trigger mechanism for CMEs by Chen
& Shibata based on numerical simulations. We present a parametric
survey of the triggering agent: its polarity orientation, position,
and the amount of the unsigned flux. The results suggest that whether
a CME can be triggered depends on both the amount and location of the
emerging flux, in addition to its polarity orientation. A diagram
is presented to show the eruption and non-eruption regimes in the
parameter space. The work is aimed at providing useful information
for the space weather forecast.
Title: Simple analytical models of gravitational collapse
Authors: Adler, R. J.; Bjorken, J. D.; Chen, P.; Liu, J. S.
Bibcode: 2005AmJPh..73.1148A
Altcode: 2005gr.qc.....2040A
Most general relativity textbooks devote considerable attention to
the simplest example of a black hole containing a singularity, the
Schwarzschild geometry. Only a few discuss the dynamical process of
gravitational collapse by which black holes and singularities form. We
present two simple analytical models that describe this process. The
first involves collapsing spherical shells of light and is analyzed
mainly in Eddington-Finkelstein coordinates; the second involves
collapsing spheres filled with a perfect fluid and is analyzed mainly
in Painleve-Gullstrand coordinates. Our main goal is simplicity and
algebraic completeness, but we also present a few more sophisticated
results such as the collapse of a light shell in Kruskal-Szekeres
coordinates.
Title: Direct EIT Observations of a Prominence-Associated CME
Initiation With the Kink and Drainage Instabilities
Authors: Zhou, G.; Wang, J.; Chen, P.; Zhang, J.; Pu, Z.
Bibcode: 2005AGUFMSH12A..04Z
Altcode:
We found a clear case to show the onset phase of two successive
CMEs associated with an eruptive prominence on Dec. 28 2002. The
prominence(~137000 km in length) presented twist for three circles
before its upward motion; then converted its twist to writhing
helicity with kink-instability; and last disrupted because of
drainage instability. Following the eruption, two successive
associated CMEs first appeared at 13:54 UT and 16:30 UT in LASCO
C2 images, respectively, and the attendant phenomenon a cusp shape
structure and post-flare loop were observed. This evidence partially
supports the flux rope model and flux rope instability model, but
unlike previous studies, the prominence eruption itself has all the
observable characteristics of the kink and drainage instability from
the direct EIT observations. And magnetic reconnection was just an
attendant phenomena after the prominence disruption that might only
attribute to the CMEs' acceleration out of 8 R?. The associated CMEs
are suggested to come from the energized overlaying arcades driven by
the eruptive prominence with kink and drainage instability.
Title: Synthesis of CME-Associated Moreton and EIT Wave Features
from MHD Simulations
Authors: Chen, P. F.; Ding, M. D.; Fang, C.
Bibcode: 2005SSRv..121..201C
Altcode:
Soft X-ray (SXR) waves, EIT waves, and Hα Moreton waves are all
associated with coronal mass ejections (CMEs). The knowledge of the
characteristics about these waves is crucial for the understanding
of CMEs, and hence for the space weather researches. MHD numerical
simulation is performed, with the consideration of the quiet Sun
atmosphere, to investigate the CME/flare processes. On the basis of
the numerical results, SXR, EUV, and Hα images of the eruption are
synthesized, where SXR waves, EIT waves, and Hα Moreton waves are
identified. It confirms that the EIT waves, which border the expanding
dimmming region, are produced by the successive opening (or stretching)
of the closed magnetic field lines. Hα Moreton waves are found to
propagate outward synchronously with the SXR waves, lagging behind
the latter spatially by ∼27 Mm in the simulated scenario. However,
the EIT wave velocity is only a third of the Moreton wave velocity. The
synthesized results also suggest that Hα± 0.45Å would be the best
off-band for the detection of Hα Moreton waves.
Title: Self-Consistent Magnetohydrodynamic Modeling of a Coronal Mass
Ejection, Coronal Dimming, and a Giant Cusp-shaped Arcade Formation
Authors: Shiota, Daikou; Isobe, Hiroaki; Chen, P. F.; Yamamoto,
Tetsuya T.; Sakajiri, Takuma; Shibata, Kazunari
Bibcode: 2005ApJ...634..663S
Altcode: 2005astro.ph..8478S
We performed magnetohydrodynamic simulations of coronal mass ejections
(CMEs) and associated giant arcade formations, and the results suggest
new interpretations of observations of CMEs. We performed two cases of
the simulation: with and without heat conduction. Comparing between
the results of the two cases, we found that the reconnection rate
in the conductive case is a little higher than that in the adiabatic
case and that the temperature of the loop top is consistent with the
theoretical value predicted by the Yokoyama-Shibata scaling law. The
dynamical properties such as velocity and magnetic field are similar
in the two cases, whereas thermal properties such as temperature and
density are very different. In both cases, slow shocks associated
with magnetic reconnection propagate from the reconnection region
along the magnetic field lines around the flux rope, and the shock
fronts form spiral patterns. Just outside the slow shocks, the plasma
density decreases greatly. The soft X-ray images synthesized from
the numerical results are compared with the soft X-ray images of a
giant arcade observed with the Soft X-Ray Telescope aboard Yohkoh;
it is confirmed that the effect of heat conduction is significant
for the detailed comparison between simulation and observation. The
comparison between synthesized and observed soft X-ray images provides
new interpretations of various features associated with CMEs and
giant arcades. (1) It is likely that the Y-shaped ejecting structure,
observed in the giant arcade on 1992 January 24, corresponds to slow and
fast shocks associated with magnetic reconnection. (2) Soft X-ray twin
dimming corresponds to the rarefaction induced by reconnection. (3)
The inner boundary of the dimming region corresponds to the slow
shocks. (4) The ``three-part structure'' of a CME can be explained by
our numerical results. (5) The numerical results also suggest that a
backbone feature of a flare/giant arcade may correspond to the fast
shock formed by the collision of the downward reconnection outflow.
Title: Low energy response of a prototype detector array for the
PoGO astronomical hard x-ray polarimeter
Authors: Kataoka, J.; Kanai, Y.; Arimoto, M.; Ikagawa, T.; Saito, T.;
Ueno, M.; Kawai, N.; Blandford, R.; Chen, P.; Kamae, T.; Madejski, G.;
Mizuno, T.; Ng, J.; Tajima, H.; Thurston, T.; Barbier, L.; Harding,
A.; Krizmanic, J.; Hunter, S.; Mitchell, J.; Streitmatter, R.; Groth,
E.; Fernholtz, R.; Marlow, D.; Saito, Y.; Takahashi, T.; Gunji, S.;
Sakurai, H.; Fukazawa, Y.; Anderson, V.; Carlson, P.; Klamra, W.;
Pearce, M.; Suhonen, M.; Larsson, S.; Ryde, F.; Bjornsson, C. -I.;
Bogaert, G.; Kishimoto, S.
Bibcode: 2005SPIE.5898..133K
Altcode:
The Polarized Gamma-ray Observer (PoGO) is a new balloon-borne
instrument designed to measure polarization from astrophysical objects
in the 30-200 keV range. It is under development for the first flight
anticipated in 2008. PoGO is designed to minimize the background by
an improved phoswich configuration, which enables a detection of 10
% polarization in a 100 mCrab source in a 6--8 hour observation. To
achieve such high sensitivity, low energy response of the detector
is important because the source count rate is generally dominated
by the lowest energy photons. We have developed new PMT assemblies
specifically designed for PoGO to read-out weak scintillation light of
one photoelectron (1 p.e.) level. A beam test of a prototype detector
array was conducted at the KEK Photon Factory, Tsukuba in Japan. The
experimental data confirm that PoGO can detect polarization of 80-85 %
polarized beam down to 30 keV with a modulation factor 0.25 +/- 0.05.
Title: Kinetic Properties of CMEs Corrected for the Projection Effect
Authors: Yeh, Chin-Teh; Ding, M. D.; Chen, P. F.
Bibcode: 2005SoPh..229..313Y
Altcode:
Observations of coronal mass ejections (CMEs) with coronagraphs are
subject to a projection effect, which results in statistical errors in
many properties of CMEs, such as the eruption speed and the angular
width. In this paper, we develop a method to obtain the velocity and
angular width distributions of CMEs corrected for the projection
effect, and then re-examine the relationship between CMEs and the
associated flares. We find that (1) the mean eruption speed is 792
km s−1 and the mean angular width is 59∘,
compared to the values of 549 km s−1 and 77∘,
respectively before the correction; (2) after the correction, the
weak correlation between CME speeds and the GOES X-ray peak flux of
the flares gets unexpectedly poorer; and (3) before correction, there
is a weak correlation between the angular width and the speed of CMEs,
whereas the correlation is absent after the correction.
Title: Two Sympathetic Homologous CMEs on 2002 May 22
Authors: Cheng, Jian-Xia; Fang, Cheng; Chen, Peng-Fei; Ding, Ming-De
Bibcode: 2005ChJAA...5..265C
Altcode:
Sympathetic coronal mass ejections (CMEs) usually occur in different
active regions connected by interconnecting magnetic loops, while
homologous CMEs occur within the same active region with an almost
the same background magnetic field, and so are similar in shapes. Two
sympathetic CMEs erupted within 3 hours on 2002 May 22, originating
from the same active region, AR 9948. Their multi-wavelength data were
collected and analyzed. It is suggested that emerging flux triggered
the occurrence of the first CME and the corresponding flare, the
reconnection inflow of which in turn triggered the eruption of the
second CME. Based on the fact that the two sympathetic CMEs have
many similarities, in their shapes, their low-lying dimming areas,
etc., we tentatively propose, for the first time, the phenomenon of
sympathetic homologous CMEs.
Title: Erratum
Authors: Chen, P. -F.; Bina, C. R.; Okal, E. A.
Bibcode: 2005GeoJI.161..419D
Altcode:
No abstract at ADS
Title: Waiting Time Distribution of Coronal Mass Ejections
Authors: Yeh, Chin-Teh; Ding, Ming-De; Chen, Peng-Fei
Bibcode: 2005ChJAA...5..193Y
Altcode:
Inspired by the finding that the large waiting time of solar flares
presents a power-law distribution, we investigate the waiting time
distribution (WTD) of coronal mass ejections (CMEs). SOHO/LASCO CME
observations from 1996 to 2003 are used in this study. It is shown that
the observed CMEs have a similar power-law behavior to the flares,
with an almost identical power-law index. This strongly supports the
viewpoint that solar flares and CMEs are different manifestations of
the same physical process. We have also investigated separately the
WTDs of fast-type and slow-type CMEs and found that their indices are
identical, which imply that both types of CME may originate from the
same physical mechanism.
Title: A Full View of EIT Waves
Authors: Chen, P. F.; Fang, C.; Shibata, K.
Bibcode: 2005ApJ...622.1202C
Altcode:
Early observations by the EUV Imaging Telescope (EIT) on the Solar and
Heliospheric Observatory indicated that propagating diffuse wave fronts,
now conventionally referred to as ``EIT waves,'' can often be seen on
the solar disk with a propagation velocity several times smaller than
that of Hα Moreton waves. They are almost always associated with
coronal mass ejections. We have previously confirmed the existence
of such a wave phenomenon with numerical simulations, which indicate
that there does exist a slower moving ``wave'' much behind the coronal
counterpart of the Hα Moreton wave. Further observations have disclosed
many new features of the EIT waves: the waves stop near the separatrix
between active regions, sometimes they experience acceleration from
the active region to the quiet region, and so on. Here we report on
MHD simulations performed to demonstrate how the typical features of
EIT waves can all be accounted for within our theoretical model, in
which the EIT waves are thought to be formed by successive stretching
or opening of closed field lines driven by an erupting flux rope. The
relationship between EIT waves, Hα Moreton waves, and type II radio
bursts is discussed, with an emphasis on reconciling the discrepancies
among different views of the ``EIT wave'' phenomenon.
Title: Parametric Survey of Emerging Flux for Triggering CMEs
Authors: Xu, X. Y.; Chen, P. F.; Fang, C.; Ding, M. D.
Bibcode: 2005IAUS..226..217X
Altcode:
Observations suggest that solar coronal mass ejections (CMEs) are
closely associated with reconnection-favored flux emergence, which
was explained as the emerging flux trigger mechanism for CMEs by Chen
and Shibata (2000) based on numerical simulations. This paper presents
a parametric survey of the CME-triggering environment. Our numerical
results show that whether the CMEs can be triggered depends on both
the amount and the location of the emerging flux. The results are
useful for space weather forecast.
Title: A Reconsideration of the Classification of Two Types of CMEs
Authors: Chen, A. Q.; Yeh, C. T.; Cheng, J. X.; Chen, P. F.
Bibcode: 2005IAUS..226..110C
Altcode:
Conventionally coronal mass ejections (CMEs) are categorized into
flare-associated and filament-associated types. Since there are also
many CMEs of the overlapping type, we classify CMEs into three types
in order to compare their characteristics. It is found that the three
types of CMEs have quite similar distributions of apparent speeds,
with small difference in the average speeds.
Title: EIT waves -- A signature of global magnetic restructuring
in CMEs
Authors: Chen, P. F.; Fang, C.
Bibcode: 2005IAUS..226...55C
Altcode:
The discovery of "EIT waves" after the launch of SOHO spacecraft sparked
wide interest among the coronal mass ejection (CME) community since
they may be crucial to the understanding of CMEs. However, the nature
of this phenomenon is still being hotly debated between fast-mode wave
explanation and non-wave explanation. Accumulating observations have
shown various features of the "EIT waves". For example, they tend to
be devoid of magnetic neutral lines and coronal holes; they may stop
near the magnetic separatrix between the source region and a nearby
active region; they may experience an acceleration from the vicinity of
the source active region to the quiet region, and so on. This paper is
aimed to review all these features, discuss how these observations may
provide constraints for the theoretical models, and point out their
implication to the understanding of CMEs.
Title: Large-Area Balloon-Borne Polarized Gamma Ray Observer (PoGO)
Authors: Andersson, V.; Chen, P.; Kamae, T.; Madejski, G.; Mizuno,
T.; Ng, J. S. T.; Suhonen, M.; Tajima, H.; Thurston, T.; Bogaert,
G.; Fukazawa, Y.; Saito, Y.; Takahashi, T.; Barbier, L.; Bloser,
P.; Cline, T.; Harding, A.; Hunter, S.; Krizmanic, J.; Mitchell, J.;
Streitmatter, R.; Fernholz, R.; Groth, E.; Marlow, D.; Carlson, P.;
Klamra, W.; Pearce, M.; Bjornsson, C. -I.; Fransson, C.; Larsson, S.;
Ryde, F.; Arimoto, M.; Ikagawa, T.; Kanai, Y.; Kataoka, J.; Kawai,
N.; Yatsu, Y.; Gunji, S.; Sakurai, H.; Yamashita, Y.
Bibcode: 2005tsra.conf..736A
Altcode:
We are developing a new balloon-borne instrument (PoGO), to measure
polarization of soft gamma rays (30-200 keV) using asymmetry in azimuth
angle distribution of Compton scattering. PoGO is designed to detect 10
% polarization in 100mCrab sources in a 6-8 hour observation and bring a
new dimension to studies on gamma ray emission/transportation mechanism
in pulsars, AGNs, black hole binaries, and neutron star surface. The
concept is an adaptation to polarization measurements of well-type
phoswich counter consisting of a fast plastic scintillator (the
detection part), a slow plastic scintillator (the active collimator)
and a BGO scintillator (the bottom anti-counter). PoGO consists
of close-packed array of 217 hexagonal well-type phoswich counters
and has a narrow field-of-view (~ 5 deg2) to reduce possible source
confusion. A prototype instrument has been tested in the polarized soft
gamma-ray beams at Advanced Photon Source (ANL) and at Photon Factory
(KEK). On the results, the polarization dependence of EGS4 has been
validated and that of Geant4 has been corrected.
Title: Measurements of the Fluorescence Light Yield in Electromagnetic
Showers
Authors: Reil, K.; Chen, P.; Field, C.; Hast, C.; Iverson, R.; Ng,
J. S. T.; Odian, A.; Vincke, H.; Walz, D.; Belz, J.; Goldammer, A.;
Guest, D.; Bergman, D. R.; Cavanaugh, S.; Perera, L.; Schnetzer, S.;
Thomson, G. B.; Zech, A.; Cao, Z.; Huentemeyer, P.; Jui, C. C. H.;
Loh, E. C.; Martens, K.; Matthews, J. N.; Smith, J. D.; Sokolsky,
P.; Springer, R. W.; Thomas, S. B.; Chang, F. Y.; Chen, C. C.; Chen,
C. W.; Huang, M. A.; Hwang, W. -Y. P.; Lin, G. -L.
Bibcode: 2005tsra.conf..712R
Altcode:
The two most common methods of determining the energy of an ultra
high energy cosmic ray (UHECR) are ground arrays and fluorescence
telescopes. Ground array detectors determine energy by sampling the
number of shower particles arriving at the surface of the earth. In
general, the more particles, the higher the energy. Fluorescence
telescopes, on the other hand, determine the energy by measuring
the number of ultraviolet photons produced by the electromagnetic
shower produced in the atmosphere. The number of photons is related
to the number of particles in the shower by the fluorescence yield
(measured in photons per meter per charged particle). The Akeno Giant
Air Shower Array (AGASA) and the High Resolution Flys Eye (HiRes) are
the current world leading ground array and fluorescence detectors,
respectively. Recent results from the two experiments indicate a
significant discrepancy in the flux of cosmic rays as a function of
energy[1―3 ]. This indicates that there may be a systematic offset
in energy determination in the two techniques. The FLuorescence in Air
from SHowers (FLASH) experiment is an effort to reduce the systematic
uncertainty in energy determination for fluorescence detectors by
making an improved measurement of the fluorescence yield. This work
is intended to add to the prior work of Bunner, Kakimoto et al. and
Nagano et al.[4―7]. We report on the current status of the experiment.
Title: Waiting Time Distribution of CMES
Authors: Yeh, C. -T.; Ding, M. D.; Chen, P. F.
Bibcode: 2005ASSL..320..171Y
Altcode: 2005smp..conf..171Y
No abstract at ADS
Title: A Possible Explanation for the Different Mean Speeds of Halo
and Limb CMEs
Authors: Cheng, J. X.; Yeh, C. T.; Ding, D. M.; Chen, P. F.
Bibcode: 2005IAUS..226..112C
Altcode:
In order to explain the different average speeds between halo and limb
CMEs, we investigate the relationship between the brightness and speed
for 17 halo CMEs. It is found that faster CMEs tend to be brighter,
which implies that many halo CMEs with slow speeds are missed in
observation owing to the limited sensitivity of LASCO detectors or
identifications. As a result, the statistical average speed of halo
CMEs turns to be much larger than that of limb CMEs.
Title: Spectroscopic Detection of Magnetic Reconnection Evidence in
the Solar Atmosphere with SolarB/EIS
Authors: Brooks, D. H.; Isobe, H.; Shibata, K.; Chen, P. F.; Lanzafame,
A. C.
Bibcode: 2004ASPC..325..367B
Altcode:
2.5D MHD simulations of CMEs and flares are combined with improved
accuracy density sensitive line emission contribution functions from
the ADAS database to study profiles of spectral lines which will fall
within the wavelength range of the SolarB Extreme ultraviolet Imaging
Spectrometer (EIS). The objective is to study the signatures of magnetic
reconnection associated flow phenomena in the line profiles and provide
a set of recommended lines for EIS observations planning. Here, we
illustrate our methods by considering the profile of the well-known
Ion{Fe{XII}} 195 AA line and its ability to detect reconnection
inflows. We also discuss the effects of altering simulation parameters
such as electron temperature and the inclusion of the effect of heat
conduction. The table of recommended lines following these methods is
being prepared and will be presented in a separate paper.
Title: Simulated XRT and EIS Observations of Magnetic Reconnection
in Coronal Mass Ejection and X-Ray Arcade
Authors: Shiota, D.; Isobe, H.; Brooks, D. H.; Shibata, K.; Chen, P. F.
Bibcode: 2004ASPC..325..373S
Altcode:
We perform a numerical simulation of a coronal mass ejection and an
associated X-ray arcade. Based on the numerical results, we synthesize
theoretical images taken with XRT and EIS aboard SolarB, and discuss
how reconnection inflow and slow shocks would be observed with XRT
and EIS. The mechanism of dimming is also discussed.
Title: Optically Scaled Ground Demonstration for an External Occulter
Authors: Jordan, I. J. E.; Henze, P.; Sauter, G.; Hart, H. M.; Chen,
P.; Eney, B.; Schultz, A. B.; Bender, E.; Kochte, M.; Lyon, R. G.;
Fraquelli, D.; Bruhweiler, F.; Roelle, C.; Smith, R.; Slepian,
I.; Computer Sciences Corporation; Goddard Space Flight Center;
Westminster Astronomical Society, Inc.; InstituteAstrophysics;
Computational Sciences
Bibcode: 2004AAS...205.3304J
Altcode: 2004BAAS...36.1400J
Results of an optical ground test for an external occulter are
presented. External occulter spacecraft designed to be flown with
a large space based telescope have been proposed as a technique
to enable direct study of exosolar planets. Space-based external
occulters have been used for solar coronal studies, where the occulter
is positioned tens of meters from the telescope, but for exosolar planet
studies the occulter must be positioned thousands of kilometers from
the telescope. While the exoplanet design has been modeled, it has
never, to our knowledge, been field tested. The occulter field
test design is an optically scaled model of a workable space-based
configuration. The telescope aperture diameter, occulting screen
diameter, and telescope-occulter separation were chosen to achieve
the same system Fresnel number as a space-based configuration. The
final ground test configuration consists of a square opaque occulter
screen 25-50 mm on a side, enclosed in a large tube to control stray
light and positioned about 100 meters from a small telescope with
a 9-25 mm aperture mask. Polaris was the test target star, and a
tenth-wave 9-inch circular flat was used to redirect star light to the
telescope. The occulter screen could be removed from the light path
for initial alignment and calibration, then replaced for occultation
tests. Images were taken with a low-noise CCD camera. Preliminary
analysis of the August 2004 data suggests that the occulter performed
as expected with regard to starlight suppression, and suggests that
the occulted PSF could be used by a space-based system to perform
real-time alignment sensing between spacecraft at ranges of tens of
thousands of kilometers. The optical scaling arguments and analysis
of the test images will be presented, along with a discussion of the
alignment procedure and photos of the test rig. We would like
to thank CSC, AURA, GSFC, and WASI for research and equipment support
surrounding this field demonstration.
Title: A Reexamination of the Evidence for Reconnection Inflow
Authors: Chen, P. F.; Shibata, K.; Brooks, D. H.; Isobe, H.
Bibcode: 2004ApJ...602L..61C
Altcode:
In the flare event of 1999 March 18, a threadlike structure observed
in EUV Imaging Telescope images was found to move inward and collapse
to an X-shaped configuration below the ejecta, strongly suggestive
of the occurrence of magnetic reconnection. On the basis of the
numerical results of a coronal mass ejection (CME) flare model, a
similar threadlike structure in the Fe XII 195 Å image is reproduced
in this Letter. It is found that, as in the observations, the thread
experiences an outward motion in the preflare phase, which is followed
by an inward motion. Our simulation suggests that its formation and
outward motion in the preflare phase result from the CME expansion;
after the onset of the flare, the threadlike structure is always
located on the upstream side of the interface between the reconnection
inflow and outflow. Its apparent inward motion, which is several times
slower than the in situ reconnection inflow, is mainly attributed to
the rising motion of the reconnection X-point.
Title: Why are there stationary EIT wave fronts?
Authors: Chen, P. F.; Fang, C.; Shibata, K.
Bibcode: 2004cosp...35..276C
Altcode: 2004cosp.meet..276C
EIT waves are nearly circularly propagating emission enhancements
followed by expanding dimming regions, which have been found to be
closely related with coronal mass ejections. They are generally believed
to correspond to some kind of wave phenomenon. We have explained the
EIT waves as the propagating structures associated with the gradual
opening of coronal mass ejections. However, occasionally a stationary
front can be observed for several hours, which prompted the doubt
about whether the so-called "EIT waves" are pseudo-phenomena. Through
numerical simulations, this paper illustrates how a propagating EIT
wave stops to form the stationary front when it meets another active
region or a coronal hole.
Title: Two homologous CMEs on 2002 May 22
Authors: Chen, J. X.; Fang, C.; Chen, P. F.
Bibcode: 2004cosp...35..233C
Altcode: 2004cosp.meet..233C
Two coronal mass ejections (CMEs) occurred on 2002 May 22, originating
from the same active region, AR 9948. Multi-wavelength data, including
LASCO, EIT, MDI/SOHO, GOES and Hαimages from National Observatory of
China, have been collected in order to clarify the relation between
the CMEs, the associated flares and filament eruptions, and some other
magnetic activities, which is of great importance to understand the
mechanism of each phenomenon. It is proposed that an emerging flux
may trigger the occurrence of the first CME, which in turn drives
the eruption of the second CME, i.e., the two homologous CMEs are
sympathetic. It is also confirmed that the speeds of CMEs are not
positively correlated with the soft X-ray peak flux of the associated
flares. The timing of these phenomena is also given.
Title: Hα and Hard X-Ray Observations of a Two-Ribbon Flare
Associated with a Filament Eruption
Authors: Ding, M. D.; Chen, Q. R.; Li, J. P.; Chen, P. F.
Bibcode: 2003ApJ...598..683D
Altcode: 2003astro.ph..8085D
We perform a multiwavelength study of a two-ribbon flare on
2002 September 29 and its associated filament eruption, observed
simultaneously in the Hα line by a ground-based imaging spectrograph
and in hard X-rays by RHESSI. The flare ribbons contain several
Hα-bright kernels that show different evolutionary behaviors. In
particular, we find two kernels that may be the footpoints of a
loop. A single hard X-ray source appears to cover these two kernels
and to move across the magnetic neutral line. We explain this as a
result of the merging of two footpoint sources that show gradually
asymmetric emission owing to an asymmetric magnetic topology of
the newly reconnected loops. In one of the Hα kernels, we detect
a continuum enhancement at the visible wavelength. By checking its
spatial and temporal relationship with the hard X-ray emission, we
ascribe it to electron-beam precipitation. In addition, we derive the
line-of-sight velocity of the filament plasma based on the Doppler
shift of the filament-caused absorption in the Hα blue wing. The
filament shows rapid acceleration during the impulsive phase. These
observational features are in principal consistent with the general
scenario of the canonical two-ribbon flare model.
Title: Magnetohydrodynamic Numerical Simulations of Coronal Mass
Ejections and Associated Giant Arcades
Authors: Shiota, D.; Shibata, K.; Isobe, H.; Brooks, D. H.; Chen, P. F.
Bibcode: 2003ICRC....6.3379S
Altcode: 2003ICRC...28.3379S
By extending the Chen-Shibata [1] model of coronal mass ejections
(CMEs), we develop physical model of CMEs and associated giant
arcades just below CMEs in two and half dimension, incorporating heat
conduction. On the basis of the simulation results, the theoretical
soft X-ray images are calculated and compared with observations of
CMEs and giant arcades with Yohkoh/SXT (soft X-ray telescope). Detailed
comparison between simulated X-ray images and observations revealed that
(1) the Y-shaped ejection features, often seen at the bottom of some
CMEs, might corresp ond to slow and fast mode MHD shocks associated with
reconnection [3], (2) the dimming, often observed both sides of arcades,
can be produced at least partly by reconnection inflow, (3) the back
bone like bright soft X-ray features seen at the top of some arcades
might corresp ond to fast mode MHD shocks just below reconnection jet.
Title: Slow and Fast MHD Shocks Associated with a Giant Cusp-Shaped
Arcade on 1992 January 24
Authors: Shiota, Daikou; Yamamoto, Tetsuya T.; Sakajiri, Takuma;
Isobe, Hiroaki; Chen, Peng-Fei; Shibata, Kazunari
Bibcode: 2003PASJ...55L..35S
Altcode:
We performed magnetohydrodynamic (MHD) simulations of a giant arcade
formation with a model of magnetic reconnection coupled with heat
conduction, to investigate the dynamical structure of slow and fast MHD
shocks associated with reconnection. Based on the numerical results,
theoretical soft X-ray images were calculated and compared with the
Yohkoh soft X-ray observations of a giant arcade on 1992 January 24. The
Y-shaped structure observed in the event was identified to correspond
to the slow and fast shocks associated with the magnetic reconnection.
Title: Magnetic Reconnection in the Solar Lower Atmosphere
Authors: Fang, C.; Chen, P. F.; Ding, M. D.
Bibcode: 2003ASPC..289..425F
Altcode: 2003aprm.conf..425F
Accumulating observational evidence indicates that magnetic reconnection
is a fundamental process in the solar lower atmosphere, which is
responsible for many localized activities and the global maintenance
of the hot dynamical corona. Meanwhile, qualitative theoretical
considerations and quantitative numerical simulations demonstrate
the applicability of the reconnection to a thin layer in the lower
atmosphere. This paper reviews the research progress in the related
observations, theories and numerical simulations.
Title: Ultrahigh-Energy Plasma Wakefield Acceleration
Authors: Takahashi, Y.; Chen, P.; Tajima, T.
Bibcode: 2003ehcr.conf...93T
Altcode:
No abstract at ADS
Title: Evidence of EIT and Moreton Waves in Numerical Simulations
Authors: Chen, P. F.; Wu, S. T.; Shibata, K.; Fang, C.
Bibcode: 2002ApJ...572L..99C
Altcode:
Solar coronal mass ejections (CMEs) are associated with many dynamical
phenomena, among which EIT waves have always been a puzzle. In this
Letter MHD processes of CME-induced wave phenomena are numerically
simulated. It is shown that as the flux rope rises, a piston-driven
shock is formed along the envelope of the expanding CME, which sweeps
the solar surface as it propagates. We propose that the legs of the
shock produce Moreton waves. Simultaneously, a slower moving wavelike
structure, with an enhanced plasma region ahead, is discerned, which
we propose corresponds to the observed EIT waves. The mechanism for
EIT waves is therefore suggested, and their relation with Moreton
waves and radio bursts is discussed.
Title: The Temperature and Density Structure of an Hα Flaring Loop
Authors: Ding, M. D.; Liu, Y.; Chen, P. F.
Bibcode: 2002SoPh..207..125D
Altcode:
We develop a simple method to deduce the temperature and density in
the loop of a limb flare from the spectral observations of two lines,
Hα and Ca ii 8542 Å. We first build a grid of homogeneous slab models
with various temperature and density values and compute the emergent
line intensities, and then find the relevant model that can match the
observed intensities. This is an approximate method because there are
several other factors which can influence the line intensities. We
apply this method to the limb flare of 11 November 1998 and deduce the
values of temperature and hydrogen number density at different spatial
points in the flaring loop, as well as their temporal variations. The
loop contains relatively high density and possibly the loop top is
slightly hotter and more condensed than the legs of the loop at the
flare maximum time. A favorable scenario to produce this result is
that magnetic reconnection occurs above the loop, and the reconnection
outflow may heat and condense the plasma near the loop top.
Title: Non-LTE Inversion of an Hα Flaring Loop
Authors: Ding, M. D.; Liu, Y.; Chen, P. F.; Fang, C.
Bibcode: 2002stma.conf...89D
Altcode:
No abstract at ADS
Title: A Further Consideration of the Mechanism for EIT Waves
Authors: Chen, P. F.; Shibata, K.
Bibcode: 2002aprm.conf..421C
Altcode:
EIT waves are observed as blurry fronts spreading almost circularly with
enhanced coronal emission. It is found that they are reliable indicators
of the onset of coronal mass ejections, whereas their mechanism has been
a great puzzle. They are often considered as fast mode waves, though
their velocities are much smaller than the Alfven speed. To reconcile
the discrepancy, we proposed in a previous paper that EIT waves are not
real waves, but that they are formed by successive opening of closed
field lines, and the opening is transferred by wave groups. This model
indicates that EIT waves propagate three times slower than Moreton
waves, consistent with observational results. Based on this model, this
paper further illustrates that the EIT wave fronts are blurry in nature,
and their width is comparable with their distance from the flaring site.
Title: A numerical study of flaring loop dynamics during magnetic
reconnection
Authors: Fang, C.; Chen, P. F.; Tang, Y. H.; Di, X. H.
Bibcode: 2002AdSpR..29.1445F
Altcode:
2.5-dimensional magnetic reconnection is numerically simulated for
two cases, one with a high altitude of the reconnection point, the
other with a low altitude. In the former case, bright loops appear to
rise for a long time, with footpoints separating and the field lines
below the bright loops shrinking. In the latter case, the bright loops
cease to rise after a short period of reconnection and become rather
stable. The results imply that the two types of solar flares, i.e.,
two-ribbon flares and compact flares, might be unified under a single
magnetic reconnection model, where the height of the reconnection
point leads to the bifurcation.
Title: ISO and IRAM observations of circumstellar envelopes around
carbon stars with OH maser emission.
Authors: Szczerba, R.; Szymczak, M.; Chen, P.; Omont, A.
Bibcode: 2002cosp...34E.256S
Altcode: 2002cosp.meetE.256S
N. Copernicus Astronomical Center, Torun, Poland Torun Centre for
Astronomy, Torun, Poland 3 Yunnan Astronomical Observatory, Kunming,
China 4 Institut d'Astrophysique, Paris, FranceThe Infrared Space
Observatory (ISO) results concerning late stages of stellar evolution
revealed that coexistence of O-rich and C-rich material is much more
common than previously believed. One class of sources with mixed
chemistry (carbon stars with OH maser emission) was known before
ISO but since OH maser emission is not well spatially resolved this
group did not attract significant attention. However, ISO showed that
at least one subgroup (planetary nebulae with [WR] central stars)
among this class has really mixed chemistry. There is still ongoing
discussion on the origin of such type of mixed chemistry with an
emphasis put on the scenario which involves a kind of reservoir of
oxygen-rich material around some carbon stars. Here, I will report
on our efforts to investigate chemical composition of circumstellar
envelopes around carbon stars with OH maser emission using the ISO
and the IRAM (Institute for Radio Astronomy in the Millimeter Range)
telescopes. The high reflector and pointing accuracy of the IRAM
allows observations of C-based and O-based molecular transitions in
the millimeter range which subsequently can be used to investigate
the chemical contents of the observed circumstellar envelopes.
Title: Coronal mass ejections and emerging flux
Authors: Chen, P. F.; Fang, C.; Shibata, K.; Tang, Y. H.
Bibcode: 2002AdSpR..30..535C
Altcode:
This paper reviews our recent progress in the numerical study of
coronal mass ejections (CMEs) based on flux rope model, which shows
that when the reconnection-favored emerging flux appears either within
or on the outer edge of the filament channel, the flux rope would lose
its equilibrium, and be ejected, while a current sheet is formed below
the flux rope. For the case with emergence within the filament channel,
even small flux is enough to trigger the loss of equilibrium, however,
there is a threshold for the emerging flux on the outer edge of the
filament channel. Given that anomalous resistivity sets in (e.g. when
the current density exceeds a critical value), fast reconnection is
resulted in, leading to fast eruption of the flux rope and localized
flare (either impulsive-type or LDE-type depending on the height of
the reconnection point) near the solar surface. The numerical results
can well explain why CMEs are not centered on flares and provide hints
for CME-flare spatial and temporal relationships.
Title: Mechanism of coronal mass ejections triggered by emerging flux
Authors: Chen, P. F.; Fang, C.; Shibata, K.
Bibcode: 2002HiA....12..394C
Altcode:
No abstract at ADS
Title: Waiting Time Distribution of Coronal Mass Ejections
Authors: Yeh, C. -T.; Ding, M. D.; Chen, P. F.
Bibcode: 2002aprm.conf..471Y
Altcode:
Coronal mass ejections (CME) and flares are believed to be the result of
rapid release of magnetic energy. The energy release process in solar
flares can be interpreted as avalanches of many small reconnection
events, that is, the statistical properties of the flaring events can
be described in a simple sandpile model. In this paper, we use the
avalanche model to investigate the frequency distribution of coronal
mass ejections, and we find the frequency distribution of coronal mass
ejections is similar to that of flares.
Title: On the directions of solar filament eruptions
Authors: Morimoto, T.; Asai, A.; Isobe, H.; Chen, P.; Kurokawa, H.
Bibcode: 2002cosp...34E1178M
Altcode: 2002cosp.meetE1178M
We report on the relation between directions of solar filament
eruptions and the distribution of magnetic field strengths at and
near the source regions. The solar filaments and prominences become
cores of coronal mass ejections (CMEs) when they are ejected into the
interplanetary space. These CMEs appear as halo CMEs when directed
toward the earth, and they often cause geomagnetic storms. It is,
therefore, very important to know the direction of a CME before or
in the initial phase of its onset. Making use of H line center, blue
and red wing images, together with the Doppler method, we measured 3D
velocity field of more than 15 events of solar disappearing filament
(SDF). From the velocity field, we obtained the directions of these
SDFs, and compared it with the distributions of photospheric magnetic
field strengths. We found that both orientation angle (angle by the
solar meridian and a vector of the direction of a filament projected
onto the solar surface) and ejection angle (elevationangle measured
against the solar surface) well match with the vector of local gradient
of photospheric magnetic field strengths. The possibility to predict
the direction of a CME even before its onset is also discussed.
Title: Magnetic Reconnection in the Solar Lower Atmosphere
Authors: Fang, C.; Chen, P. F.; Ding, M. D.
Bibcode: 2002stma.conf....3F
Altcode:
No abstract at ADS
Title: Prompt Signals of Gamma Ray Bursts
Authors: Chen, P.
Bibcode: 2001STIN...0217696C
Altcode:
We introduce a new model of gamma ray burst (GRB) that explains its
observed prompt signals, namely, its primary thermal spectrum and high
energy tail. This mechanism can be applied to either assumption of
GRB progenitor: coalescence of compact objects or hypernova explosion.
Title: Global destabilization due to localized reconnection: A
mechanism for coronal mass ejections
Authors: Chen, P. F.; Shibata, K.; Yokoyama, T.
Bibcode: 2001EP&S...53..611C
Altcode:
Solar CMEs are large scale eruptive phenomena, while flux emergence
is a local event on the Sun. Our numerical simulations show that
two categories of reconnection-favored emerging flux can trigger
the destabilization and the ejection of the filament (i.e., CME):
within the filament channel or on the outer edge of the channel, which
confirms recent important observations by Feynman and Martin (1995). In
particular for the latter category, numerical results show that there
is a critical amount for the emerging flux, below which the flux rope
eruption cannot be triggered. Our numerical model, for the first time,
provides a physical explanation for the observed correlation between
CMEs and the reconnection-favored emerging flux.
Title: Generalized Uncertainty Principle and Black Hole Remnants
Authors: Chen, P.
Bibcode: 2001STIN...0211724C
Altcode:
In the current standard viewpoint small black holes are believed
to emit black body radiation at the Hawking temperature, at least
until they approach Plan size, after which their fate is open to
conjecture. A cogent argument against the existence of remnants
is that, since no evident quantum number prevents it, black holes
should radiate completely away to photons and other ordinary stable
particles and vacuum, like any unstable quantum system. Here we argue
the contrary, that the generalized uncertainty principle may prevent
their total evaporation in exactly the same way that the uncertainty
principle prevents the hydrogen atom from total collapse: the collapse
is prevented, not by symmetry, but by dynamics, as a minimum size and
mass are approached.
Title: Ellerman Bombs, Type II White-light Flares and Magnetic
Reconnection in the Solar Lower Atmosphere
Authors: Chen, Peng-Fei; Fang, Cheng; Ding, Ming-De Ding
Bibcode: 2001ChJAA...1..176C
Altcode:
Ellerman bombs and Type II white-light flares share many common features
despite the large energy gap between them. Both are considered to
result from local heating in the solar lower atmosphere. We present
numerical simulations of magnetic reconnection occurring in such a deep
atmosphere, with the aim to account for the common features of the two
phenomena. Our numerical results manifest the following two typical
characteristics of the assumed reconnection process: (1) magnetic
reconnection saturates in ~600-900 s, which is just the lifetime of
the two phenomena; (2) ionization in the upper chromosphere consumes
quite a large part of the energy released through reconnection, making
the heating effect most significant in the lower chromosphere. The
application of the reconnection model to the two phenomena is discussed
in detail.
Title: Resonant Photon-Graviton Conversion as a Probe into
Inflationary Universe
Authors: Chen, P.
Bibcode: 2001sddm.symp..149C
Altcode:
No abstract at ADS
Title: A Photonic Local Oscillator Source for Far-IR and Sub-mm
Heterodyne Receivers
Authors: Matsuura, S.; Blake, G. A.; Chen, P.; Wyss, R. A.; Pearson,
J. C.; Pickett, H. M.; Jackson, A. W.; Kadow, C.; Gossard, A. C.
Bibcode: 2000ISASS..14..337M
Altcode:
We presented a recently developed compact solid-state far-infrared and
sub-mm (terahertz) source. The radiation is generated by the optical
heterodyne conversion (photomixing) in a low-temperature-grown GaAs
(LTG-GaAs) photoconductor with a sub-picosecond response time. In
photomixing, two frequency-offset laser beams are used to illuminate
the photoconductor, resulting in the photocurrent oscillation at the
difference frequency that drives a planar antenna on the device. Such
a photonic source has the great advantage of compactness, wide tuning
range and high efficiency over existing electronic devices, and would
be suitable for use as local oscillators in heterodyne receivers for
IR/sub-mm astronomy.
Title: An Emerging Flux Trigger Mechanism for Coronal Mass Ejections
Authors: Chen, P. F.; Shibata, K.
Bibcode: 2000ApJ...545..524C
Altcode:
Observations indicate that reconnection-favored emerging flux has
a strong correlation with coronal mass ejectons (CMEs). Motivated
by this observed correlation and based on the flux rope model, an
emerging flux trigger mechanism is proposed for the onset of CMEs,
using two-dimensional magnetohydrodynamic (MHD) numerical simulations:
when such emerging flux emerges within the filament channel, it cancels
the magnetic field below the flux rope, leading to the rise of the flux
rope (owing to loss of equilibrium) and the formation of a current sheet
below it. Similar global restructuring and a resulting rise motion
of the flux rope occur also when reconnection-favored emerging flux
appears on the outer edge of the filament channel. In either case, fast
magnetic reconnection in the current sheet below the flux rope induces
fast ejection of the flux rope (i.e., CME). It is also shown that the
nonreconnecting emerging flux, either within the filament channel or
on the outer edge of the channel, makes the flux rope move down, i.e.,
no CMEs can be triggered. Although the present two-dimensional model
can not provide many details of the largely unknown three-dimensional
processes associated with prominence eruptions, it shows some
observational features such as the height-time profile of erupting
prominences. Most importantly, our model can well explain the observed
correlation between CMEs and the reconnection-favored emerging flux.
Title: Testing Event Horizon with Violent Acceleration Using Intense
Lasers*
Authors: Chen, P.
Bibcode: 2000AAS...196.2210C
Altcode: 2000BAAS...32R.705C
The well-known Hawking radiation from the black holes relies on
the existence of the event horizon. The detailed understanding of
the nature of the event horizon is of fundamental importance in
physics. It has been demonstrated that a similar radiation effect
(by the name "acceleration radiation", or "Unruh radiation") should
occur for a "particle detector" under uniform acceleration, where
there also exists an event horizon viewed from the proper frame of the
particle. As the nature of the event horizon is generic to both cases,
it is proposed that the physics associated with the black hole event
horizon can be simulated and studied in the laboratory setting via
violent acceleration induced by intense lasers. The Unruh radiation
power from an electron is derived and its angular-frequency spectrum
characterized. We then compare these to the competing classical Larmor
radiation background. An experiment is proposed, where, under reasonable
assumption of laser parameters, the signal-to-noise ratio is shown to
be favorable for the detection of the Unruh radiation. * Work supported
by the U.S. Department of Energy under contract No. DE-AC03-76SF00515.
Title: Numerical Study on the Effect of Heat Conduction on Magnetic
Reconnection
Authors: Chen, P. F.; Fang, C.; Tang, Y. H.; Ding, M. D.
Bibcode: 2000AdSpR..26..525C
Altcode:
The effect of heat conduction on 2.5D magnetic reconnection, similar
to that in Kopp-Pneuman model, is numerically studied. It is shown
that the heat conduction accelerates the reconnection, increases
the amount of shrinkage of the closed field lines, and increases the
average rise speed of the SXR loop. MHD slow shocks contribute to the
SXR loop heating. When the timescale of heat conduction is shorter
than the Alfvén timescale, an adiabatic slow shock is dissociated
into an isothermal slow shock and a heat conduction front
Title: A Photonic Local Oscillator Source for Far-IR and Sub-mm
Heterodyne Receivers
Authors: Matsuura, S.; Blake, G. A.; Chen, P.; Wyss, R. A.; Pearson,
J. C.; Pickett, H. M.; Jackson, A. W.; Kadow, C.; Gossard, A. C.
Bibcode: 2000mfia.conf..337M
Altcode:
A recently developed compact solid-state far-infrared and sub-mm
(terahertz) source is presented. The radiation is generated by the
optical heterodyne conversion (photomixing) in a Low-Temperature-Grown
GaAs (LTG-GaAs) photoconductor with a sub-picosecond response time. In
photomixing, two frequency-offset laser beams are used to illuminate
the photoconductor, resulting in the photocurrent oscillation at the
difference frequency that drives a planar antenna on the device. Such
a photonic source has the great advantage of compactness, wide tuning
range and high efficiency over existing electronic devices, and would
be suitable for use as local oscillators in heterodyne receivers for
IR/sub-mm astronomy.
Title: Evolution of Magnetic Field and CMEs
Authors: Fang, C.; Chen, P. F.; Tang, Y. H.; Shibata, K.
Bibcode: 2000IAUJD...7E..17F
Altcode:
Observations show that some evolving magnetic structures occur in
solar active regions before the onset of CMEs. In 2D framework, through
changing the bottom boundary of magnetic field, we simulate numerically
the dynamics of the coronal plasma with a magnetic configuration similar
to a filament. In some cases, we find the flux rope (or filament) loses
its equilibrium, and moves upward. A current sheet is formed below the
filament. If there is no reconnection or the reconnection is not so
fast, the filament will finally stop motion and fall down, while when
fast reconnection occurs, the filament erupts. The characteristics of
its motion are well consistent with filament eruptions and CMEs. After
the reconnection, a cusp shaped hot X-ray loop is formed as the
signature of solar flares. This model provides deep insight on the
relation between the photospheric magnetic field variation and the
onset of CMEs, and on the relation between CMEs and solar flares.
Title: Comment on "EM induction in elongated conductors normal to a
coastline with application to geomagnetic measurements in Nigeria"
by J. Chen, H. W. Dosso and S. Kang
Authors: Chen, P. F.
Bibcode: 1999EP&S...51..997C
Altcode:
No abstract at ADS
Title: Multi-line two-dimensional spectroscopy of a limb flare
Authors: Ding, M. D.; Fang, C.; Yin, S. Y.; Chen, P. F.
Bibcode: 1999A&A...348L..29D
Altcode:
We present the result of a preliminary analysis of the 2D spectra of Hα
and Ca ii lambda 8542 for a limb flare on 11 November, 1998. Near the
top of the flaring loop, the Hα line is extraordinarily broadened. The
effect of line opacity (or the saturation of line core) cannot fully
account for the observed line width since it requires an extremely high
loop density (n_H>~ 10(13) cm(-3) when T=10(4) K). The remaining
possibility is the broadening by micro-turbulence or inhomogeneous mass
motions. Since the two lines demonstrate different broadening effects,
it is quite possible that they are formed in different fine structures
which cannot be spatially resolved by observations.
Title: Fluid Inclusion Evidence for High-Copper Content of Ore-Forming
Fluid for Xifanping Porphyry Copper Deposit, Sichuan Province, China
Authors: Chen, P.; Wang, R.; Chen, X.; Xu, S.
Bibcode: 1999nag..conf.7285C
Altcode:
No abstract at ADS
Title: Flaring Loop Motion and a Unified Model for Solar Flares
Authors: Chen, P. F.; Fang, C.; Ding, M. D.; Tang, Y. H.
Bibcode: 1999ApJ...520..853C
Altcode:
We performed 2.5-dimensional numerical simulations of magnetic
reconnection for several models, some with the reconnection point at a
high altitude (the X-type point in magnetic reconnection), and one with
the reconnection point at a low altitude. In the high-altitude cases,
the bright loop appears to rise for a long time, with its two footpoints
separating and the field lines below the bright loop shrinking, which
are all typical features of two-ribbon flares. The rise speed of the
loop and the separation speed of its footpoints depend strongly on
the magnetic field B0, to a medium extent on the density
ρ0, and weakly on the temperature T0, the
resistivity η, and the length scale L0, by which the size
of current sheet and the height of the X-point are both scaled. The
strong B0 dependence means that the Lorentz force is the
dominant factor; the inertia of the plasma may account for the moderate
ρ0 dependence; and the weak η dependence may imply that
``fast reconnection'' occurs; the weak L0 dependence implies
that the flaring loop motion has geometrical self-similarity. In the
low-altitude case, the bright loops cease rising only a short time
after the impulsive phase of the reconnection and then become rather
stable, which shows a distinct similarity to the compact flares. The
results imply that the two types of solar flares, i.e., the two-ribbon
flares and the compact ones, might be unified into the same magnetic
reconnection model, where the height of the reconnection point leads
to the bifurcation.
Title: The Balloon-Launched Asteroseismology Telescope (BLAST)
Authors: Murphy, G.; Buzasi, D.; Brown, T.; Chen, P.
Bibcode: 1999AAS...194.0818M
Altcode: 1999BAAS...31..836M
Asteroseismology, the study of stellar oscillations, provides the
only way to directly probe the internal structure and rotation of
stars. The simplest way to measure oscillations is through searches for
periodic micromagnitude-level variations in the stellar luminosity;
such searches are prohibitive from the ground (requiring hundreds of
nights of time on several 4-meter class telescopes) due to atmospheric
scintillation and the inability to obtain long uninterrupted observing
periods without encountering the extremely hostile nighttime polar
environment. Although all of the difficulties encountered by terrestrial
attempts at asteroseismology are obviated by observing from space,
such platforms introduce added complexity and cost. However, most
of the advantages of space can be achieved by flying a 0.25 to 0.5
meter telescope feeding a white-light CCD photometer on a balloon at
altitudes in excess of 30 km, and the upcoming generation of ultra
long duration balloons, make this option even more attractive. We
describe the Balloon-Launched Asteroseismology Telescope (BLAST),
a proposed University-class Explorer mission, which is designed to
perform asteroseismology on solar-like visual binary systems.
Title: Simulation of Magnetic Reconnection with Heat Conduction
Authors: Chen, P. F.; Fang, C.; Tang, Y. H.; Ding, M. D.
Bibcode: 1999ApJ...513..516C
Altcode:
Magnetohydrodynamic (MHD) equations are numerically solved to study
2.5-dimensional magnetic reconnection with field-aligned heat
conduction, which is also compared with the adiabatic case. The
dynamical evolution starts after anomalous resistivity is introduced
into a hydrostatic solar atmosphere with a force-free current sheet,
which might be similar to the configuration before some solar
flares. The results show that two jets (i.e., the outflows of the
reconnection region) appear. The downward jet collides with the closed
line-tied field lines, and a bright loop is formed with a termination
shock at the loop top. As the reconnection goes on, the loop rises
almost uniformly with a speed of tens of km s-1, and the two
footpoints of the loop separate with a speed comparable to the loop rise
speed. Besides the apparent loop motion, the magnetic loops below the
loop top shrink weakly. Such a picture is consistent with that given by
observations of two-ribbon solar flares. Moreover, the results indicate
that the slow MHD shock contributes to the bright loop heating. Some
detailed structures of the reconnection process are also discussed.
Title: Magnetic Reconnection and Flare Loop Motion
Authors: Chen, P. F.; Fang, C.; Tang, Y. H.; Ding, M. D.
Bibcode: 1999ASSL..240..337C
Altcode: 1999numa.conf..337C
No abstract at ADS
Title: Telescope mirrors successfully lose weight.
Authors: Chen, P.
Bibcode: 1998LaFW...34...69C
Altcode:
A new generation of extremely lightweight Earth-, space-, or Moon-based
telescopes may be possible with a composite-mirror technology. The
optical replication technique has produced 0.6-m-diameter thin-facesheet
mirrors weighing less than 1 kg, 0.9-m core-reinforced mirrors
weighing 4 kg, and a 1.5×2.5-m reflector array approaching 23 kg. The
replication of the mirrors with graphite fiber-reinforced composites
keeps them thin.
Title: Step-scan FTIR absorption difference time-resolved spectroscopy
studies the excited state electronic structures and decay kinetics
of d6 transition metal polypyridine complexes
Authors: Smith, G. D.; Paegel, B. M.; Palmer, R. A.; Chen, P.; Omberg,
K. M.; Meyer, T. J.
Bibcode: 1998AIPC..430..708S
Altcode: 1998fts..conf..708S
Step-scan FTIR absorption difference time-resolved spectroscopy
(S2 FTIR ΔA TRS) has been used to study the photo-excited
states of several low-spin d6 transition metal polypyridine
complexes. Insight into the distribution of electron density in the
excited states is obtained by comparing the ground and excited state
vibrational frequencies of various bands sensitive to electronic
structure. The multiplex, registration, and IR throughput advantages
of this interferometric technique are significant in comparison with
other methods currently used to probe photo-excited processes on
the nanosecond time scale. The S2 FTIR ΔA TR spectra were
obtained by use of a step-scan modified Bruker IFS 88 FTIR spectrometer
equipped with an AC/DC-coupled photovoltaic Kolmar Technologies MCT
detector with a 20 ns rise time and a 100/200 MHz PAD82a transient
digitizer. The complexes were excited with frequency-tripled pulses
from a Q-switched Quanta-Ray DCR1A Nd:YAG laser (355 nm, 10 ns, 10 Hz,
3 mJ/pulse). Data were collected with 10 ns time resolution.
Title: A High-Power Frequency-Stabilized Tunable Two-Frequency Diode
Laser System for Generation of Coherent Terahertz-Wave by Photomixing
Authors: Matsuura, S.; Blake, G.; Chen, P.; Pearson, J. C.; Pickett,
H. M.
Bibcode: 1998stt..conf..445M
Altcode:
No abstract at ADS
Title: Delineation of rice cropping systems in the Mekong delta
river using multitemporal ERS-SAR
Authors: Liew, S. C.; Kam, S. P.; Tuong, T. P.; Chen, P.; Minh, V. Q.;
Balababa, L.; Lim, H.
Bibcode: 1997ESASP.414..153L
Altcode: 1997sse..symp..153L
No abstract at ADS
Title: Infrared study of the H II region - molecular cloud complex
S141.
Authors: Li, J.; Chen, P.
Bibcode: 1996PYunO..62...39L
Altcode:
No abstract at ADS
Title: Infrared study of the H II region - molecular cloud complex
S140.
Authors: Li, J.; Chen, P.
Bibcode: 1996PYunO..62...29L
Altcode:
No abstract at ADS
Title: LXeCAT: A Balloon Borne Liquid Xenon Imaging Telescope for
MeV Gamma-Ray Astronomy
Authors: Aprile, E.; Xu, F.; Zhou, M.; Chen, P.; Ishida, N.; Doke,
T.; Kiluchi, J.; Masuda, K.; Chupp, E. L.; Dunphy, P. P.; Fishman,
G.; Pendleton, G.
Bibcode: 1995AAS...18712101A
Altcode: 1995BAAS...27.1452A
LXeCAT is a balloon borne experiment which will be capable of imaging
gamma -ray astrophysical sources in the energy region from 300 keV to
10 MeV, with a point source location accuracy of few arcminutes. The
telescope consists of a Liquid Xenon Time Projection Chamber (LXe-TPC)
as three-dimensional position sensitive detector, coupled to a coded
aperture mask. A 10 liter LXe-TPC prototype with an active area of 20
cm x 20 cm has been constructed to evaluate the design and engineering
aspects of this type of detector for space applications and to test
and calibrate its response for spectroscopy and imaging of gamma -rays
at MeV energies. In this paper we review the properties of LXeCAT and
present results from laboratory tests of the prototype.
Title: Gravitational field of a global cosmic string with non-linear
Lagrangian.
Authors: Jiang, Yuanfang; Chen, Peng
Bibcode: 1995NCimB.110.1391J
Altcode:
In this paper the metric outside a straight global string is derived,
with the high-derivative gravitational theory which has a higher
correction as compared with Einstein gravitational theory. The effect
of accreting matter and the formation of the large-scale structure of
the Universe may be very important.
Title: The absolute K magnitude and the distance of OH/IR stars.
Authors: Xiong, G.; Chen, P.
Bibcode: 1995PYunO..60....1X
Altcode:
No abstract at ADS
Title: Infrared study of the HII region - molecular cloud complex
S 142.
Authors: Li, J. Z.; Chen, P.
Bibcode: 1995PYunO..61...30L
Altcode:
No abstract at ADS
Title: Equatorial Ionospheric F-Region Irregularities and its
Characteristics at East Asia Sector - a Review
Authors: Wang, W.; Chen, P.
Bibcode: 1990PYunO..75....1W
Altcode:
No abstract at ADS
Title: Nonlocal Analysis of Gradient Drift Instability in the Daytime
Equatorial Electrojet
Authors: Chen, P.
Bibcode: 1990PYunO..36....1C
Altcode:
No abstract at ADS
Title: Studies of Dynamic Processes of Sporadic-E Layers with
Digital Ionosphere
Authors: Cai, H.; Chen, P.
Bibcode: 1990PYunO.164....1C
Altcode:
No abstract at ADS
Title: Two-Day Oscillation of the Equatorial Anomaly
Authors: Chen, P.
Bibcode: 1990PYunO...7....1C
Altcode:
No abstract at ADS
Title: On the behaviour of the imaginary Parkinson arrows near the
anomalous conductor-host medium interface
Authors: Chen, P. F.; Fung, P. C. W.
Bibcode: 1988PEPI...50..195C
Altcode:
A set of numerical modelling is carried out for studying the behaviour
of the Parkinson arrows near the anomalous conductor-host medium
interface. In these models the conductivity contrast between the
conducting plate and the host medium is taken to be 5700. Our results
indicate that the imaginary Parkinson arrow and the real Parkinson
arrow do not change their signs directly over the plate-host interface.
Title: Acceleration of electrons by the interaction of a bunched
electron beam with a plasma
Authors: Chen, P.; Dawson, J. M.; Huff, R. W.; Katsouleas, T.
Bibcode: 1985PhRvL..54..693C
Altcode:
A scheme for accelerating electrons is proposed which uses a bunched
relativistic electron beam in a cold plasma. Lasers are not required,
and large energy gradients (exceeding 1 GeV/m) are attained. As in
the two-stream instability, the streaming relativistic electrons lose
energy to the background plasma by exciting a wake plasma wave. If
a late-coming electron bunch rides on the wave at a proper phase,
it will be boosted to a higher energy as a result of the longitudinal
electric field in the wave. A noncollinear injection scheme is proposed
in order that the driving electrons can be removed.
Title: Significance of the sign changing of the imaginary arrows in
geomagnetic induction investigation
Authors: Chen, P. F.; Fung, P. C. W.
Bibcode: 1985GeoJ...80..257C
Altcode: 1985GeoJI..80..257C
No abstract at ADS
Title: The Development and Adjustment of a Blackbody for the Near
Infrared Photometer
Authors: Qi, X.; Chen, P.
Bibcode: 1981PYunO...2...20Q
Altcode:
No abstract at ADS
Title: The Performance Test of the 1-MICRON to 3-MICRON Infrared
Photometer
Authors: Chen, P.; Zhang, Y.; Qi, X.; Kao, H.
Bibcode: 1981PYunO...2...24C
Altcode:
No abstract at ADS
Title: Test Observations of the 1-MICRON to 3-MICRON Infrared
Photometer
Authors: Kao, H.; Chen, P.; Zhang, Y.; Qi, X.
Bibcode: 1981PYunO...2...31K
Altcode:
No abstract at ADS
Title: Automated astroposition determination using sensor array
systems.
Authors: Chen, P. -F.; Allen, W. A.
Bibcode: 1977ITIM...26..197C
Altcode:
A method for determining astronomic position which involves an
optical sensor array instead of the conventional optical micrometer is
tested. The experimental apparatus, which includes a T-4 theodolite,
a 50 by 50-element self-scanning photodiode array and an electronic
signal processor, is described; both laboratory simulations and actual
observations of stars were conducted using the system. The automatic
position determination has the advantage of eliminating human errors,
especially those associated with human reaction times. It is suggested
that modifications in the experimental apparatus could increase
resolution to 0.1 arcsecond and allow for detection of stars as faint
as the sixth or seventh magnitude.
Title: Nova Ophiuchi 1976
Authors: Pesch, P.; Chen, P.; Loucka, L.; Robertson, T.; Stephenson,
C. B.; Sanduleak, N.
Bibcode: 1976IAUC.2996....1P
Altcode:
P. Pesch, Warner and Swasey Observatory, reports that an objective
prism plate taken with the Burrell Schmidt telescope on Oct. 19.0 UT by
P. Chen, L. Loucka and T. Robertson shows the spectrum of the 'novalike
object in Ophiuchus' (IAUC 2994) to be that of a nova approximately 3-4
magnitudes below maximum. According to C. B. Stephenson the following
emission lines appear to be present in the spectrum: H-alpha, H-beta,
N III 4640 A, H-gamma + [O III] 4363 A, He + [Ne III] 3968 A, H-zeta +
[Ne III] 3869 A. The width of H-beta, estimated to be ~50 A, indicates
that the nova is a moderately fast one. N. Sanduleak derived the
magnitude B = 12.5 +/- 0.5 (on Oct. 19.0) and noted no star in this
position on the red Palomar Sky Survey print.
Title: Stephenson 557
Authors: Pesch, P.; Stephenson, C. B.; Sanduleak, N.; Chen, P.
Bibcode: 1976IAUC.2979....1P
Altcode:
P. Pesch, Warner and Swasey Observatory, reports that C. B. Stephenson
and N. Sanduleak have identified the long-period variable (Kuwano's
"possible nova") in Scutum (IAUC 2978) with No. 557 in the General
Catalogue of S Stars (Stephenson 1976, Publ. Warner and Swasey Obs. 2,
21), where its position is given as R.A. = 18h24m07s.9, Decl. =
-14o43'38" (equinox 1950.0). They confirm the star's variability. An
objective-prism plate (dispersion 280 A/mm) obtained with the Burrell
Schmidt telescope on July 22 UT by Stephenson and P. Chen shows the
star near the plate limit at blue magnitude ~ 13; the star is somewhat
reddened and exhibits fairly narrow H-beta and H-gamma emission.
Title: Nova Cygni 1975
Authors: Gieren, W.; Seggewiss, W.; Pesch, P.; Chen, P.; Gilbert,
G. R.; Tempesti, P.; Lukas, R.; Sherrod, C.; Williams, T. R.; Maley, P.
Bibcode: 1975IAUC.2842....1G
Altcode:
W. Gieren and W. Seggewiss, Hoher List Observatory, write that a
spectrogram (dispersion 29 A/mm) obtained on Sept. 4.849 UT shows
that the Balmer lines were split into four emission peaks with four
corresponding violet-displaced absorption edges. This structure
was not present on Sept. 1.875 and earlier. On the other hand, the
four emissions and absorptions were again evident on Sept. 17.090,
with little change in the velocities. The velocities (km/s) were:
1975 UT E1 A1 E2 A2 E3 A3 E4 A4 Sept. 4 H-gamma + 739 + 427 + 210
- 169 - 469 - 762 -1051 -2538 17 H-gamma + 732 + 426 + 196 - 185 -
452 - 816 - 951 -3074 17 H-beta + 675 + 366 + 209 - 131 - 455 - 733 -
936 -3154 where the designations E1-E4 refer to the emission peaks,
A1-A4 to the absorption edges. The velocities could be measured quite
accurately, with the exception of the very broad and shallow absorption
feature A4. It should be especially noted that E1 and E2, as well
as A1, are shifted toward the red part of the spectrum. P. Pesch,
Warner and Swasey Observatory, communicates the following remarks by
P. Chen on image-tube spectrograms taken with the 91-cm telescope on
Sept. 22 UT: "Spectrograms at a dispersion of about 100 A/mm show
that the nova is probably in the late Orion-early nebular stage,
very similar to McLaughlin's synthetic spectrum of a nova about five
magnitudes past maximum. The 4959, 5007 A complex has strengthened
but not separated into distinct components. The N III 4640 A, He
II 4686 A complex is strong and distinct, and H-beta has distinctly
narrowed (present width ~ 50 A or 3000 km/s). The Fe II (multiplet
42) lines are barely discernible. A higher dispersion (~ 24 A/mm)
spectrogram of H-alpha shows four distinct emission components." A
telegram received from G. R. Gilbert et al., University of Arizona,
on Sept. 30 reports: "The Steward Observatory television scanner (and
an image-tube configuration) shows O 8446 A (3p-3s) emission to be of
comparable strength to H-alpha. Fourier-transform spectra by both Lunar
and Planetary Laboratory and Steward Observatory instruments show O
1.1287 um (3d-3p) to be comparable to P-beta and O 1.3164 um (4s-3p)
to be absent. These results show that the oxygen lines are fed by a
fluorescent mechanism from L-beta and that the nova envelope has a
large optical depth in H-alpha." P. Tempesti, Collurania Observatory,
writes that the 3-hour-period variation in brightness (IAUC 2834) was
confirmed by observations on Sept. 11 and 14; on the latter date the
amplitude of the variation had decreased to 0.05 magnitude. Further
recent visual magnitude estimates: Sept. 17.9 UT, 7.7 (R. Lukas,
Wilhelm Foerster Observatory); 19.07, 7.1 (C. Sherrod, North Little
Rock, Arkansas); 21.17, 7.3 (Sherrod); 23.09, 7.5 (T. R. Williams,
Houston, Texas); 25.08, 7.3 (P. Maley, Houston, Texas); 27.06, 7.4
(Maley); 28.04, 7.4 (Maley); 29.05, 7.4 (Maley).
Title: Nova Aquilae 1975
Authors: Pesch, P.; Sanduleak, N.; Chen, P.
Bibcode: 1975IAUC.2835....2P
Altcode: 1975IAUC.2835R...1P
P. Pesch, Warner and Swasey Observatory, reports that an objective-prism
plate taken by him on Sept. 7 UT with the Burrell Schmidt telescope
shows that the spectrum of the object initially described as an eruptive
variable in Aquila (IAUC 2788, 2795, 2802), and then as Nova Aql 1975
(IAUC 2811, 2821), is indeed that of a nova. According to N. Sanduleak
and P. Chen, the nova is now in its early nebular stage. Coverage of
the 4500-6800 A region shows strong H-alpha (somewhat narrower than
observed in most novae) and weak emission features identified as [N II]
5755 A and [O III] 5007 A.
Title: Nova Scuti 1975
Authors: Pesch, P.; Chen, P.; Lukas, R.; Kiehl, M.; Bortle, J.;
Sherrod, C.
Bibcode: 1975IAUC.2840....2P
Altcode:
P. Pesch, Warner and Swasey Observatory, communicates the following
remarks by P. Chen on image-tube spectrograms (dispersion 100 A/mm)
taken with the 91-cm telescope on Sept. 22.08 UT: "The nova is now in
the final nebular stage (~ 5 magnitudes below and after maximum in
McLaughlin's description). The 4959, 5007 A features are strong and
distinct; the profiles are almost square with width ~ 30 A (~ 2000
km/s). H-beta has also narrowed down to a square profile of width ~
2000 km/s. H-gamma + [O III] 4363 A is strong with a total width of
~ 50 A (~ 3000 km/s)." Further selected visual magnitude estimates:
Aug. 29.0, 10.3 (R. Lukas, Wilhelm Foerster Observatory); Sept. 2.81,
10.5 (M. Kiehl, Wilhelm Foerster Observatory); 4.05, 11.2 (J. Bortle,
Brooks Observatory); 7.84, 10.6 (Kiehl); 11.04, 11.2 (Bortle); 13.9,
10.4 (Lukas); 15.05, 11.1 (Bortle); 15.14, 11.4 (C. Sherrod, North
Little Rock, Arkansas); 18.14, 11.4 (Sherrod).
Title: Nova Cygni 1975
Authors: Wright, E.; Racine, R.; Irwin, A.; Fehrenbach, Ch.; Andrillat,
Y.; Strittmatter, P. A.; Bolton, T.; Gulliver, A.; McCrosky, R. E.;
Schwartz, G.; Neff, J. S.; Pesch, P.; Stephenson, C. B.; Chen, P.;
Gallagher, J.; Ney, E. P.; Kleinmann, S. G.; Turner, M.
Bibcode: 1975IAUC.2829....1W
Altcode:
E. Wright, Harvard College Observatory, confirms that the magnitude 16
star on the Palomar Sky Survey prints (cf. IAUC 2826) is 10" from the
nova. R. Racine, David Dunlap Observatory, reports that measurement
of plates taken by A. Irwin shows that the magnitude 19 star is 5".5
away. It is unlikely that the proper motion of either is sufficient to
permit identification with the prenova. Ch. Fehrenbach and Y. Andrillat,
Haute Provence Observatory, report: "Large-dispersion spectrograms
obtained with the 193- and 152-cm reflectors between A3200 and A8750
on Aug. 29.9176 UT show a practically continuous spectrum. Only H-beta
and O I 7772 A are weakly visible as wide absorption features. The
interstellar (Ca II, Na I, 6280 A, etc.) and telluric lines are very
narrow. The spectrum evolved very rapidly, for on Aug. 30.8646 the
following lines appear: H (Balmer and Paschen series), O I (multiplets
1, 4, 34), N I (1, 2), Si II (1, 2), Ca II, Na I, Fe II (27, 37, 38, 42,
74), Ti II (13, 14) and Mg II (4). These lines are visible in absorption
- and also in emission for the most intense. The lines are very wide,
the absorptions giving a velocity of -1700 km/s. The intensity of the
lines had increased on Aug. 31. The nature of the spectrum on Aug. 29
(before maximum) is particularly remarkable." P. A. Strittmatter,
Steward Observatory, reports that on Aug. 30 the spectrum was diffuse,
with very weak P-Cyg profiles at H-alpha, H-beta and H-gamma, He I
4471 and 3888 A, slowly strengthening during the night; there was
broad, weak emission at H and K. On Aug. 31.3 UT there were strong,
broad P-Cyg profiles. Interstellar H, K and D lines appeared with
multiple components. Between 3300 and 9700 A the polarization was
normal Cygnus interstellar with a peak value of 1.2 percent at 5200
A. T. Bolton and A. Gulliver, David Dunlap Observatory, report that
numerous high-dispersion spectrograms, obtained with the 188-cm
telescope between Sept. 1.13 and 1.40 UT show a spectrum similar to
that of an A supergiant with extremely broad (20 to 60 A) absorption
and emission lines. Lines of H, Fe II, Na I, Ca II, Mg II, O I and
possibly Mg I are present. The H lines to at least He and some of the
Fe II lines have P-Cyg profiles. No changes in the spectrum were found
during the observing period. The mean absorption velocity is -1670 +/-
60 km/s; the mean emission velocity is -75 +/- 50 km/s. Some of the
scatter in the velocities appears to be real. The Balmer absorption
velocities vary smoothly from -2100 km/s at H-alpha to -1400 km/s
at H_10. Interstellar lines of Ca II, Na I and CH+ are present at a
velocity of -11 km/s. The equivalent width of the interstellar K line
is 0.37 A. R. E. McCrosky and G. Schwartz, Harvard College Observatory,
report that low-resolution spectrograms show predominantly continuum on
Aug. 31.3 UT, comparable continuum and emission (H, O I, Na I, etc.) on
Sept. 1.1, and practically all emission on Sept. 3.2. J. S. Neff,
Department of Physics and Astronomy, State University of Iowa, reports
that though the continuum was weaker on Sept. 2 UT, and especially on
Sept. 3, H-beta emission was comparable to that on Sept. 1. H-alpha
was becoming more intense. P. Pesch, Warner and Swasey Observatory,
communicates the following remarks by C. B. Stephenson on a spectrogram
obtained by P. Chen on Sept. 3.1 UT with the 91-cm Cassegrain reflector:
"The spectrum shows distinct emission lines, chiefly of H and Fe II,
somewhat asymmetric in shape and with a total width of 3000 km/s. This
width is near but not beyond the upper limit of previously observed nova
spectra. The presence of broad emission in the 4600-4700 A region makes
the overall spectrum resemble McLaughlin's model nova spectrum three
magnitudes below and past maximum light." J. Gallagher and E. P. Ney,
University of Minnesota, communicate: "Infrared photometry of the nova
was obtained on Aug. 30.3 UT using a He-cooled bolometer on the O'Brien
Observatory's 76-cm reflector. Magnitudes are V = 1.8, R = 1.4, I =
1.4, 1.2 at 1.2 um, 0.9 at 1.6 um, 0.8 at 2.2 um, 0.9 at 3.5 um, 0.5
at 4.8 um. This energy distribution is consistent with temperatures
corresponding to an A or F spectral type, which is characteristic of a
galactic nova near maximum light. Since the V point is not depressed
relative to the infrared continuum, it is unlikely that the nova is
heavily reddened by interstellar matter." S. G. Kleinmann, Massachusetts
Institute of Technology, writes: "Infrared photometry at 2.2, 3.5,
5, 8.4, 10.6, 11.1 and 12.6 um of the nova and of the A2 star alpha
Cyg were obtained on Aug. 30.14, 30.25 and 30.28 UT using the 130-cm
telescope and bolometer system at Kitt Peak National Observatory. Both
stars have the same infrared colors, including a weak infrared excess,
with K-N = 0.25. During the period of these observations the infrared
continuum of the nova increased by 0.08 magnitude hr**-1 from a flux
level 0.22 magnitude fainter than alpha Cyg on Aug. 30.14. M. Turner,
X-Ray Astronomy Group, University of Leicester, telexes: "The x-ray flux
from the nova, as measured with the Leicester Sky Survey instrument
on Ariel 5 on Sept. 1.7 UT, is less than 10 Uhuru flux units (3-sigma
upper limit) between 2 and 20 keV. This implies that the ratio of
x-ray to optical luminosity for this nova is 30 million times less
than for A0620-00."
Title: Nova Sagittarii 1975
Authors: Shao, C. Y.; Schwartz, G.; Pesch, P.; Chen, P.; Loucka, L.;
Ake, T.; Krumenaker, L.
Bibcode: 1975IAUC.2813....1S
Altcode:
The following precise position has been measured by C. Y. Shao on a
plate taken by G. Schwartz with the 155-cm reflector at the Harvard
College Observatory's Agassiz Station: R.A. = 17h55m11s.66, Decl. =
-28o21'38".8 (equinox 1950.0). Dr. P. Pesch, Director of the Warner
and Swasey Observatory, reports that an objective-prism spectrogram,
taken on Aug. 1 by P. Chen, L. Loucka, T. Ake and L. Krumenaker with
the Burrell Schmidt telescope, shows very strong H-alpha in emission.