Author name code: kubo
ADS astronomy entries on 2022-09-14
author:"Kubo, Masahito"
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Title: Quiet Sun Center to Limb Variation of the Linear Polarization
Observed by CLASP2 Across the Mg II h and k Lines
Authors: Rachmeler, L. A.; Bueno, J. Trujillo; McKenzie, D. E.;
Ishikawa, R.; Auchère, F.; Kobayashi, K.; Kano, R.; Okamoto,
T. J.; Bethge, C. W.; Song, D.; Ballester, E. Alsina; Belluzzi,
L.; Pino Alemán, T. del; Ramos, A. Asensio; Yoshida, M.; Shimizu,
T.; Winebarger, A.; Kobelski, A. R.; Vigil, G. D.; Pontieu, B. De;
Narukage, N.; Kubo, M.; Sakao, T.; Hara, H.; Suematsu, Y.; Štěpán,
J.; Carlsson, M.; Leenaarts, J.
Bibcode: 2022ApJ...936...67R
Altcode: 2022arXiv220701788R
The CLASP2 (Chromospheric LAyer Spectro-Polarimeter 2) sounding rocket
mission was launched on 2019 April 11. CLASP2 measured the four Stokes
parameters of the Mg II h and k spectral region around 2800 Å along a
200″ slit at three locations on the solar disk, achieving the first
spatially and spectrally resolved observations of the solar polarization
in this near-ultraviolet region. The focus of the work presented here
is the center-to-limb variation of the linear polarization across these
resonance lines, which is produced by the scattering of anisotropic
radiation in the solar atmosphere. The linear polarization signals of
the Mg II h and k lines are sensitive to the magnetic field from the
low to the upper chromosphere through the Hanle and magneto-optical
effects. We compare the observations to theoretical predictions
from radiative transfer calculations in unmagnetized semiempirical
models, arguing that magnetic fields and horizontal inhomogeneities
are needed to explain the observed polarization signals and spatial
variations. This comparison is an important step in both validating and
refining our understanding of the physical origin of these polarization
signatures, and also in paving the way toward future space telescopes
for probing the magnetic fields of the solar upper atmosphere via
ultraviolet spectropolarimetry.
Title: Development of Fast and Precise Scan Mirror Mechanism for an
Airborne Solar Telescope
Authors: Oba, Takayoshi; Shimizu, Toshifumi; Katsukawa, Yukio; Kubo,
Masahito; Kawabata, Yusuke; Hara, Hirohisa; Uraguchi, Fumihiro;
Tsuzuki, Toshihiro; Tamura, Tomonori; Shinoda, Kazuya; Kodeki,
Kazuhide; Fukushima, Kazuhiko; Morales Fernández, José Miguel;
Sánchez Gómez, Antonio; Balaguer Jimenéz, María; Hernández
Expósito, David; Gandorfer, Achim
Bibcode: 2022arXiv220713864O
Altcode:
We developed a scan mirror mechanism (SMM) that enable a slit-based
spectrometer or spectropolarimeter to precisely and quickly map
an astronomical object. The SMM, designed to be installed in the
optical path preceding the entrance slit, tilts a folding mirror
and then moves the reflected image laterally on the slit plane,
thereby feeding a different one-dimensional image to be dispersed by
the spectroscopic equipment. In general, the SMM is required to scan
quickly and broadly while precisely placing the slit position across
the field-of-view (FOV). These performances are highly in demand for
near-future observations, such as studies on the magnetohydrodynamics of
the photosphere and the chromosphere. Our SMM implements a closed-loop
control system by installing electromagnetic actuators and gap-based
capacitance sensors. Our optical test measurements confirmed that the
SMM fulfils the following performance criteria: i) supreme scan-step
uniformity (linearity of 0.08%) across the wide scan range (${\pm}$1005
arcsec), ii) high stability (3${\sigma}$ = 0.1 arcsec), where the
angles are expressed in mechanical angle, and iii) fast stepping speed
(26 ms). The excellent capability of the SMM will be demonstrated
soon in actual use by installing the mechanism for a near-infrared
spectropolarimeter onboard the balloon-borne solar observatory for
the third launch, Sunrise III.
Title: Polarimetric calibration of the Sunrise UV Spectropolarimeter
and Imager
Authors: Iglesias, F. A.; Feller, A.; Gandorfer, A.; Lagg, A.;
Riethmüller, T. L.; Solanki, S. K.; Katsukawa, Y.; Kubo, M.;
Zucarelli, G.; Sanchez, M.; Sunrise Team
Bibcode: 2022BAAA...63..305I
Altcode:
Sunrise is an optical observatory mounted in a stratospheric balloon,
developed to study magnetic fields in the solar atmosphere with very
high resolution. In its third flight, Sunrise carry the Sunrise UV
Spectropolarimeter and Imager (SUSI), that operates in the 313-430 nm
range, covering thousands of spectral lines not accessible from the
ground and thus largely unexplored. SUSI does not include a polarimetric
calibration unit on board. We report about the development status of
SUSI and the preliminary results of its calibration.
Title: Non-Destructive Bulk Elemental Analysis for Stones from
Asteroid Ryugu
Authors: Ninomiya, K.; Osawa, T.; Takahashi, T.; Terada, K.; Miyake,
Y.; Azuma, T.; Chiu, I.; Katsuragawa, M.; Kubo, M. K.; Minami, T.;
Mizumoto, K.; Nagasawa, S.; Shimomura, K.; Takeshita, S.; Taniguchi,
A.; Takeda, S.; Umegaki, I.; Wada, T.; Watanabe, S.; Morita, T.;
Kikuiri, M.; Amano, K.; Kagawa, E.; Yurimoto, H.; Noguchi, T.; Okazaki,
R.; Yabuta, H.; Naraoka, H.; Sakamoto, K.; Tachibana, S.; Watanabe,
S.; Tsuda, Y.; Nakamura, T.
Bibcode: 2022LPICo2678.1932N
Altcode:
Non-destructive bulk elemental analysis using muon for stones of
Ryugu was conducted, and compositions of Ryugu such as C, N, O were
quantitatively determined.
Title: The HST WFC3 IR View Of LBGs In The SSA22 Protocluster
Authors: Monson, E. B.; Lehmer, B. D.; Doore, K.; Eufrasio, R. T.;
Bonine, B.; Alexander, D.; Harrison, C. M.; Kubo, M.; Mantha, K. B.;
Saez, C.; Straughn, A.; Umehata, H.
Bibcode: 2021AAS...23833106M
Altcode:
To investigate the role of mergers in the observed AGN and star
formation enhancement in the z = 3.09 SSA22 protocluster, we have
applied both quantitative (Sérsic-fit and Gini-M20) and visual
morphological classifications to F160W images of protocluster Lyman
break galaxies (LBGs) in the fields of the X-ray protocluster AGN
and z ∼ 3 field LBGs in SSA22 and GOODS-N. We find no statistically
significant differences between the morphologies and merger fractions
of protocluster and field LBGs, though we are limited by small number
statistics in the protocluster. We have also fit the UV-to-near-IR SEDs
of F160W-detected protocluster and field LBGs to characterize their
stellar masses and star formation histories (SFH). We find that the
mean protocluster LBG is by a factor of ∼ 2 times more massive and
more attenuated than the mean z ∼ 3 field LBG. We take our results to
suggest that ongoing mergers are not more common among protocluster LBGs
than field LBGs, though protocluster LBGs appear to be more massive. We
speculate that the larger mass of the protocluster LBGs contributes to
the enhancement of SMBH mass and accretion rate in the protocluster,
which in turn drives the observed protocluster AGN enhancement.
Title: Mapping of Solar Magnetic Fields from the Photosphere to the
Top of the Chromosphere with CLASP2
Authors: McKenzie, D.; Ishikawa, R.; Trujillo Bueno, J.; Auchere, F.;
del Pino Aleman, T.; Okamoto, T.; Kano, R.; Song, D.; Yoshida, M.;
Rachmeler, L.; Kobayashi, K.; Narukage, N.; Kubo, M.; Ishikawa, S.;
Hara, H.; Suematsu, Y.; Sakao, T.; Bethge, C.; De Pontieu, B.; Vigil,
G.; Winebarger, A.; Alsina Ballester, E.; Belluzzi, L.; Stepan, J.;
Asensio Ramos, A.; Carlsson, M.; Leenaarts, J.
Bibcode: 2021AAS...23810603M
Altcode:
Coronal heating, chromospheric heating, and the heating &
acceleration of the solar wind, are well-known problems in solar
physics. Additionally, knowledge of the magnetic energy that
powers solar flares and coronal mass ejections, important drivers
of space weather, is handicapped by imperfect determination of the
magnetic field in the sun's atmosphere. Extrapolation of photospheric
magnetic measurements into the corona is fraught with difficulties and
uncertainties, partly due to the vastly different plasma beta between
the photosphere and the corona. Better results in understanding
the coronal magnetic field should be derived from measurements of
the magnetic field in the chromosphere. To that end, we are pursuing
quantitative determination of the magnetic field in the chromosphere,
where plasma beta transitions from greater than unity to less than
unity, via ultraviolet spectropolarimetry. The CLASP2 mission, flown
on a sounding rocket in April 2019, succeeded in measuring all four
Stokes polarization parameters in UV spectral lines formed by singly
ionized Magnesium and neutral Manganese. Because these ions produce
spectral lines under different conditions, CLASP2 thus was able to
quantify the magnetic field properties at multiple heights in the
chromosphere simultaneously, as shown in the recent paper by Ishikawa
et al. In this presentation we will report the findings of CLASP2,
demonstrating the variation of magnetic fields along a track on
the solar surface and as a function of height in the chromosphere;
and we will illustrate what is next for the CLASP missions and the
demonstration of UV spectropolarimetry in the solar chromosphere.
Title: Meteorological Aspects of Gamma Ray Glows in Winter
Thunderstorms
Authors: Wada, Y.; Enoto, T.; Kubo, M.; Nakazawa, K.; Shinoda, T.;
Yonetoku, D.; Sawano, T.; Yuasa, T.; Ushio, T.; Sato, Y.; Diniz,
G. S.; Tsuchiya, H.
Bibcode: 2021GeoRL..4891910W
Altcode:
During three winter seasons from November 2016 to March 2019, 11
gamma ray glows were detected at a single observation site of our
ground based gamma ray monitoring network in Kanazawa, Japan. These
events are analyzed with observations of an X band radar network,
a ceilometer, a disdrometer, and a weather monitor. All the detected
glows were connected to convective high reflectivity regions of more
than 35 dBZ, developed up to an altitude of >2 km. They were also
accompanied by heavy precipitation of graupels. Therefore, graupels in
the lower layer of thunderclouds that correspond to high reflectivity
regions can form strong electric fields producing gamma ray glows. Also,
these events are compared with a limited sample of nondetection cases,
but no significant differences in meteorological conditions were found
between detection and nondetection cases in the present study.
Title: Mapping solar magnetic fields from the photosphere to the
base of the corona
Authors: Ishikawa, Ryohko; Bueno, Javier Trujillo; del Pino Alemán,
Tanausú; Okamoto, Takenori J.; McKenzie, David E.; Auchère,
Frédéric; Kano, Ryouhei; Song, Donguk; Yoshida, Masaki; Rachmeler,
Laurel A.; Kobayashi, Ken; Hara, Hirohisa; Kubo, Masahito; Narukage,
Noriyuki; Sakao, Taro; Shimizu, Toshifumi; Suematsu, Yoshinori; Bethge,
Christian; De Pontieu, Bart; Dalda, Alberto Sainz; Vigil, Genevieve D.;
Winebarger, Amy; Ballester, Ernest Alsina; Belluzzi, Luca; Štěpán,
Jiří; Ramos, Andrés Asensio; Carlsson, Mats; Leenaarts, Jorrit
Bibcode: 2021SciA....7.8406I
Altcode: 2021arXiv210301583I
Routine ultraviolet imaging of the Sun's upper atmosphere shows the
spectacular manifestation of solar activity; yet we remain blind to
its main driver, the magnetic field. Here we report unprecedented
spectropolarimetric observations of an active region plage and
its surrounding enhanced network, showing circular polarization in
ultraviolet (Mg II $h$ & $k$ and Mn I) and visible (Fe I) lines. We
infer the longitudinal magnetic field from the photosphere to the
very upper chromosphere. At the top of the plage chromosphere the
field strengths reach more than 300 gauss, strongly correlated with
the Mg II $k$ line core intensity and the electron pressure. This
unique mapping shows how the magnetic field couples the different
atmospheric layers and reveals the magnetic origin of the heating in
the plage chromosphere.
Title: SUNRISE Chromospheric Infrared spectroPolarimeter (SCIP)
for SUNRISE III: Scan mirror mechanism
Authors: Oba, Takayoshi; Shimizu, Toshifumi; Katsukawa, Yukio; Kubo,
Masahito; Uraguchi, Fumihiro; Tsuzuki, Toshihiro; Tamura, Tomonori;
Shinoda, Kazuya; Kodeki, Kazuhide; Fukushima, Kazuhiko; Gandorfer,
Achim; del Toro Iniesta, Jose Carlos
Bibcode: 2020SPIE11445E..4FO
Altcode:
The SUNRISE Chromospheric Infrared spectroPolarimeter (SCIP) is a
balloon-borne long-slit spectrograph for SUNRISE III to precisely
measure magnetic fields in the solar atmosphere. The scan mirror
mechanism (SMM) is installed in the optical path to the entrance slit
of the SCIP to move solar images focused on the slit for 2-dimensional
mapping. The SMM is required to have (1) the tilt stability better
than 0.035″ (3σ) on the sky angle for the diffraction-limited
spatial resolution of 0.2″, (2) step response shorter than 32 msec
for rapid scanning observations, and (3) good linearity (i.e. step
uniformity) over the entire field-of-view (60″x60″). To achieve
these performances, we have developed a flight-model mechanism
and its electronics, in which the mirror tilt is controlled by
electromagnetic actuators with a closed-loop feedback logic with
tilt angles from gap-based capacitance sensors. Several optical
measurements on the optical bench verified that the mechanism meets
the requirements. In particular, the tilt stability achives better
than 0.012″ (3σ). Thermal cycling and thermal vacuum tests have
been completed to demonstrate the performance in the vacuum and the
operational temperature range expected in the balloon flight. We
found a small temperature dependence in the step uniformity and this
dependence will be corrected to have 2-demensional maps with the
sub-arcsec spatial accuracy in the data post-processing.
Title: Sunrise Chromospheric Infrared spectroPolarimeter (SCIP)
for SUNRISE III: optical design and performance
Authors: Tsuzuki, Toshihiro; Katsukawa, Yukio; Uraguchi, Fumihiro;
Hara, Hirohisa; Kubo, Masahito; Nodomi, Yoshifumi; Suematsu, Yoshinori;
Kawabata, Yusuke; Shimizu, Toshifumi; Gandorfer, Achim; Feller, Alex;
Grauf, Bianca; Solanki, Sami; Carlos del Toro Iniesta, Jose
Bibcode: 2020SPIE11447E..AJT
Altcode:
The Sunrise Chromospheric Infrared spectroPolarimeter (SCIP) is a
near-IR spectro-polarimeter instrument newly designed for Sunrise III,
which is a balloon-borne solar observatory equipped with a 1 m optical
telescope. To acquire high-quality 3D magnetic and velocity fields,
SCIP selects the two wavelength bands centered at 850 nm and 770 nm,
which contain many spectrum lines that are highly sensitive to magnetic
fields permeating the photosphere and chromosphere. To achieve high
spatial and spectral resolution (0.21 arcsec and 2 × 105),
SCIP optics adopt a quasi-Littrow configuration based on an echelle
grating and two high-order aspheric mirrors. Using different diffraction
orders of the echelle grating, dichroic beam splitter, and polarizing
beam-splitters, SCIP can obtain s- and p-polarization signals in the
two wavelength bands simultaneously within a relatively small space. We
established the wavefront error budget based on tolerance analysis,
surface figure errors, alignment errors, and environmental changes. In
addition, we performed stray light analysis, and designed light traps
and baffles needed to suppress unwanted reflections and diffraction
by the grating. In this paper, we present the details of this optical
system and its performance.
Title: Sunrise Chromospheric Infrared spectroPolarimeter (SCIP)
for SUNRISE III: polarization modulation unit
Authors: Kubo, Masahito; Shimizu, Toshifumi; Katsukawa, Yukio;
Kawabata, Yusuke; Anan, Tetsu; Ichimoto, Kiyoshi; Shinoda, Kazuya;
Tamura, Tomonori; Nodomi, Yoshifumi; Nakayama, Satoshi; Yamada, Takuya;
Tajima, Takao; Nakata, Shimpei; Nakajima, Yoshihito; Okutani, Kousei;
Feller, Alex; del Toro Iniesta, Jose Carlos
Bibcode: 2020SPIE11447E..A3K
Altcode:
Polarization measurements of the solar chromospheric lines at
high precision are key to present and future solar telescopes for
understanding magnetic field structures in the chromosphere. The
Sunrise Chromospheric Infrared spectroPolarimeter (SCIP) for Sunrise
III is a spectropolarimeter with a polarimetric precision of 0.03 %
(1 σ). The key to high-precision polarization measurements using
SCIP is a polarization modulation unit that rotates a waveplate
continuously at a constant speed. The rotating mechanism is a DC
brushless motor originally developed for a future space mission, and
its control logic was originally developed for the sounding rocket
experiment CLASP. Because of our requirement on a speed of rotation
(0.512 s/rotation) that was 10 times faster than that of CLASP, we
optimized the control logic for the required faster rotation. Fast
polarization modulation is essential for investigating the fine-scale
magnetic field structures related to the dynamical chromospheric
phenomena. We have verified that the rotation performance can achieve
the polarization precision of 0.03 % (1 σ) required by SCIP and such
a significant rotation performance is maintained under thermal vacuum
conditions by simulating the environment of the Sunrise III balloon
flight. The waveplate was designed as a pair of two birefringent
plates made of quartz and sapphire to achieve a constant retardation
in a wide wavelength range. We have confirmed that the retardation
is almost constant in the 770 nm and 850nm wavelength bands of SCIP
under the operational temperature conditions.
Title: Sunrise Chromospheric Infrared spectroPolarimeter (SCIP)
for SUNRISE III: opto-mechanical analysis and design
Authors: Uraguchi, Fumihiro; Tsuzuki, Toshihiro; Katsukawa, Yukio;
Hara, Hirohisa; Iwamura, Satoru; Kubo, Masahito; Nodomi, Yoshifumi;
Suematsu, Yoshinori; Kawabata, Yusuke; Shimizu, Toshifumi; Gandorfer,
Achim; del Toro Iniesta, Jose Carlos
Bibcode: 2020SPIE11447E..ABU
Altcode:
The Sunrise Chromospheric Infrared spectroPolarimeter (SCIP) is a
near-IR spectro-polarimeter instrument newly designed for Sunrise III,
a balloon-borne solar observatory with a 1-m diameter telescope. In
order to achieve the strict requirements the SCIP wavefront error, it is
necessary to quantify the errors due to environmen- tal effects such as
gravity and temperature variation under the observation conditions. We
therefore conducted an integrated opto-mechanical analysis incorporating
mechanical and thermal disturbances into a finite element model of
the entire SCIP structure to acquire the nodal displacements of each
optical element, then fed them back to the optical analysis software
in the form of rigid body motion and surface deformation fitted by
polynomials. This method allowed us to determine the error factors
having a significant influence on optical performance. For example,
no significant wavefront degradation was associated with the structural
mountings because the optical element mounts were well designed based
on quasi-kinematic constraints. In contrast, we found that the main
factor affecting wavefront degradation was the rigid body motions of
the optical elements, which must be mini- mized within the allowable
level. Based on these results, we constructed the optical bench using a
sandwich panel as the optical bench consisting of an aluminum-honeycomb
core and carbon fiber reinforced plastic skins with a high stiffness
and low coefficient of thermal expansion. We then confirmed that the
new opto-mechanical model achieved the wavefront error requirement. In
this paper, we report the details of this integrated opto-mechanical
analysis, including the wavefront error budgeting and the design of
the opto-mechanics.
Title: The SUNRISE UV Spectropolarimeter and imager for SUNRISE III
Authors: Feller, Alex; Gandorfer, Achim; Iglesias, Francisco A.;
Lagg, Andreas; Riethmüller, Tino L.; Solanki, Sami K.; Katsukawa,
Yukio; Kubo, Masahito
Bibcode: 2020SPIE11447E..AKF
Altcode:
Sunrise is a balloon-borne solar observatory dedicated to the
investigation of key processes of the magnetic field and the plasma
flows in the lower solar atmosphere. The observatory operates in
the stratosphere at an altitude of around 37 km in order to avoid
image degradation due to turbulence in the Earth's atmosphere and to
access the UV range. The third science flight of Sunrise will carry new
instrumentation which samples the solar spectrum over a broad wavelength
domain from the UV to the near IR and covers an extended height range in
the solar atmosphere. A key feature of the Sunrise UV Spectropolarimeter
and Imager (SUSI) operating between 309 nm and 417 nm, is its capability
to simultaneously record a large number of spectral lines. By combining
the spectral and polarization information of many individual lines
with different formation heights and sensitivities, the accuracy and
the height resolution of the inferred atmospheric parameters can be
significantly increased. The spectral bands of SUSI are selected one
at a time by rotating a diffraction grating with respect to a fixed
polarimetry unit. The spatial and spectral field of view on the 2k x
2k cameras is 59" and 2.0 - 2.3 nm, respectively. A further innovation
is the numerical restoration of the spectrograph scans by means of
synchronized 2D context imaging, a technique that has recently produced
impressive results at ground-based solar observatories.
Title: The Solar-C (EUVST) mission: the latest status
Authors: Shimizu, Toshifumi; Imada, Shinsuke; Kawate, Tomoko; Suematsu,
Yoshinori; Hara, Hirohisa; Tsuzuki, Toshihiro; Katsukawa, Yukio; Kubo,
Masahito; Ishikawa, Ryoko; Watanabe, Tetsuya; Toriumi, Shin; Ichimoto,
Kiyoshi; Nagata, Shin'ichi; Hasegawa, Takahiro; Yokoyama, Takaaki;
Watanabe, Kyoko; Tsuno, Katsuhiko; Korendyke, Clarence M.; Warren,
Harry; De Pontieu, Bart; Boerner, Paul; Solanki, Sami K.; Teriaca,
Luca; Schuehle, Udo; Matthews, Sarah; Long, David; Thomas, William;
Hancock, Barry; Reid, Hamish; Fludra, Andrzej; Auchère, Frederic;
Andretta, Vincenzo; Naletto, Giampiero; Poletto, Luca; Harra, Louise
Bibcode: 2020SPIE11444E..0NS
Altcode:
Solar-C (EUVST) is the next Japanese solar physics mission to
be developed with significant contributions from US and European
countries. The mission carries an EUV imaging spectrometer with
slit-jaw imaging system called EUVST (EUV High-Throughput Spectroscopic
Telescope) as the mission payload, to take a fundamental step towards
answering how the plasma universe is created and evolves and how the
Sun influences the Earth and other planets in our solar system. In
April 2020, ISAS (Institute of Space and Astronautical Science) of JAXA
(Japan Aerospace Exploration Agency) has made the final down-selection
for this mission as the 4th in the series of competitively chosen
M-class mission to be launched with an Epsilon launch vehicle in mid
2020s. NASA (National Aeronautics and Space Administration) has selected
this mission concept for Phase A concept study in September 2019 and
is in the process leading to final selection. For European countries,
the team has (or is in the process of confirming) confirmed endorsement
for hardware contributions to the EUVST from the national agencies. A
recent update to the mission instrumentation is to add a UV spectral
irradiance monitor capability for EUVST calibration and scientific
purpose. This presentation provides the latest status of the mission
with an overall description of the mission concept emphasizing on key
roles of the mission in heliophysics research from mid 2020s.
Title: Sunrise Chromospheric Infrared SpectroPolarimeter (SCIP)
for sunrise III: system design and capability
Authors: Katsukawa, Y.; del Toro Iniesta, J. C.; Solanki, S. K.;
Kubo, M.; Hara, H.; Shimizu, T.; Oba, T.; Kawabata, Y.; Tsuzuki,
T.; Uraguchi, F.; Nodomi, Y.; Shinoda, K.; Tamura, T.; Suematsu,
Y.; Ishikawa, R.; Kano, R.; Matsumoto, T.; Ichimoto, K.; Nagata, S.;
Quintero Noda, C.; Anan, T.; Orozco Suárez, D.; Balaguer Jiménez,
M.; López Jiménez, A. C.; Cobos Carrascosa, J. P.; Feller, A.;
Riethmueller, T.; Gandorfer, A.; Lagg, A.
Bibcode: 2020SPIE11447E..0YK
Altcode:
The Sunrise balloon-borne solar observatory carries a 1 m aperture
optical telescope and provides us a unique platform to conduct
continuous seeing-free observations at UV-visible-IR wavelengths from
an altitude of higher than 35 km. For the next flight planned for
2022, the post-focus instrumentation is upgraded with new spectro-
polarimeters for the near UV (SUSI) and the near-IR (SCIP), whereas
the imaging spectro-polarimeter Tunable Magnetograph (TuMag) is capable
of observing multiple spectral lines within the visible wavelength. A
new spectro-polarimeter called the Sunrise Chromospheric Infrared
spectroPolarimeter (SCIP) is under development for observing near-IR
wavelength ranges of around 770 nm and 850 nm. These wavelength ranges
contain many spectral lines sensitive to solar magnetic fields and
SCIP will be able to obtain magnetic and velocity structures in the
solar atmosphere with a sufficient height resolution by combining
spectro-polarimetric data of these lines. Polarimetric measurements are
conducted using a rotating waveplate as a modulator and polarizing beam
splitters in front of the cameras. The spatial and spectral resolutions
are 0.2" and 2 105, respectively, and a polarimetric sensitivity of
0.03 % (1σ) is achieved within a 10 s integration time. To detect
minute polarization signals with good precision, we carefully designed
the opto-mechanical system, polarization optics and modulation, and
onboard data processing.
Title: Current Status of the Solar-C_EUVST Mission
Authors: Imada, S.; Shimizu, T.; Kawate, T.; Toriumi, S.; Katsukawa,
Y.; Kubo, M.; Hara, H.; Suematsu, Y.; Ichimoto, K.; Watanabe, T.;
Watanabe, K.; Yokoyama, T.; Warren, H.; Long, D.; Harra, L. K.;
Teriaca, L.
Bibcode: 2020AGUFMSH056..05I
Altcode:
Solar-C_EUVST (EUV High-Throughput Spectroscopic Telescope) is designed
to comprehensively understand the energy and mass transfer from the
solar surface to the solar corona and interplanetary space, and to
investigate the elementary processes that take place universally
in cosmic plasmas. As a fundamental step towards answering how the
plasma universe is created and evolves, and how the Sun influences
the Earth and other planets in our solar system, the proposed mission
is designed to comprehensively understand how mass and energy are
transferred throughout the solar atmosphere. Understanding the solar
atmosphere, which connects to the heliosphere via radiation, the solar
wind and coronal mass ejections, and energetic particles is pivotal
for establishing the conditions for life and habitability in the solar
system. The two primary science objectives for Solar-C_EUVST are :
I) Understand how fundamental processes lead to the formation of the
solar atmosphere and the solar wind, II) Understand how the solar
atmosphere becomes unstable, releasing the energy that drives solar
flares and eruptions. Solar-C_EUVST will, A) seamlessly observe all
the temperature regimes of the solar atmosphere from the chromosphere
to the corona at the same time, B) resolve elemental structures of the
solar atmosphere with high spatial resolution and cadence to track their
evolution, and C) obtain spectroscopic information on the dynamics of
elementary processes taking place in the solar atmosphere. In this
talk, we will first discuss the science target of the Solar-C_EUVST,
and then discuss the current status of the Solar-C_EUVST mission.
Title: Examining the Growth of Black Holes in the Protocluster
Environment at z = 3.1: The HST WFC3 IR View of Galaxies in the
SSA22 Protocluster
Authors: Monson, E. B.; Lehmer, B.; Doore, K.; Eufrasio, R.; Bonine,
B.; Alexander, D.; Coppin, K.; Geach, J.; Harrison, C.; Hine, N.;
Matsuda, Y.; Saez, C.; Smail, I.; Stanley, F.; Stott, J.; Straughn,
A.; Rosario, D.; Kubo, M.; Umehata, H.; Mantha, K.
Bibcode: 2020AAS...23537119M
Altcode:
The well-studied z ~ 3 protocluster in the SSA22 field has been shown
to exhibit an elevated fraction of activity by Active Galactic Nuclei
(AGN) compared to fields at similar redshifts. This activity may be
fueled by an increased merger rate, either past or present, among
protocluster members. High resolution near-infrared (NIR) imaging can
be used to characterize the distribution of stellar mass among the
protocluster members, and may detect the disturbed galaxy morphologies
associated with mergers. We have obtained new Hubble WFC3 F160W (~1.6
µm) observations of the SSA22 field centered on previously-identified
protocluster AGN (Lehmer et al. 2009). In this work we use GALFIT and
Gini-M20 analysis of galaxies detected in new and archival
F160W images to characterize the NIR morphologies of SSA22 protocluster
galaxies. We compare the extracted morphologies to galaxies elsewhere
in the SSA22 field and to a sample of Lyman-Break Galaxies (LBGs) in
HDF-N via a GALFIT catalog produced by van der Wel et al. (2012). We
find no statistically significant difference in the NIR morphologies
of protocluster galaxies and their field counterparts. To characterize
the distribution of stellar masses in the protocluster, we fit SEDs to
protocluster LBGs using broadband UV-NIR photometry. We present a new,
publicly available catalog for the SSA22 field, containing our extracted
morphologies as well as archival photometry and spectroscopic redshifts,
where available. Finally, we discuss possible sources of the observed
enhancement of AGN activity in the context of our results.
Title: High-frequency Wave Propagation Along a Spicule Observed
by CLASP
Authors: Yoshida, Masaki; Suematsu, Yoshinori; Ishikawa, Ryohko;
Okamoto, Takenori J.; Kubo, Masahito; Kano, Ryouhei; Narukage,
Noriyuki; Bando, Takamasa; Winebarger, Amy R.; Kobayashi, Ken;
Trujillo Bueno, Javier; Auchère, Frédéric
Bibcode: 2019ApJ...887....2Y
Altcode:
The Chromospheric Lyman-Alpha Spectro-Polarimeter (CLASP) sounding
rocket experiment, launched in 2015 September, observed the hydrogen
Lyα line (121.6 nm) in an unprecedented high temporal cadence of
0.3 s. CLASP performed sit-and-stare observations of the quiet Sun
near the limb for 5 minutes with a slit perpendicular to the limb
and successfully captured an off-limb spicule evolving along the
slit. The Lyα line is well suited for investigating how spicules
affect the corona because it is sensitive to higher temperatures than
other chromospheric lines, owing to its large optical thickness. We
found high-frequency oscillations of the Doppler velocity with periods
of 20-50 s and low-frequency oscillation of periods of ∼240 s on
the spicule. From a wavelet analysis of the time sequence data of
the Doppler velocity, in the early phase of the spicule evolution,
we found that waves with a period of ∼30 s and a velocity amplitude
of 2-3 km s-1 propagated upward along the spicule with a
phase velocity of ∼470 km s-1. In contrast, in the later
phase, possible downward and standing waves with smaller velocity
amplitudes were also observed. The high-frequency waves observed in
the early phase of the spicule evolution would be related with the
dynamics and the formation of the spicules. Our analysis enabled us to
identify the upward, downward, and standing waves along the spicule
and to obtain the velocity amplitude of each wave directly from the
Doppler velocity for the first time. We evaluated the energy flux
by the upward-propagating waves along the spicule, and discussed the
impact to the coronal heating.
Title: Gas filaments of the cosmic web located around active galaxies
in a protocluster
Authors: Umehata, H.; Fumagalli, M.; Smail, I.; Matsuda, Y.;
Swinbank, A. M.; Cantalupo, S.; Sykes, C.; Ivison, R. J.; Steidel,
C. C.; Shapley, A. E.; Vernet, J.; Yamada, T.; Tamura, Y.; Kubo, M.;
Nakanishi, K.; Kajisawa, M.; Hatsukade, B.; Kohno, K.
Bibcode: 2019Sci...366...97U
Altcode: 2019arXiv191001324U
Cosmological simulations predict that the Universe contains a
network of intergalactic gas filaments, within which galaxies form and
evolve. However, the faintness of any emission from these filaments has
limited tests of this prediction. We report the detection of rest-frame
ultraviolet Lyman-α radiation from multiple filaments extending more
than one megaparsec between galaxies within the SSA22 protocluster at
a redshift of 3.1. Intense star formation and supermassive black-hole
activity is occurring within the galaxies embedded in these structures,
which are the likely sources of the elevated ionizing radiation
powering the observed Lyman-α emission. Our observations map the gas
in filamentary structures of the type thought to fuel the growth of
galaxies and black holes in massive protoclusters.
Title: The Solar-C_EUVST mission
Authors: Shimizu, Toshifumi; Imada, Shinsuke; Kawate, Tomoko;
Ichimoto, Kiyoshi; Suematsu, Yoshinori; Hara, Hirohisa; Katsukawa,
Yukio; Kubo, Masahito; Toriumi, Shin; Watanabe, Tetsuya; Yokoyama,
Takaaki; Korendyke, Clarence M.; Warren, Harry P.; Tarbell, Ted; De
Pontieu, Bart; Teriaca, Luca; Schühle, Udo H.; Solanki, Sami; Harra,
Louise K.; Matthews, Sarah; Fludra, A.; Auchère, F.; Andretta, V.;
Naletto, G.; Zhukov, A.
Bibcode: 2019SPIE11118E..07S
Altcode:
Solar-C EUVST (EUV High-Throughput Spectroscopic Telescope) is a
solar physics mission concept that was selected as a candidate for
JAXA competitive M-class missions in July 2018. The onboard science
instrument, EUVST, is an EUV spectrometer with slit-jaw imaging
system that will simultaneously observe the solar atmosphere from the
photosphere/chromosphere up to the corona with seamless temperature
coverage, high spatial resolution, and high throughput for the first
time. The mission is designed to provide a conclusive answer to the
most fundamental questions in solar physics: how fundamental processes
lead to the formation of the solar atmosphere and the solar wind, and
how the solar atmosphere becomes unstable, releasing the energy that
drives solar flares and eruptions. The entire instrument structure
and the primary mirror assembly with scanning and tip-tilt fine
pointing capability for the EUVST are being developed in Japan, with
spectrograph and slit-jaw imaging hardware and science contributions
from US and European countries. The mission will be launched and
installed in a sun-synchronous polar orbit by a JAXA Epsilon vehicle in
2025. ISAS/JAXA coordinates the conceptual study activities during the
current mission definition phase in collaboration with NAOJ and other
universities. The team is currently working towards the JAXA final
down-selection expected at the end of 2019, with strong support from
US and European colleagues. The paper provides an overall description
of the mission concept, key technologies, and the latest status.
Title: UFSS (ultra fine sun sensor): CCD sun sensor with sub-arc
second accuracy for the next solar observing satellite SOLAR-C
Authors: Tsuno, K.; Wada, S.; Ogawa, T.; Shimizu, T.; Hasegawa, T.;
Kubo, M.; Murao, H.; Mizumoto, S.; Fujishima, S.; Toyonaga, K.
Bibcode: 2019SPIE11180E..4OT
Altcode:
The Ultra Fine Sun Sensor (UFSS) on board the HINODE solar observing
satellite is one of the most successful sun sensors. It is the linear
CCD sun sensor with a special detection method using multiple slits,
called the periodic reticle. The angular resolution of 0.14 arcsec
in the noise equivalent angle (NEA) and 1 arcsec stability were
achieved by the sensor head, of 1.2 kg weight. The concept of the
detection method and processing algorithm of the Sun's direction
is described. The system is modeled and the dynamic response of the
system is characterized by the first-order lag system. By utilizing
this characteristic, a resolution improvement three times higher can be
expected by adjusting the parameters with a small modification to the
HINODE UFSS processing algorithm. The design for a new UFSS for the
next generation solar observation satellite, SOLAR-C, shall include
these modifications. The thermomechanical design is also reviewed to
improve stability and a design policy is obtained.
Title: Chromospheric polarimetry through multiline observations of
the 850 nm spectral region III: Chromospheric jets driven by twisted
magnetic fields
Authors: Quintero Noda, C.; Iijima, H.; Katsukawa, Y.; Shimizu,
T.; Carlsson, M.; de la Cruz Rodríguez, J.; Ruiz Cobo, B.; Orozco
Suárez, D.; Oba, T.; Anan, T.; Kubo, M.; Kawabata, Y.; Ichimoto,
K.; Suematsu, Y.
Bibcode: 2019MNRAS.486.4203Q
Altcode: 2019MNRAS.tmp.1081N; 2019arXiv190409151Q
We investigate the diagnostic potential of the spectral lines at 850
nm for understanding the magnetism of the lower atmosphere. For that
purpose, we use a newly developed 3D simulation of a chromospheric
jet to check the sensitivity of the spectral lines to this phenomenon
as well as our ability to infer the atmospheric information through
spectropolarimetric inversions of noisy synthetic data. We start
comparing the benefits of inverting the entire spectrum at 850 nm versus
only the Ca II 8542 Å spectral line. We found a better match of the
input atmosphere for the former case, mainly at lower heights. However,
the results at higher layers were not accurate. After several tests,
we determined that we need to weight more the chromospheric lines
than the photospheric ones in the computation of the goodness of the
fit. The new inversion configuration allows us to obtain better fits and
consequently more accurate physical parameters. Therefore, to extract
the most from multiline inversions, a proper set of weights needs to
be estimated. Besides that, we conclude again that the lines at 850
nm, or a similar arrangement with Ca II 8542 Å plus Zeeman-sensitive
photospheric lines, pose the best-observing configuration for examining
the thermal and magnetic properties of the lower solar atmosphere.
Title: CLASP2: The Chromospheric LAyer Spectro-Polarimeter
Authors: McKenzie, D. E.; Ishikawa, R.; Trujillo Bueno, J.; Auchére,
F.; Rachmeler, L. A.; Kubo, M.; Kobayashi, K.; Winebarger, A. R.;
Bethge, C. W.; Narukage, N.; Kano, R.; Ishikawa, S.; de Pontieu,
B.; Carlsson, M.; Yoshida, M.; Belluzzi, L.; Štěpán, J.; del Pino
Alemán, T.; Alsina Ballester, E.; Asensio Ramos, A.
Bibcode: 2019ASPC..526..361M
Altcode:
The hydrogen Lyman-α line at 121.6 nm and the Mg k line at 279.5
nm are especially relevant for deciphering the magnetic structure
of the chromosphere since their line-center signals are formed in
the chromosphere and transition region, with unique sensitivities to
magnetic fields. We propose the Chromospheric LAyer Spectro-Polarimeter
(CLASP2), to build upon the success of the first CLASP flight, which
measured the linear polarization in H I Lyman-α. The existing CLASP
instrument will be refitted to measure all four Stokes parameters in
the 280 nm range, including variations due to the anisotropic radiation
pumping, the Hanle effect, and the Zeeman effect.
Title: Comparison of Scattering Polarization Signals Observed by
CLASP: Possible Indication of the Hanle Effect
Authors: Ishikawa, R.; Trujillo Bueno, J.; Uitenbroek, H.; Kubo, M.;
Tsuneta, S.; Goto, M.; Kano, R.; Narukage, N.; Bando, T.; Katsukawa,
Y.; Ishikawa, S.; Giono, G.; Suematsu, Y.; Hara, H.; Shimizu, T.;
Sakao, T.; Winebarger, A.; Kobayashi, K.; Cirtain, J.; Champey, P.;
Auchère, F.; Štěpán, J.; Belluzzi, L.; Asensio Ramos, A.; Manso
Sainz, R.; De Pomtieu, B.; Ichimoto, K.; Carlsson, M.; Casini, R.
Bibcode: 2019ASPC..526..305I
Altcode:
The Chromospheric Lyman-Alpha Spectro-Polarimeter (CLASP; Kano et
al. 2012; Kobayashi et al. 2012; Kubo et al. 2014) observed, for the
first time, the linear polarization produced by scattering processes
in the hydrogen Lyman-α (121.57 nm) and Si III (120.56 nm) lines of
the solar disk radiation. The complexity of the observed scattering
polarization (i.e., conspicuous spatial variations in Q/I and U/I
at spatial scales of 10″-20″ and the absence of center-to- limb
variation at the Lyman-α center; see Kano et al. 2017) motivated us
to search for possible hints of the operation of the Hanle effect by
comparing: (a) the Lyman-α line center signal, for which the critical
field strength (BH) for the onset of the Hanle effect is
53 G, (b) the Lyman-α wing, which is insensitive to the Hanle effect,
and (c) the Si III line, whose BH = 290 G. We focus on four
regions with different total unsigned photospheric magnetic fluxes
(estimated from SDO/HMI observations), and compare the corresponding
U/I spatial variations in the Lyman-α wing, Lyman-α center, and Si III
line. The U/I signal in the Lyman-α wing shows an antisymmetric spatial
distribution, which is caused by the presence of a bright structure in
all the selected regions, regardless of the total unsigned photospheric
magnetic flux. In an internetwork region, the Lyman-α center shows an
antisymmetric spatial variation across the selected bright structure,
but it does not show it in other more magnetized regions. In the Si III
line, the spatial variation of U/I deviates from the above-mentioned
antisymmetric shape as the total unsigned photospheric magnetic flux
increases. We argue that a plausible explanation of this differential
behavior is the operation of the Hanle effect. This work, presented
in an oral contribution at this Workshop, has been published on The
Astrophysical Journal (Ishikawa et al. 2017).
Title: Study of the polarization produced by the Zeeman effect in
the solar Mg I b lines
Authors: Quintero Noda, C.; Uitenbroek, H.; Carlsson, M.; Orozco
Suárez, D.; Katsukawa, Y.; Shimizu, T.; Ruiz Cobo, B.; Kubo, M.; Oba,
T.; Kawabata, Y.; Hasegawa, T.; Ichimoto, K.; Anan, T.; Suematsu, Y.
Bibcode: 2018MNRAS.481.5675Q
Altcode: 2018arXiv181001067Q; 2018MNRAS.tmp.2566Q
The next generation of solar observatories aim to understand the
magnetism of the solar chromosphere. Therefore, it is crucial to
understand the polarimetric signatures of chromospheric spectral
lines. For this purpose, we here examine the suitability of the three
Fraunhofer Mg I b1, b2, and b4 lines
at 5183.6, 5172.7, and 5167.3 Å, respectively. We start by describing
a simplified atomic model of only six levels and three line transitions
for computing the atomic populations of the 3p-4s (multiplet number
2) levels involved in the Mg I b line transitions assuming non-local
thermodynamic conditions and considering only the Zeeman effect using
the field-free approximation. We test this simplified atom against
more complex ones finding that, although there are differences in the
computed profiles, they are small compared with the advantages provided
by the simple atom in terms of speed and robustness. After comparing
the three Mg I lines, we conclude that the most capable one is the
b2 line as b1 forms at similar heights and always
shows weaker polarization signals, while b4 is severely
blended with photospheric lines. We also compare Mg I b2
with the K I D1 and Ca II 8542 Å lines finding that the
former is sensitive to the atmospheric parameters at heights that
are in between those covered by the latter two lines. This makes Mg I
b2 an excellent candidate for future multiline observations
that aim to seamlessly infer the thermal and magnetic properties of
different features in the lower solar atmosphere.
Title: CLASP Constraints on the Magnetization and Geometrical
Complexity of the Chromosphere-Corona Transition Region
Authors: Trujillo Bueno, J.; Štěpán, J.; Belluzzi, L.; Asensio
Ramos, A.; Manso Sainz, R.; del Pino Alemán, T.; Casini, R.; Ishikawa,
R.; Kano, R.; Winebarger, A.; Auchère, F.; Narukage, N.; Kobayashi,
K.; Bando, T.; Katsukawa, Y.; Kubo, M.; Ishikawa, S.; Giono, G.; Hara,
H.; Suematsu, Y.; Shimizu, T.; Sakao, T.; Tsuneta, S.; Ichimoto, K.;
Cirtain, J.; Champey, P.; De Pontieu, B.; Carlsson, M.
Bibcode: 2018ApJ...866L..15T
Altcode: 2018arXiv180908865T
The Chromospheric Lyman-Alpha Spectro-Polarimeter (CLASP) is a
suborbital rocket experiment that on 2015 September 3 measured
the linear polarization produced by scattering processes in the
hydrogen Lyα line of the solar disk radiation. The line-center
photons of this spectral line radiation mostly stem from the
chromosphere-corona transition region (TR). These unprecedented
spectropolarimetric observations revealed an interesting surprise,
namely that there is practically no center-to-limb variation (CLV) in
the Q/I line-center signals. Using an analytical model, we first show
that the geometric complexity of the corrugated surface that delineates
the TR has a crucial impact on the CLV of the Q/I and U/I line-center
signals. Second, we introduce a statistical description of the solar
atmosphere based on a 3D model derived from a state-of-the-art radiation
magnetohydrodynamic simulation. Each realization of the statistical
ensemble is a 3D model characterized by a given degree of magnetization
and corrugation of the TR, and for each such realization we solve the
full 3D radiative transfer problem taking into account the impact
of the CLASP instrument degradation on the calculated polarization
signals. Finally, we apply the statistical inference method presented
in a previous paper to show that the TR of the 3D model that produces
the best agreement with the CLASP observations has a relatively weak
magnetic field and a relatively high degree of corrugation. We emphasize
that a suitable way to validate or refute numerical models of the upper
solar chromosphere is by confronting calculations and observations
of the scattering polarization in ultraviolet lines sensitive to the
Hanle effect.
Title: A Statistical Inference Method for Interpreting the CLASP
Observations
Authors: Štěpán, J.; Trujillo Bueno, J.; Belluzzi, L.; Asensio
Ramos, A.; Manso Sainz, R.; del Pino Alemán, T.; Casini, R.; Kano, R.;
Winebarger, A.; Auchère, F.; Ishikawa, R.; Narukage, N.; Kobayashi,
K.; Bando, T.; Katsukawa, Y.; Kubo, M.; Ishikawa, S.; Giono, G.; Hara,
H.; Suematsu, Y.; Shimizu, T.; Sakao, T.; Tsuneta, S.; Ichimoto, K.;
Cirtain, J.; Champey, P.; De Pontieu, B.; Carlsson, M.
Bibcode: 2018ApJ...865...48S
Altcode: 2018arXiv180802725S
On 2015 September 3, the Chromospheric Lyman-Alpha SpectroPolarimeter
(CLASP) successfully measured the linear polarization produced by
scattering processes in the hydrogen Lyα line of the solar disk
radiation, revealing conspicuous spatial variations in the Q/I and U/I
signals. Via the Hanle effect, the line-center Q/I and U/I amplitudes
encode information on the magnetic field of the chromosphere-corona
transition region, but they are also sensitive to the three-dimensional
structure of this corrugated interface region. With the help of a simple
line-formation model, here we propose a statistical inference method
for interpreting the Lyα line-center polarization observed by CLASP.
Title: Sunrise Chromospheric Infrared spectroPolarimeter (SCIP)
for the SUNRISE balloon-borne solar observatory
Authors: Suematsu, Yoshinori; Katsukawa, Yukio; Hara, Hirohisa;
Ichimoto, Kiyoshi; Shimizu, Toshifumi; Kubo, Masahito; Barthol,
Peter; Riethmueller, Tino; Gandorfer, Achim; Feller, Alex; Orozco
Suárez, David; Del Toro Iniesta, Jose Carlos; Kano, Ryouhei; Ishikawa,
Shin-nosuke; Ishikawa, Ryohko; Tsuzuki, Toshihiro; Uraguchi, Fumihiro;
Quintero Noda, Carlos; Tamura, Tomonori; Oba, Takayoshi; Kawabata,
Yusuke; Nagata, Shinichi; Anan, Tetsu; Cobos Carrascosa, Juan Pedro;
Lopez Jimenez, Antonio Carlos; Balaguer Jimenez, Maria; Solanki, Sami
Bibcode: 2018cosp...42E3285S
Altcode:
The SUNRISE balloon-borne solar observatory carries a 1 m aperture
optical telescope, and allows us to perform seeing-free continuous
observations at visible-IR wavelengths from an altitude higher than
35 km. In the past two flights, in 2009 and 2013, observations mainly
focused on fine structures of photospheric magnetic fields. For the
third flight planned for 2021, we are developing a new instrument
for conducting spectro-polarimetry of spectral lines formed over a
larger height range in the solar atmosphere from the photosphere to
the chromosphere. Targets of the spectro-polarimetric observation
are (1) to determine 3D magnetic structure from the photosphere to
the chromosphere, (2) to trace MHD waves from the photosphere to the
chromosphere, and (3) to reveal the mechanism driving chromospheric
jets, by measuring height- and time-dependent velocities and magnetic
fields. To achieve these goals, a spectro-polarimeter called SCIP
(Sunrise Chromospheric Infrared spectroPolarimeter) is designed to
observe near-infrared spectrum lines sensitive to solar magnetic
fields. The spatial and spectral resolutions are 0.2 arcsec and
200,000, respectively, while 0.03% polarimetric sensitivity is
achieved within a 10 sec integration time. The optical system employs
an Echelle grating and off-axis aspheric mirrors to observe the two
wavelength ranges centered at 850 nm and 770 nm simultaneously by
two cameras. Polarimetric measurements are performed using a rotating
waveplate and polarization beam-splitters in front of the cameras. For
detecting minute polarization signals with good precision, we carefully
assess the temperature dependence of polarization optics, and make
the opto-structural design that minimizes the thermal deformation
of the spectrograph optics. Another key technique is to attain good
(better than 30 msec) synchronization among the rotating phase of
the waveplate, read-out timing of cameras, and step timing of a
slit-scanning mirror. On-board accumulation and data processing are
also critical because we cannot store all the raw data read-out from the
cameras. We demonstrate that we can reduce the data down to almost 10%
with loss-less image compression and without sacrificing polarimetric
information in the data. The SCIP instrument is developed by internal
collaboration among Japanese institutes including Japan Aerospace
Exploration Agency (JAXA), the Spanish Sunrise consortium, and the
German Max Planck Institute for Solar System Research (MPS) with a
leadership of the National Astronomical Observatory of Japan (NAOJ).
Title: Current State of UV Spectro-Polarimetry and its Future
Direction
Authors: Ishikawa, Ryohko; Sakao, Taro; Katsukawa, Yukio; Hara,
Hirohisa; Ichimoto, Kiyoshi; Shimizu, Toshifumi; Kubo, Masahito;
Auchere, Frederic; De Pontieu, Bart; Winebarger, Amy; Kobayashi,
. Ken; Kano, Ryouhei; Narukage, Noriyuki; Trujillo Bueno, Javier;
Song, Dong-uk; Manso Sainz, Rafael; Asensio Ramos, Andres; Leenaarts,
Jorritt; Carlsson, Mats; Bando, Takamasa; Ishikawa, Shin-nosuke;
Tsuneta, Saku; Belluzzi, Luca; Suematsu, Yoshinori; Giono, Gabriel;
Yoshida, Masaki; Goto, Motoshi; Del Pino Aleman, Tanausu; Stepan,
Jiri; Okamoto, Joten; Tsuzuki, Toshihiro; Uraguchi, Fumihiro; Champey,
Patrick; Alsina Ballester, Ernest; Casini, Roberto; McKenzie, David;
Rachmeler, Laurel; Bethge, Christian
Bibcode: 2018cosp...42E1564I
Altcode:
To obtain quantitative information on the magnetic field in low beta
regions (i.e., upper chromosphere and above) has been increasingly
important to understand the energetic phenomena of the outer
solar atmosphere such as flare, coronal heating, and the solar wind
acceleration. In the UV range, there are abundant spectral lines that
originate in the upper chromosphere and transition region. However,
the Zeeman effect in these spectral lines does not give rise to easily
measurable polarization signals because of the weak magnetic field
strength and the larger Doppler broadening compared with the Zeeman
effect. Instead, the Hanle effect in UV lines is expected to be a
suitable diagnostic tool of the magnetic field in the upper atmospheric
layers. To investigate the validity of UV spectro-polarimetry and
the Hanle effect, the Chromospheric Lyman-Alpha Spectro-Polarimeter
(CLASP), which is a NASA sounding- rocket experiment, was launched at
White Sands in US on September 3, 2015. During its 5 minutes ballistic
flight, it successfully performed spectro-polarimetric observations
of the hydrogen Lyman-alpha line (121.57 nm) with an unprecedentedly
high polarization sensitivity of 0.1% in this wavelength range. CLASP
observed the linear polarization produced by scattering process in VUV
lines for the first time and detected the polarization signals which
indicate the operation of the Hanle effect. Following the success
of CLASP, we are confident that UV spectro-polarimetry is the way
to proceed, and we are planning the second flight of CLASP (CLASP2:
Chromospheric LAyer SpectroPolarimeter 2). For this second flight we
will carry out spectro-polarimetry in the Mg II h and k lines around
280 nm, with minimum modifications of the CLASP1 instrument. The linear
polarization in the Mg II k line is induced by scattering processes and
the Hanle effect, being sensitive to magnetic field strengths of 5 to 50
G. In addition, the circular polarizations in the Mg II h and k lines
induced by the Zeeman effect can be measurable in at least plage and
active regions. The combination of the Hanle and Zeeman effects could
help us to more reliably infer the magnetic fields of the upper solar
chromosphere. CLASP2 was selected for flight and is being developed for
launch in the spring of 2019.Based on these sounding rocket experiments
(CLASP1 and 2), we aim at establishing the strategy and refining the
instrument concept for future space missions to explore the enigmatic
atmospheric layers via UV spectro-polarimetry.
Title: Getting Ready for the Third Science Flight of SUNRISE
Authors: Barthol, Peter; Katsukawa, Yukio; Lagg, Andreas; Solanki,
Sami K.; Kubo, Masahito; Riethmueller, Tino; Martínez Pillet,
Valentin; Gandorfer, Achim; Feller, Alex; Berkefeld, . Thomas; Orozco
Suárez, David; Del Toro Iniesta, Jose Carlos; Bernasconi, Pietro;
Álvarez-Herrero, Alberto; Quintero Noda, Carlos
Bibcode: 2018cosp...42E.215B
Altcode:
SUNRISE is a balloon-borne, stratospheric solar observatory dedicated
to the investigation of the structure and dynamics of the Sun's
magnetic field and its interaction with convective plasma flows and
waves. The previous science flights of SUNRISE in 2009 and 2013 have
led to many new scientific results, so far described in around 90
refereed publications. This success has shown the huge potential of the
SUNRISE concept and the recovery of the largely intact payload offers
the opportunity for a third flight.The scientific instrumentation of
SUNRISE 3 will have extended capabilities in particular to measure
magnetic fields, plasma velocities and temperatures with increased
sensitivity and over a larger height range in the solar atmosphere, from
the convectively dominated photosphere up to the still poorly understood
chromosphere. The latter is the key interaction region between magnetic
field, waves and radiation and plays a central role in transporting
energy to the outer layers of the solar atmosphere including the
corona.SUNRISE 3 will carry 2 new grating-based spectro-polarimeters
with slit-scanning and context imaging with slitjaw cameras. The
SUNRISE UV Spectro-polarimeter and Imager (SUSI) will explore the rich
near-UV range between 300 nm and 430 nm which is poorly accessible
from the ground. The SUNRISE Chromospheric Infrared spectro-Polarimeter
(SCIP) will sample 2 spectral windows in the near-infrared, containing
many spectral lines highly sensitive to magnetic fields at different
formation heights. In addition to the two new instruments the Imaging
Magnetograph eXperiment (IMaX), an etalon-based tunable filtergraph and
spectro-polarimeter flown on both previous missions, will be upgraded
to IMaX+, enhancing its cadence and giving access to 2 spectral lines
in the visible spectral range. All three instruments will allow
investigating both the photosphere and the chromosphere and will
ideally complement each other in terms of sensitivity, height coverage
and resolution.A new gondola with a sophisticated attitude control
system including roll damping will provide improved pointing/tracking
performance. Upgraded image stabilization with higher bandwidth will
further reduce residual jitter, maximizing the quality of the science
data.SUNRISE 3 is a joint project of the German Max-Planck-Institut für
Sonnensystemforschung together with the Spanish SUNRISE consortium, the
Johns Hopkins University Applied Physics Laboratory, USA, the German
Kiepenheuer Institut für Sonnenphysik, the National Astronomical
Observatory of Japan and the Japan Aerospace eXploraion Agency (JAXA).
Title: Wavefront error measurements and alignment of CLASP2 telescope
with a dual-band pass cold mirror coated primary mirror
Authors: Yoshida, Masaki; Song, Donguk; Ishikawa, Ryoko; Kano, Ryouhei;
Katsukawa, Yukio; Suematsu, Yoshinori; Narukage, Noriyuki; Kubo,
Masahito; Shinoda, Kazuya; Okamoto, Takenori J.; McKenzie, David E.;
Rachmeler, Laurel A.; Auchère, Frédéric; Trujillo Bueno, Javier
Bibcode: 2018SPIE10699E..30Y
Altcode:
"Chromospheric LAyer Spectro-Polarimeter (CLASP2)" is the next sounding
rocket experiment of the "Chromospheric Lyman-Alpha Spectro-Polarimeter
(CLASP)" that succeeded in observing for the first time the linear
polarization spectra in the hydrogen Lyman-α line (121.6 nm) and is
scheduled to be launched in 2019. In CLASP2, we will carry out full
Stokes-vector spectropolarimetric observations in the Mg ii h and k
lines near 280 nm with the spectro-polarimeter (SP), while imaging
observations in the Lyman-α line will be conducted with the slitjaw
optics (SJ). For the wavelength selection of CLASP2, the primary
mirror of the telescope uses a new dual-band pass cold mirror coating
targeting both at 121.6 nm and 280 nm. Therefore, we have to perform
again the alignment of the telescope after the installation of the
recoated primary mirror. Before unmounting the primary mirror from
the telescope structure, we measured the wave-front error (WFE) of the
telescope. The measured WFE map was consistent with what we had before
the CLASP flight, clearly indicating that the telescope alignment has
been maintained even after the flight. After the re-coated primary
mirror was installed the WFE was measured, and coma aberration was
found to be larger. Finally, the secondary mirror shim adjustments
were carried out based on the WFE measurements. In CLASP2 telescope,
we improved a fitting method of WFE map (applying 8th terms circular
Zernike polynomial fitting instead of 37th terms circular Zernike
fitting) and the improved method enables to achieve better performance
than CLASP telescope. Indeed, WFE map obtained after the final shim
adjustment indicated that the required specification (< 5.5 μm
RMS spot radius) that is more stringent than CLASP telescope was met.
Title: Termination of Electron Acceleration in Thundercloud by
Intracloud/Intercloud Discharge
Authors: Wada, Y.; Bowers, G. S.; Enoto, T.; Kamogawa, M.; Nakamura,
Y.; Morimoto, T.; Smith, D. M.; Furuta, Y.; Nakazawa, K.; Yuasa, T.;
Matsuki, A.; Kubo, M.; Tamagawa, T.; Makishima, K.; Tsuchiya, H.
Bibcode: 2018GeoRL..45.5700W
Altcode: 2018arXiv180504721W
An on-ground observation program for high-energy atmospheric phenomena
in winter thunderstorms along the Japan Sea has been performed via
measurements of gamma ray radiation, atmospheric electric field,
and low-frequency radio band. On 11 February 2017, the radiation
detectors recorded gamma ray emission lasting for 75 s, and then
abruptly terminated with a nearby lightning discharge. The gamma ray
spectrum extended up to 20 MeV and was reproduced by a cutoff power
law model with a photon index of 1.36-0.04+0.03, being consistent with
Bremsstrahlung radiation from a thundercloud (known as a gamma-ray glow
or a thunderstorm ground enhancement). The low-frequency radio monitors,
installed ∼50 km away from the gamma ray observation site recorded
leader development of an intracloud/intercloud discharge spreading
over ∼60 km area with a ∼300-ms duration. The timing of the gamma
ray termination coincided with the moment when the leader development
of the intracloud/intercloud discharge passed 0.7 km horizontally
away from the radiation monitors. The intracloud/intercloud discharge
started ∼15 km away from the gamma ray observation site. Therefore,
the glow was terminated by the leader development, while it did not
trigger the lightning discharge in the present case.
Title: Solar polarimetry in the K I D2 line : A novel
possibility for a stratospheric balloon
Authors: Quintero Noda, C.; Villanueva, G. L.; Katsukawa, Y.; Solanki,
S. K.; Orozco Suárez, D.; Ruiz Cobo, B.; Shimizu, T.; Oba, T.; Kubo,
M.; Anan, T.; Ichimoto, K.; Suematsu, Y.
Bibcode: 2018A&A...610A..79Q
Altcode: 2018arXiv180101655Q
Of the two solar lines, K I D1 and D2, almost
all attention so far has been devoted to the D1 line, as
D2 is severely affected by an O2 atmospheric
band. This, however, makes the latter appealing for balloon and space
observations from above (most of) the Earth's atmosphere. We estimate
the residual effect of the O2 band on the K I D2
line at altitudes typical for stratospheric balloons. Our aim is to
study the feasibility of observing the 770 nm window. Specifically,
this paper serves as a preparation for the third flight of the Sunrise
balloon-borne observatory. The results indicate that the absorption
by O2 is still present, albeit much weaker, at the expected
balloon altitude. We applied the obtained O2 transmittance
to K I D2 synthetic polarimetric spectra and found that in
the absence of line-of-sight motions, the residual O2 has
a negligible effect on the K I D2 line. On the other hand,
for Doppler-shifted K I D2 data, the residual O2
might alter the shape of the Stokes profiles. However, the residual
O2 absorption is sufficiently weak at stratospheric levels
that it can be divided out if appropriate measurements are made,
something that is impossible at ground level. Therefore, for the
first time with Sunrise III, we will be able to perform polarimetric
observations of the K I D2 line and, consequently, we will
have improved access to the thermodynamics and magnetic properties of
the upper photosphere from observations of the K I lines.
Title: New Insights into Sunspots Through Hinode Observations
Authors: Kubo, Masahito
Bibcode: 2018ASSL..449..105K
Altcode:
No abstract at ADS
Title: First Ten Years of Hinode Solar On-Orbit Observatory
Authors: Shimizu, Toshifumi; Imada, Shinsuke; Kubo, Masahito
Bibcode: 2018ASSL..449.....S
Altcode:
No abstract at ADS
Title: Deep Submillimeter and Radio Observations in the SSA22
Field. I. Powering Sources and the Lyα Escape Fraction of Lyα Blobs
Authors: Ao, Y.; Matsuda, Y.; Henkel, C.; Iono, D.; Alexander, D. M.;
Chapman, S. C.; Geach, J.; Hatsukade, B.; Hayes, M.; Hine, N. K.;
Kato, Y.; Kawabe, R.; Kohno, K.; Kubo, M.; Lehnert, M.; Malkan, M.;
Menten, K. M.; Nagao, T.; Norris, R. P.; Ouchi, M.; Saito, T.; Tamura,
Y.; Taniguchi, Y.; Umehata, H.; Weiss, A.
Bibcode: 2017ApJ...850..178A
Altcode: 2017arXiv170405101A
We study the heating mechanisms and Lyα escape fractions of 35 Lyα
blobs (LABs) at z ≈ 3.1 in the SSA22 field. Dust continuum sources
have been identified in 11 of the 35 LABs, all with star formation
rates (SFRs) above 100 M ⊙ yr-1. Likely
radio counterparts are detected in 9 out of 29 investigated LABs. The
detection of submillimeter dust emission is more linked to the physical
size of the Lyα emission than to the Lyα luminosities of the LABs. A
radio excess in the submillimeter/radio-detected LABs is common, hinting
at the presence of active galactic nuclei. Most radio sources without
X-ray counterparts are located at the centers of the LABs. However,
all X-ray counterparts avoid the central regions. This may be explained
by absorption due to exceptionally large column densities along the
line-of-sight or by LAB morphologies, which are highly orientation
dependent. The median Lyα escape fraction is about 3% among the
submillimeter-detected LABs, which is lower than a lower limit of
11% for the submillimeter-undetected LABs. We suspect that the large
difference is due to the high dust attenuation supported by the large
SFRs, the dense large-scale environment as well as large uncertainties
in the extinction corrections required to apply when interpreting
optical data.
Title: Chromospheric polarimetry through multiline observations of
the 850-nm spectral region - II. A magnetic flux tube scenario
Authors: Quintero Noda, C.; Kato, Y.; Katsukawa, Y.; Oba, T.; de la
Cruz Rodríguez, J.; Carlsson, M.; Shimizu, T.; Orozco Suárez, D.;
Ruiz Cobo, B.; Kubo, M.; Anan, T.; Ichimoto, K.; Suematsu, Y.
Bibcode: 2017MNRAS.472..727Q
Altcode: 2017arXiv170801333Q
In this publication, we continue the work started in Quintero Noda et
al., examining this time a numerical simulation of a magnetic flux
tube concentration. Our goal is to study if the physical phenomena
that take place in it, in particular, the magnetic pumping, leaves
a specific imprint on the examined spectral lines. We find that the
profiles from the interior of the flux tube are periodically doppler
shifted following an oscillation pattern that is also reflected in
the amplitude of the circular polarization signals. In addition, we
analyse the properties of the Stokes profiles at the edges of the flux
tube discovering the presence of linear polarization signals for the Ca
II lines, although they are weak with an amplitude around 0.5 per cent
of the continuum intensity. Finally, we compute the response functions
to perturbations in the longitudinal field, and we estimate the field
strength using the weak-field approximation. Our results indicate
that the height of formation of the spectral lines changes during the
magnetic pumping process, which makes the interpretation of the inferred
magnetic field strength and its evolution more difficult. These results
complement those from previous works, demonstrating the capabilities and
limitations of the 850-nm spectrum for chromospheric Zeeman polarimetry
in a very dynamic and complex atmosphere.
Title: Solar polarimetry through the K I lines at 770 nm
Authors: Quintero Noda, C.; Uitenbroek, H.; Katsukawa, Y.; Shimizu,
T.; Oba, T.; Carlsson, M.; Orozco Suárez, D.; Ruiz Cobo, B.; Kubo,
M.; Anan, T.; Ichimoto, K.; Suematsu, Y.
Bibcode: 2017MNRAS.470.1453Q
Altcode: 2017arXiv170510002Q
We characterize the K I D1 & D2 lines in
order to determine whether they could complement the 850 nm window,
containing the Ca II infrared triplet lines and several Zeeman sensitive
photospheric lines, that was studied previously. We investigate the
effect of partial redistribution on the intensity profiles, their
sensitivity to changes in different atmospheric parameters, and
the spatial distribution of Zeeman polarization signals employing a
realistic magnetohydrodynamic simulation. The results show that these
lines form in the upper photosphere at around 500 km, and that they
are sensitive to the line-of-sight velocity and magnetic field strength
at heights where neither the photospheric lines nor the Ca II infrared
lines are. However, at the same time, we found that their sensitivity
to the temperature essentially comes from the photosphere. Then, we
conclude that the K I lines provide a complement to the lines in the
850 nm window for the determination of atmospheric parameters in the
upper photosphere, especially for the line-of-sight velocity and the
magnetic field.
Title: CLASP/SJ Observations of Rapid Time Variations in the Lyα
Emission in a Solar Active Region
Authors: Ishikawa, Shin-nosuke; Kubo, Masahito; Katsukawa, Yukio;
Kano, Ryouhei; Narukage, Noriyuki; Ishikawa, Ryohko; Bando, Takamasa;
Winebarger, Amy; Kobayashi, Ken; Trujillo Bueno, Javier; Auchère,
Frédéric
Bibcode: 2017ApJ...846..127I
Altcode:
The Chromospheric Lyα SpectroPolarimeter (CLASP) is a sounding
rocket experiment launched on 2015 September 3 to investigate the
solar chromosphere and transition region. The slit-jaw (SJ) optical
system captured Lyα images with a high time cadence of 0.6 s. From
the CLASP/SJ observations, many variations in the solar chromosphere
and transition region emission with a timescale of <1 minute
were discovered. In this paper, we focus on the active region within
the SJ field of view and investigate the relationship between short
(<30 s) temporal variations in the Lyα emission and the coronal
structures observed by Solar Dynamics Observatory/Atmospheric Imaging
Assembly (AIA). We compare the Lyα temporal variations at the coronal
loop footpoints observed in the AIA 211 Å (≈2 MK) and AIA 171 Å
(≈0.6 MK) channels with those in the regions with bright Lyα features
without a clear association with the coronal loop footpoints. We find
more short (<30 s) temporal variations in the Lyα intensity in the
footpoint regions. Those variations did not depend on the temperature
of the coronal loops. Therefore, the temporal variations in the Lyα
intensity at this timescale range could be related to the heating of
the coronal structures up to temperatures around the sensitivity peak
of 171 Å. No signature was found to support the scenario that these
Lyα intensity variations were related to the nanoflares. Waves or
jets from the lower layers (lower chromosphere or photosphere) are
possible causes for this phenomenon.
Title: CLASP2: The Chromospheric LAyer Spectro-Polarimeter
Authors: Rachmeler, Laurel; E McKenzie, David; Ishikawa, Ryohko;
Trujillo Bueno, Javier; Auchère, Frédéric; Kobayashi, Ken;
Winebarger, Amy; Bethge, Christian; Kano, Ryouhei; Kubo, Masahito;
Song, Donguk; Narukage, Noriyuki; Ishikawa, Shin-nosuke; De Pontieu,
Bart; Carlsson, Mats; Yoshida, Masaki; Belluzzi, Luca; Stepan, Jiri;
del Pino Alemná, Tanausú; Ballester, Ernest Alsina; Asensio Ramos,
Andres
Bibcode: 2017SPD....4811010R
Altcode:
We present the instrument, science case, and timeline of the CLASP2
sounding rocket mission. The successful CLASP (Chromospheric Lyman-Alpha
Spectro-Polarimeter) sounding rocket flight in 2015 resulted in
the first-ever linear polarization measurements of solar hydrogen
Lyman-alpha line, which is sensitive to the Hanle effect and can be used
to constrain the magnetic field and geometric complexity of the upper
chromosphere. Ly-alpha is one of several upper chromospheric lines that
contain magnetic information. In the spring of 2019, we will re-fly
the modified CLASP telescope to measure the full Stokes profile of Mg
II h & k near 280 nm. This set of lines is sensitive to the upper
chromospheric magnetic field via both the Hanle and the Zeeman effects.
Title: Bimodal morphologies of massive galaxies at the core of a
protocluster at z = 3.09 and the strong size growth of a brightest
cluster galaxy
Authors: Kubo, M.; Yamada, T.; Ichikawa, T.; Kajisawa, M.; Matsuda,
Y.; Tanaka, I.; Umehata, H.
Bibcode: 2017MNRAS.469.2235K
Altcode: 2017arXiv170405962K
We present the near-infrared high-resolution imaging of an extremely
dense group of galaxies at the core of the protocluster at z =
3.09 in the SSA22 field by using the adaptive optics AO188 and the
Infrared Camera and Spectrograph on board the Subaru Telescope. The
wide morphological variety of them suggests their ongoing dramatic
evolutions. One of the two quiescent galaxies (QGs), the most massive
one in the group, is a compact elliptical with an effective radius
re = 1.37 ± 0.75 kpc. It supports the two-phase formation
scenario of giant ellipticals today that a massive compact elliptical
is formed at once and evolves in size and stellar mass by a series of
mergers. Since this object is a plausible progenitor of a brightest
cluster galaxy of one of the most massive clusters today, it requires
strong size ( ≳ 10) and stellar mass (∼ four times by z = 0)
growths. Another QG hosts an active galactic nucleus and is fitted
with a model composed from a nuclear component and Sérsic model. It
shows a spatially extended [O III] λ5007 emission line compared to the
continuum emission, plausible evidence of outflows. Massive star-forming
galaxies (SFGs) in the group are two to three times larger than the
field SFGs at similar redshift. Although we obtained the K-band image
deeper than the previous one, we found no new candidate members. This
implies a physical deficiency of low-mass galaxies with stellar mass
M⋆ ≲ 4 × 1010 M⊙ and/or poor
detection completeness of them owing to their diffuse morphologies.
Title: CLASP2: The Chromospheric LAyer Spectro-Polarimeter
Authors: Rachmeler, Laurel A.; McKenzie, D. E.; Ishikawa, R.;
Trujillo-Bueno, J.; Auchere, F.; Kobayashi, K.; Winebarger, A.;
Bethge, C.; Kano, R.; Kubo, M.; Song, D.; Narukage, N.; Ishikawa, S.;
De Pontieu, B.; Carlsson, M.; Yoshida, M.; Belluzzi, L.; Stepan, J.;
del Pino Alemán, T.; Alsina Ballester, E.; Asensio Ramos, A.
Bibcode: 2017shin.confE..79R
Altcode:
We present the instrument, science case, and timeline of the CLASP2
sounding rocket mission. The successful CLASP (Chromospheric Lyman-Alpha
Spectro-Polarimeter) sounding rocket flight in 2015 resulted in
the first-ever linear polarization measurements of solar hydrogen
Lyman-alpha line, which is sensitive to the Hanle effect and can be used
to constrain the magnetic field and geometric complexity of the upper
chromosphere. Ly-alpha is one of several upper chromospheric lines that
contain magnetic information. In the spring of 2019, we will re-fly
the modified CLASP telescope to measure the full Stokes profile of Mg
II h & k near 280 nm. This set of lines is sensitive to the upper
chromospheric magnetic field via both the Hanle and the Zeeman effects.
Title: Indication of the Hanle Effect by Comparing the Scattering
Polarization Observed by CLASP in the Lyα and Si III 120.65 nm Lines
Authors: Ishikawa, R.; Trujillo Bueno, J.; Uitenbroek, H.; Kubo, M.;
Tsuneta, S.; Goto, M.; Kano, R.; Narukage, N.; Bando, T.; Katsukawa,
Y.; Ishikawa, S.; Giono, G.; Suematsu, Y.; Hara, H.; Shimizu, T.;
Sakao, T.; Winebarger, A.; Kobayashi, K.; Cirtain, J.; Champey, P.;
Auchère, F.; Štěpán, J.; Belluzzi, L.; Asensio Ramos, A.; Manso
Sainz, R.; De Pontieu, B.; Ichimoto, K.; Carlsson, M.; Casini, R.
Bibcode: 2017ApJ...841...31I
Altcode:
The Chromospheric Lyman-Alpha Spectro-Polarimeter is a sounding
rocket experiment that has provided the first successful measurement
of the linear polarization produced by scattering processes in
the hydrogen Lyα line (121.57 nm) radiation of the solar disk. In
this paper, we report that the Si III line at 120.65 nm also shows
scattering polarization and we compare the scattering polarization
signals observed in the Lyα and Si III lines in order to search for
observational signatures of the Hanle effect. We focus on four selected
bright structures and investigate how the U/I spatial variations vary
between the Lyα wing, the Lyα core, and the Si III line as a function
of the total unsigned photospheric magnetic flux estimated from Solar
Dynamics Observatory/Helioseismic and Magnetic Imager observations. In
an internetwork region, the Lyα core shows an antisymmetric spatial
variation across the selected bright structure, but it does not show
it in other more magnetized regions. In the Si III line, the spatial
variation of U/I deviates from the above-mentioned antisymmetric
shape as the total unsigned photospheric magnetic flux increases. A
plausible explanation of this difference is the operation of the Hanle
effect. We argue that diagnostic techniques based on the scattering
polarization observed simultaneously in two spectral lines with very
different sensitivities to the Hanle effect, like Lyα and Si III,
are of great potential interest for exploring the magnetism of the
upper solar chromosphere and transition region.
Title: Polarization Calibration of the Chromospheric Lyman-Alpha
SpectroPolarimeter for a 0.1% Polarization Sensitivity in the VUV
Range. Part II: In-Flight Calibration
Authors: Giono, G.; Ishikawa, R.; Narukage, N.; Kano, R.; Katsukawa,
Y.; Kubo, M.; Ishikawa, S.; Bando, T.; Hara, H.; Suematsu, Y.;
Winebarger, A.; Kobayashi, K.; Auchère, F.; Trujillo Bueno, J.;
Tsuneta, S.; Shimizu, T.; Sakao, T.; Cirtain, J.; Champey, P.; Asensio
Ramos, A.; Štěpán, J.; Belluzzi, L.; Manso Sainz, R.; De Pontieu,
B.; Ichimoto, K.; Carlsson, M.; Casini, R.; Goto, M.
Bibcode: 2017SoPh..292...57G
Altcode:
The Chromospheric Lyman-Alpha SpectroPolarimeter is a sounding
rocket instrument designed to measure for the first time the linear
polarization of the hydrogen Lyman-α line (121.6 nm). The instrument
was successfully launched on 3 September 2015 and observations were
conducted at the solar disc center and close to the limb during the
five-minutes flight. In this article, the disc center observations are
used to provide an in-flight calibration of the instrument spurious
polarization. The derived in-flight spurious polarization is consistent
with the spurious polarization levels determined during the pre-flight
calibration and a statistical analysis of the polarization fluctuations
from solar origin is conducted to ensure a 0.014% precision on the
spurious polarization. The combination of the pre-flight and the
in-flight polarization calibrations provides a complete picture of
the instrument response matrix, and a proper error transfer method
is used to confirm the achieved polarization accuracy. As a result,
the unprecedented 0.1% polarization accuracy of the instrument in the
vacuum ultraviolet is ensured by the polarization calibration.
Title: Discovery of Scattering Polarization in the Hydrogen Lyα
Line of the Solar Disk Radiation
Authors: Kano, R.; Trujillo Bueno, J.; Winebarger, A.; Auchère, F.;
Narukage, N.; Ishikawa, R.; Kobayashi, K.; Bando, T.; Katsukawa, Y.;
Kubo, M.; Ishikawa, S.; Giono, G.; Hara, H.; Suematsu, Y.; Shimizu,
T.; Sakao, T.; Tsuneta, S.; Ichimoto, K.; Goto, M.; Belluzzi, L.;
Štěpán, J.; Asensio Ramos, A.; Manso Sainz, R.; Champey, P.;
Cirtain, J.; De Pontieu, B.; Casini, R.; Carlsson, M.
Bibcode: 2017ApJ...839L..10K
Altcode: 2017arXiv170403228K
There is a thin transition region (TR) in the solar atmosphere where
the temperature rises from 10,000 K in the chromosphere to millions
of degrees in the corona. Little is known about the mechanisms that
dominate this enigmatic region other than the magnetic field plays a
key role. The magnetism of the TR can only be detected by polarimetric
measurements of a few ultraviolet (UV) spectral lines, the Lyα line
of neutral hydrogen at 121.6 nm (the strongest line of the solar UV
spectrum) being of particular interest given its sensitivity to the
Hanle effect (the magnetic-field-induced modification of the scattering
line polarization). We report the discovery of linear polarization
produced by scattering processes in the Lyα line, obtained with
the Chromospheric Lyman-Alpha Spectro-Polarimeter (CLASP) rocket
experiment. The Stokes profiles observed by CLASP in quiet regions of
the solar disk show that the Q/I and U/I linear polarization signals are
of the order of 0.1% in the line core and up to a few percent in the
nearby wings, and that both have conspicuous spatial variations with
scales of ∼10 arcsec. These observations help constrain theoretical
models of the chromosphere-corona TR and extrapolations of the
magnetic field from photospheric magnetograms. In fact, the observed
spatial variation from disk to limb of polarization at the line core
and wings already challenge the predictions from three-dimensional
magnetohydrodynamical models of the upper solar chromosphere.
Title: High-Reflectivity Coatings for a Vacuum Ultraviolet
Spectropolarimeter
Authors: Narukage, Noriyuki; Kubo, Masahito; Ishikawa, Ryohko;
Ishikawa, Shin-nosuke; Katsukawa, Yukio; Kobiki, Toshihiko; Giono,
Gabriel; Kano, Ryouhei; Bando, Takamasa; Tsuneta, Saku; Auchère,
Frédéric; Kobayashi, Ken; Winebarger, Amy; McCandless, Jim; Chen,
Jianrong; Choi, Joanne
Bibcode: 2017SoPh..292...40N
Altcode:
Precise polarization measurements in the vacuum ultraviolet (VUV)
region are expected to be a new tool for inferring the magnetic fields
in the upper atmosphere of the Sun. High-reflectivity coatings are key
elements to achieving high-throughput optics for precise polarization
measurements. We fabricated three types of high-reflectivity coatings
for a solar spectropolarimeter in the hydrogen Lyman-α (Lyα ; 121.567
nm) region and evaluated their performance. The first high-reflectivity
mirror coating offers a reflectivity of more than 80 % in Lyα
optics. The second is a reflective narrow-band filter coating that has
a peak reflectivity of 57 % in Lyα , whereas its reflectivity in the
visible light range is lower than 1/10 of the peak reflectivity (∼5
% on average). This coating can be used to easily realize a visible
light rejection system, which is indispensable for a solar telescope,
while maintaining high throughput in the Lyα line. The third is a
high-efficiency reflective polarizing coating that almost exclusively
reflects an s-polarized beam at its Brewster angle of 68° with a
reflectivity of 55 %. This coating achieves both high polarizing power
and high throughput. These coatings contributed to the high-throughput
solar VUV spectropolarimeter called the Chromospheric Lyman-Alpha
SpectroPolarimeter (CLASP), which was launched on 3 September, 2015.
Title: Results and future of CLASP project
Authors: Kubo, Masahito
Bibcode: 2017psio.confE..82K
Altcode:
No abstract at ADS
Title: Polarization Calibration of the Chromospheric Lyman-Alpha
SpectroPolarimeter for a 0.1 % Polarization Sensitivity in the VUV
Range. Part I: Pre-flight Calibration
Authors: Giono, G.; Ishikawa, R.; Narukage, N.; Kano, R.; Katsukawa,
Y.; Kubo, M.; Ishikawa, S.; Bando, T.; Hara, H.; Suematsu, Y.;
Winebarger, A.; Kobayashi, K.; Auchère, F.; Trujillo Bueno, J.
Bibcode: 2016SoPh..291.3831G
Altcode: 2016SoPh..tmp..177G
The Chromospheric Lyman-Alpha SpectroPolarimeter (CLASP) is a sounding
rocket experiment designed to measure for the first time the linear
polarization of the hydrogen Lyman-α line (121.6 nm) and requires
a 0.1 % polarization sensitivity, which is unprecedented for a
spectropolarimeter in the vacuum UV (VUV) spectral range.
Title: Discovery of Ubiquitous Fast-Propagating Intensity Disturbances
by the Chromospheric Lyman Alpha Spectropolarimeter (CLASP)
Authors: Kubo, M.; Katsukawa, Y.; Suematsu, Y.; Kano, R.; Bando,
T.; Narukage, N.; Ishikawa, R.; Hara, H.; Giono, G.; Tsuneta, S.;
Ishikawa, S.; Shimizu, T.; Sakao, T.; Winebarger, A.; Kobayashi, K.;
Cirtain, J.; Champey, P.; Auchère, F.; Trujillo Bueno, J.; Asensio
Ramos, A.; Štěpán, J.; Belluzzi, L.; Manso Sainz, R.; De Pontieu,
B.; Ichimoto, K.; Carlsson, M.; Casini, R.; Goto, M.
Bibcode: 2016ApJ...832..141K
Altcode:
High-cadence observations by the slit-jaw (SJ) optics system of the
sounding rocket experiment known as the Chromospheric Lyman Alpha
Spectropolarimeter (CLASP) reveal ubiquitous intensity disturbances
that recurrently propagate in either the chromosphere or the transition
region or both at a speed much higher than the speed of sound. The
CLASP/SJ instrument provides a time series of two-dimensional images
taken with broadband filters centered on the Lyα line at a 0.6 s
cadence. The multiple fast-propagating intensity disturbances appear in
the quiet Sun and in an active region, and they are clearly detected in
at least 20 areas in a field of view of 527″ × 527″ during the 5
minute observing time. The apparent speeds of the intensity disturbances
range from 150 to 350 km s-1, and they are comparable
to the local Alfvén speed in the transition region. The intensity
disturbances tend to propagate along bright elongated structures away
from areas with strong photospheric magnetic fields. This suggests
that the observed fast-propagating intensity disturbances are related
to the magnetic canopy structures. The maximum distance traveled by
the intensity disturbances is about 10″, and the widths are a few
arcseconds, which are almost determined by a pixel size of 1.″03. The
timescale of each intensity pulse is shorter than 30 s. One possible
explanation for the fast-propagating intensity disturbances observed
by CLASP is magnetohydrodynamic fast-mode waves.
Title: ALMA Observations of Lyα Blob 1: Halo Substructure Illuminated
from Within
Authors: Geach, J. E.; Narayanan, D.; Matsuda, Y.; Hayes, M.;
Mas-Ribas, Ll.; Dijkstra, M.; Steidel, C. C.; Chapman, S. C.; Feldmann,
R.; Avison, A.; Agertz, O.; Ao, Y.; Birkinshaw, M.; Bremer, M. N.;
Clements, D. L.; Dannerbauer, H.; Farrah, D.; Harrison, C. M.; Kubo,
M.; Michałowski, M. J.; Scott, Douglas; Smith, D. J. B.; Spaans,
M.; Simpson, J. M.; Swinbank, A. M.; Taniguchi, Y.; van der Werf,
P.; Verma, A.; Yamada, T.
Bibcode: 2016ApJ...832...37G
Altcode: 2016arXiv160802941G
We present new Atacama Large Millimeter/Submillimeter Array (ALMA)
850 μm continuum observations of the original Lyα Blob (LAB) in
the SSA22 field at z = 3.1 (SSA22-LAB01). The ALMA map resolves the
previously identified submillimeter source into three components
with a total flux density of S 850 = 1.68 ± 0.06 mJy,
corresponding to a star-formation rate of ∼150 M ⊙
yr-1. The submillimeter sources are associated with several
faint (m ≈ 27 mag) rest-frame ultraviolet sources identified in Hubble
Space Telescope Imaging Spectrograph (STIS) clear filter imaging (λ ≈
5850 Å). One of these companions is spectroscopically confirmed with
the Keck Multi-Object Spectrometer For Infra-Red Exploration to lie
within 20 projected kpc and 250 km s-1 of one of the ALMA
components. We postulate that some of these STIS sources represent a
population of low-mass star-forming satellites surrounding the central
submillimeter sources, potentially contributing to their growth and
activity through accretion. Using a high-resolution cosmological
zoom simulation of a 1013 M ⊙ halo at z = 3,
including stellar, dust, and Lyα radiative transfer, we can model
the ALMA+STIS observations and demonstrate that Lyα photons escaping
from the central submillimeter sources are expected to resonantly
scatter in neutral hydrogen, the majority of which is predicted to
be associated with halo substructure. We show how this process gives
rise to extended Lyα emission with similar surface brightness and
morphology to observed giant LABs.
Title: A Resolved Map of the Infrared Excess in a Lyman Break Galaxy
at z = 3
Authors: Koprowski, M. P.; Coppin, K. E. K.; Geach, J. E.; Hine,
N. K.; Bremer, M.; Chapman, S.; Davies, L. J. M.; Hayashino, T.;
Knudsen, K. K.; Kubo, M.; Lehmer, B. D.; Matsuda, Y.; Smith, D. J. B.;
van der Werf, P. P.; Violino, G.; Yamada, T.
Bibcode: 2016ApJ...828L..21K
Altcode: 2016arXiv160805080K
We have observed the dust continuum of 10 z = 3.1 Lyman break galaxies
with the Atacama Large Millimeter/submillimeter Array at ∼450 mas
resolution in Band 7. We detect and resolve the 870 μm emission in
one of the targets with a flux density of S 870 = 192 ±
57 μJy, and measure a stacked 3σ signal of S 870 = 67 ±
23 μJy for the remaining nine. The total infrared luminosities are L
8-1000 = (8.4 ± 2.3) × 1010 L ⊙ for
the detection and L 8-1000 = (2.9 ± 0.9) × 1010
L ⊙ for the stack. With Hubble Space Telescope Advanced
Camera for Surveys I-band imaging we map the rest-frame UV emission
on the same scale as the dust, effectively resolving the “infrared
excess” (IRX = L FIR/L UV) in a normal galaxy
at z = 3. Integrated over the galaxy we measure IRX = 0.56 ± 0.15,
and the galaxy-averaged UV slope is β = -1.25 ± 0.03. This puts the
galaxy a factor of ∼10 below the IRX-β relation for local starburst
nuclei of Meurer et al. However, IRX varies by more than a factor of 3
across the galaxy, and we conclude that the complex relative morphology
of the dust relative to UV emission is largely responsible for the
scatter in the IRX-β relation at high-z. A naive application of a
Meurer-like dust correction based on the UV slope would dramatically
overestimate the total star formation rate, and our results support
growing evidence that when integrated over the galaxy, the typical
conditions in high-z star-forming galaxies are not analogous to those
in the local starburst nuclei used to establish the Meurer relation.
Title: ALMA observations of a z ≈ 3.1 protocluster: star formation
from active galactic nuclei and Lyman-alpha blobs in an overdense
environment
Authors: Alexander, D. M.; Simpson, J. M.; Harrison, C. M.; Mullaney,
J. R.; Smail, I.; Geach, J. E.; Hickox, R. C.; Hine, N. K.; Karim,
A.; Kubo, M.; Lehmer, B. D.; Matsuda, Y.; Rosario, D. J.; Stanley,
F.; Swinbank, A. M.; Umehata, H.; Yamada, T.
Bibcode: 2016MNRAS.461.2944A
Altcode: 2016arXiv160100682A
We exploit Atacama Large Interferometer Array (ALMA) 870 μm
observations to measure the star formation rates (SFRs) of eight X-ray
detected active galactic nuclei (AGNs) in a z ≈ 3.1 protocluster,
four of which reside in extended Lyα haloes (often termed Lyman-alpha
blobs: LABs). Three of the AGNs are detected by ALMA and have implied
SFRs of ≈220-410 M⊙ yr-1; the non-detection of
the other five AGNs places SFR upper limits of ≲210 M⊙
yr-1. The mean SFR of the protocluster AGNs (≈110-210
M⊙ yr-1) is consistent (within a factor of
≈0.7-2.3) with that found for co-eval AGNs in the field, implying
that the galaxy growth is not significantly accelerated in these
systems. However, when also considering ALMA data from the literature,
we find evidence for elevated mean SFRs (up-to a factor of ≈5.9 over
the field) for AGNs at the protocluster core, indicating that galaxy
growth is significantly accelerated in the central regions of the
protocluster. We also show that all of the four protocluster LABs are
associated with an ALMA counterpart within the extent of their Lyα
emission. The SFRs of the ALMA sources within the LABs (≈150-410
M⊙ yr-1) are consistent with those expected
for co-eval massive star-forming galaxies in the field. Furthermore,
the two giant LABs (with physical extents of ≳100 kpc) do not host
more luminous star formation than the smaller LABs, despite being an
order of magnitude brighter in Lyα emission. We use these results to
discuss star formation as the power source of LABs.
Title: Optical alignment of the Chromospheric Lyman-Alpha
Spectro-Polarimeter using sophisticated methods to minimize activities
under vacuum
Authors: Giono, G.; Katsukawa, Y.; Ishikawa, R.; Narukage, N.;
Kano, R.; Kubo, M.; Ishikawa, S.; Bando, T.; Hara, H.; Suematsu, Y.;
Winebarger, A.; Kobayashi, K.; Auchère, F.; Trujillo Bueno, J.
Bibcode: 2016SPIE.9905E..3DG
Altcode:
The Chromospheric Lyman-Alpha Spectro-Polarimeter (CLASP) is a
sounding-rocket instrument developed at the National Astronomical
Observatory of Japan (NAOJ) as a part of an international
collaboration. The instrument main scientific goal is to achieve
polarization measurement of the Lyman-α line at 121.56 nm emitted from
the solar upper-chromosphere and transition region with an unprecedented
0.1% accuracy. The optics are composed of a Cassegrain telescope
coated with a "cold mirror" coating optimized for UV reflection and
a dual-channel spectrograph allowing for simultaneous observation of
the two orthogonal states of polarization. Although the polarization
sensitivity is the most important aspect of the instrument, the spatial
and spectral resolutions of the instrument are also crucial to observe
the chromospheric features and resolve the Ly-α profiles. A precise
alignment of the optics is required to ensure the resolutions, but
experiments under vacuum conditions are needed since Ly-α is absorbed
by air, making the alignment experiments difficult. To bypass this
issue, we developed methods to align the telescope and the spectrograph
separately in visible light. We explain these methods and present
the results for the optical alignment of the CLASP telescope and
spectrograph. We then discuss the combined performances of both parts
to derive the expected resolutions of the instrument, and compare them
with the flight observations performed on September 3rd 2015.
Title: Chromospheric LAyer SpectroPolarimeter (CLASP2)
Authors: Narukage, Noriyuki; McKenzie, David E.; Ishikawa, Ryoko;
Trujillo-Bueno, Javier; De Pontieu, Bart; Kubo, Masahito; Ishikawa,
Shin-nosuke; Kano, Ryouhei; Suematsu, Yoshinori; Yoshida, Masaki;
Rachmeler, Laurel A.; Kobayashi, Ken; Cirtain, Jonathan W.; Winebarger,
Amy R.; Asensio Ramos, Andres; del Pino Aleman, Tanausu; Štępán,
Jiri; Belluzzi, Luca; Larruquert, Juan Ignacio; Auchère, Frédéric;
Leenaarts, Jorrit; Carlsson, Mattias J. L.
Bibcode: 2016SPIE.9905E..08N
Altcode:
The sounding rocket Chromospheric Lyman-Alpha SpectroPolarimeter
(CLASP) was launched on September 3rd, 2015, and successfully detected
(with a polarization accuracy of 0.1 %) the linear polarization signals
(Stokes Q and U) that scattering processes were predicted to produce
in the hydrogen Lyman-alpha line (Lyα 121.567 nm). Via the Hanle
effect, this unique data set may provide novel information about the
magnetic structure and energetics in the upper solar chromosphere. The
CLASP instrument was safely recovered without any damage and we have
recently proposed to dedicate its second flight to observe the four
Stokes profiles in the spectral region of the Mg II h and k lines
around 280 nm; in these lines the polarization signals result from
scattering processes and the Hanle and Zeeman effects. Here we describe
the modifications needed to develop this new instrument called the
"Chromospheric LAyer SpectroPolarimeter" (CLASP2).
Title: Spectro-polarimetric observation in UV with CLASP to probe
the chromosphere and transition region
Authors: Kano, Ryouhei; Ishikawa, Ryohko; Winebarger, Amy R.; Auchère,
Frédéric; Trujillo Bueno, Javier; Narukage, Noriyuki; Kobayashi,
Ken; Bando, Takamasa; Katsukawa, Yukio; Kubo, Masahito; Ishikawa,
Shin-Nosuke; Giono, Gabriel; Hara, Hirohisa; Suematsu, Yoshinori;
Shimizu, Toshifumi; Sakao, Taro; Tsuneta, Saku; Ichimoto, Kiyoshi;
Goto, Motoshi; Cirtain, Jonathan W.; De Pontieu, Bart; Casini, Roberto;
Manso Sainz, Rafael; Asensio Ramos, Andres; Stepan, Jiri; Belluzzi,
Luca; Carlsson, Mats
Bibcode: 2016SPD....4710107K
Altcode:
The Chromospheric Lyman-Alpha Spectro-Polarimeter (CLASP) is a NASA
sounding-rocket experiment that was performed in White Sands in
the US on September 3, 2015. During its 5-minute ballistic flight,
CLASP successfully made the first spectro-polarimetric observation in
the Lyman-alpha line (121.57 nm) originating in the chromosphere and
transition region. Since the Lyman-alpha polarization is sensitive
to magnetic field of 10-100 G by the Hanle effect, we aim to infer
the magnetic field information in such upper solar atmosphere with
this experiment.The obtained CLASP data showed that the Lyman-alpha
scattering polarization is about a few percent in the wings and
the order of 0.1% in the core near the solar limb, as it had been
theoretically predicted, and that both polarization signals have a
conspicuous spatio-temporal variability. CLASP also observed another
upper-chromospheric line, Si III (120.65 nm), whose critical field
strength for the Hanle effect is 290 G, and showed a measurable
scattering polarization of a few % in this line. The polarization
properties of the Si III line could facilitate the interpretation of
the scattering polarization observed in the Lyman-alpha line.In this
presentation, we would like to show how the upper chromosphere and
transition region are seen in the polarization of these UV lines and
discuss the possible source of these complicated polarization signals.
Title: An extremely dense group of massive galaxies at the centre
of the protocluster at z = 3.09 in the SSA22 field
Authors: Kubo, M.; Yamada, T.; Ichikawa, T.; Kajisawa, M.; Matsuda,
Y.; Tanaka, I.; Umehata, H.
Bibcode: 2016MNRAS.455.3333K
Altcode: 2015arXiv151004816K
We report the discovery of an extremely dense group of massive galaxies
at the centre of the protocluster at z = 3.09 in the SSA22 field from
near-infrared spectroscopy conducted with the multi-object infrared
camera and spectrograph (MOIRCS) on the Subaru Telecope. The newly
discovered group comprises seven galaxies confirmed at zspec
≈ 3.09 within 180 kpc, including five massive objects with the
stellar masses larger than 1010.5 M⊙ and
is associated with a bright submillimetre source SSA22-AzTEC14. The
dynamical mass of the group estimated from the line-of-sight velocity
dispersion of the members is Mdyn ∼ 1.6 ± 0.3 ×
1013 M⊙. Such a dense group is expected to be
very rare at high redshift, as we have found only a few comparable
systems in large-volume cosmological simulations. Such rare groups
in simulations are hosted in collapsed haloes with Mvir =
1013.4-1014.0 M⊙ and evolve into
the brightest cluster galaxies (BCGs) of the most massive clusters
at present. The observed AzTEC14 group at z = 3.09 is therefore very
likely to be a proto-BCG in the multiple merger phase. The observed
total stellar mass of the group is 5.8^{+5.1}_{-2.0}× 10^{11} M_{⊙},
which suggests that over half the stellar mass of its descendant had
been formed by z = 3. Moreover, we have identified over two members
for each of the four Lyα blobs (LABs) using our new spectroscopic
data. This verifies our previous argument that many of the LABs in
the SSA22 protocluster associated with multiple developed stellar
components.
Title: Protocluster Survey at z = 2.23: from Herschel to ALMA
Authors: Kato, Y.; Matsuda, Y.; Smail, I.; Swinbank, M.; Alexander,
D.; Geach, J.; Lehmer, B.; Tamura, Y.; Umehata, H.; Kohno, K.; Kubo,
M.; Yamada, T.; Hayashino, T.; Erb, D.; Steidel, C.
Bibcode: 2015ASPC..499...25K
Altcode:
We present results of Herschel/SPIRE observation in 2QZ cluster at
z=2.23. 2QZ cluster is discovered as an overdensity of QSOs and Hα
emitters (HAEs), which was originally identified as a concentration
of 5 QSOs in the 2dF Quasar Redshift survey. We find an overdensity
of SPIRE color selected far-infrared bright galaxies (3.9 σ
compared with COSMOS field) ∼5' west of the HAEs density peak of
in a radius of 6 co-Mpc. This suggests 2QZ cluster is experiencing
enhanced dusty star-formation. However, SPIRE color selection with
S500/S350 vs S350/S250
has a redshift uncertainty, we need spectroscopic observation with
ALMA to confirm the precise redshifts.
Title: ALMA Deep Field in SSA22: A Concentration of Dusty Starbursts
in a z = 3.09 Protocluster Core
Authors: Umehata, H.; Tamura, Y.; Kohno, K.; Ivison, R. J.; Alexander,
D. M.; Geach, J. E.; Hatsukade, B.; Hughes, D. H.; Ikarashi, S.; Kato,
Y.; Izumi, T.; Kawabe, R.; Kubo, M.; Lee, M.; Lehmer, B.; Makiya,
R.; Matsuda, Y.; Nakanishi, K.; Saito, T.; Smail, I.; Yamada, T.;
Yamaguchi, Y.; Yun, M.
Bibcode: 2015ApJ...815L...8U
Altcode: 2015arXiv151008861U
We report the results of 1.‧5 × 3‧ mapping at 1.1 mm with the
Atacama Large Millimeter/submillimeter Array toward the central
region of the z = 3.09 SSA22 protocluster. By combining our source
catalog with archival spectroscopic redshifts, we find that eight
submillimeter galaxies (SMGs) with flux densities, S1.1 mm
= 0.7-6.4 mJy (LIR ∼ 1012.1-1013.1
L⊙) are at z = 3.08-3.10. Not only are these SMGs members
of the protocluster, but they in fact reside within the node at the
junction of the 50 Mpc scale filamentary three-dimensional structure
traced by Lyα emitters in this field. The eight SMGs account for a
star formation rate density (SFRD) ∼10 M⊙ yr-1
Mpc-3 in the node, which is two orders of magnitudes higher
than the global SFRD at this redshift. We find that four of the eight
SMGs host an X-ray-luminous active galactic nucleus. Our results
suggest that the vigorous star formation activity and the growth
of supermassive black holes (SMBHs) occurred simultaneously in the
densest regions at z ∼ 3, which may correspond to the most active
historical phase of the massive galaxy population found in the core
of the clusters in the present universe. Two SMGs are associated with
Lyα blobs, implying that the two populations coexist in high-density
environments for a few cases.
Title: CLASP: A UV Spectropolarimeter on a Sounding Rocket for
Probing theChromosphere-Corona Transition Regio
Authors: Ishikawa, Ryohko; Kano, Ryouhei; Winebarger, Amy; Auchere,
Frederic; Trujillo Bueno, Javier; Bando, Takamasa; Narukage,
Noriyuki; Kobayashi, Ken; Katsukawa, Yukio; Kubo, Masahito; Ishikawa,
Shin-nosuke; Giono, Gabriel; Tsuneta, Saku; Hara, Hirohisa; Suematsu,
Yoshinori; Shimizu, Toshifumi; Sakao, Taro; Ichimoto, Kiyoshi;
Cirtain, Jonathan; De Pontieu, Bart; Casini, Roberto; Manso Sainz,
Rafael; Asensio Ramos, Andres; Stepan, Jiri; Belluzzi, Luca
Bibcode: 2015IAUGA..2254536I
Altcode:
The wish to understand the energetic phenomena of the outer solar
atmosphere makes it increasingly important to achieve quantitative
information on the magnetic field in the chromosphere-corona
transition region. To this end, we need to measure and model the
linear polarization produced by scattering processes and the Hanle
effect in strong UV resonance lines, such as the hydrogen Lyman-alpha
line. A team consisting of Japan, USA, Spain, France, and Norway has
been developing a sounding rocket experiment called the Chromospheric
Lyman-alpha Spectro-Polarimeter (CLASP). The aim is to detect the
scattering polarization produced by anisotropic radiation pumping in
the hydrogen Lyman-alpha line (121.6 nm), and via the Hanle effect to
try to constrain the magnetic field vector in the upper chromosphere
and transition region. In this talk, we will present an overview
of our CLASP mission, its scientific objectives, ground tests made,
and the latest information on the launch planned for the Summer of 2015.
Title: Photospheric Flow Field Related to the Evolution of the Sun's
Polar Magnetic Patches Observed by Hinode Solar Optical Telescope
Authors: Kaithakkal, Anjali John; Suematsu, Y.; Kubo, M.; Iida, Y.;
Shiota, D.; Tsuneta, S.
Bibcode: 2015ApJ...799..139K
Altcode: 2014arXiv1412.8023K
We investigated the role of photospheric plasma motions in the formation
and evolution of polar magnetic patches using time-sequence observations
with high spatial resolution. The observations were obtained with
the spectropolarimeter on board the Hinode satellite. From the
statistical analysis using 75 magnetic patches, we found that they are
surrounded by strong converging, supergranulation associated flows
during their apparent lifetime and that the converging flow around
the patch boundary is better observed in the Doppler velocity profile
in the deeper photosphere. Based on our analysis, we suggest that the
like-polarity magnetic fragments in the polar region are advected and
clustered by photospheric converging flows, thereby resulting in the
formation of polar magnetic patches. Our observations show that, in
addition to direct cancellation, magnetic patches decay by fragmentation
followed by unipolar disappearance or unipolar disappearance without
fragmentation. It is possible that the magnetic patches of existing
polarity fragment or diffuse away into smaller elements and eventually
cancel out with opposite polarity fragments that reach the polar region
around the solar cycle maximum. This could be one of the possible
mechanisms by which the existing polarity decays during the reversal
of the polar magnetic field.
Title: VizieR Online Data Catalog: AzTEC/ASTE 1.1mm survey of SSA22
(Umehata+, 2014)
Authors: Umehata, H.; Tamura, Y.; Kohno, K.; Hatsukade, B.; Scott,
K. S.; Kubo, M.; Yamada, T.; Ivison, R. J.; Cybulski, R.; Aretxaga,
I.; Austermann, J.; Hughes, D. H.; Ezawa, H.; Hayashino, T.; Ikarashi,
S.; Iono, D.; Kawabe, R.; Matsuda, Y.; Matsuo, H.; Nakanishi, K.;
Oshima, T.; Perera, T.; Takata, T.; Wilson, G. W.; Yun, M. S.
Bibcode: 2015yCat..74403462U
Altcode:
We used the AzTEC camera operating at 1.1mm mounted on the ASTE
10-m submillimetre telescope located at Pampa la Bola, near Cerro
Chajnantor in northern Chile. All of the AzTEC/ASTE observations of
SSA22 were carried out at night during 2007 August-September and 2008
August-September. (4 data files).
Title: Strategy for Realizing High-Precision VUV Spectro-Polarimeter
Authors: Ishikawa, R.; Narukage, N.; Kubo, M.; Ishikawa, S.; Kano,
R.; Tsuneta, S.
Bibcode: 2014SoPh..289.4727I
Altcode: 2014SoPh..tmp..116I
Spectro-polarimetric observations in the vacuum ultraviolet (VUV)
range are currently the only means to measure magnetic fields in the
upper chromosphere and transition region of the solar atmosphere. The
Chromospheric Lyman-Alpha Spectro-Polarimeter (CLASP) aims to measure
linear polarization at the hydrogen Lyman-α line (121.6 nm). This
measurement requires a polarization sensitivity better than 0.1 %,
which is unprecedented in the VUV range. We here present a strategy with
which to realize such high-precision spectro-polarimetry. This involves
the optimization of instrument design, testing of optical components,
extensive analyses of polarization errors, polarization calibration
of the instrument, and calibration with onboard data. We expect that
this strategy will aid the development of other advanced high-precision
polarimeters in the UV as well as in other wavelength ranges.
Title: Precision VUV Spectro-Polarimetry for Solar Chromospheric
Magnetic Field Measurements
Authors: Ishikawa, R.; Bando, T.; Hara, H.; Ishikawa, S.; Kano, R.;
Kubo, M.; Katsukawa, Y.; Kobiki, T.; Narukage, N.; Suematsu, Y.;
Tsuneta, S.; Aoki, K.; Miyagawa, K.; Ichimoto, K.; Kobayashi, K.;
Auchère, F.; Clasp Team
Bibcode: 2014ASPC..489..319I
Altcode:
The Chromospheric Lyman-Alpha Spectro-Polarimeter (CLASP) is a VUV
spectro-polarimeter optimized for measuring the linear polarization
of the Lyman-α line (121.6 nm) to be launched in 2015 with NASA's
sounding rocket (Ishikawa et al. 2011; Narukage et al. 2011; Kano et
al. 2012; Kobayashi et al. 2012). With this experiment, we aim to (1)
observe the scattering polarization in the Lyman-α line, (2) detect
the Hanle effect, and (3) assess the magnetic fields in the upper
chromosphere and transition region for the first time. The polarization
measurement error consists of scale error δ a (error in amplitude
of linear polarization), azimuth error Δφ (error in the direction
of linear polarization), and spurious polarization ɛ (false linear
polarization signals). The error ɛ should be suppressed below 0.1%
in the Lyman-α core (121.567 nm ±0.02 nm), and 0.5% in the Lyman-α
wing (121.567 nm ±0.05 nm), based on our scientific requirements shown
in Table 2 of Kubo et al. (2014). From scientific justification, we
adopt Δ φ<2° and δ a<10% as the instrument requirements. The
spectro-polarimeter features a continuously rotating MgF2
waveplate (Ishikawa et al. 2013), a dual-beam spectrograph with a
spherical grating working also as a beam splitter, and two polarization
analyzers (Bridou et al. 2011), which are mounted at 90 degree from
each other to measure two orthogonal polarization simultaneously. For
the optical layout of the CLASP instrument, see Figure 3 in Kubo et
al. (2014). Considering the continuous rotation of the half-waveplate,
the modulation efficiency is 0.64 both for Stokes Q and U. All the raw
data are returned and demodulation (successive addition or subtraction
of images) is done on the ground. We control the CLASP polarization
performance in the following three steps. First, we evaluate the
throughput and polarization properties of each optical component in
the Lyman-α line, using the Ultraviolet Synchrotron ORbital Radiation
Facility (UVSOR) at the Institute for Molecular Science. The second
step is polarization calibration of the spectro-polarimeter after
alignment. Since the spurious polarization caused by the axisymmetric
telescope is estimated to be negligibly small because of the symmetry
(Ishikawa et al. 2014), we do not perform end-to-end polarization
calibration. As the final step, before the scientific observation near
the limb, we make a short observation at the Sun center and verify
the polarization sensitivity, because the scattering polarization
is expected to be close to zero at the Sun center due to symmetric
geometry. In order to clarify whether we will be able to achieve the
required polarization sensitivity and accuracy via these steps, we
exercise polarization error budget, by investigating all the possible
causes and their magnitudes of polarization errors, all of which are not
necessarily verified by the polarization calibration. Based on these
error budgets, we conclude that a polarization sensitivity of 0.1% in
the line core, δ a<10% and Δ φ<2° can be achieved combined
with the polarization calibration of the spectro-polarimeter and the
onboard calibration at the Sun center(refer to Ishikawa et al. 2014,
for the detail). We are currently conducting verification tests
of the flight components and development of the UV light source for
the polarization calibration. From 2014 spring, we will begin the
integration, alignment, and calibration. We will update the error
budgets throughout the course of these tests.
Title: A Sounding Rocket Experiment for the Chromospheric Lyman-Alpha
Spectro-Polarimeter (CLASP)
Authors: Kubo, M.; Kano, R.; Kobayashi, K.; Bando, T.; Narukage, N.;
Ishikawa, R.; Tsuneta, S.; Katsukawa, Y.; Ishikawa, S.; Suematsu, Y.;
Hara, H.; Shimizu, T.; Sakao, T.; Ichimoto, K.; Goto, M.; Holloway,
T.; Winebarger, A.; Cirtain, J.; De Pontieu, B.; Casini, R.; Auchère,
F.; Trujillo Bueno, J.; Manso Sainz, R.; Belluzzi, L.; Asensio Ramos,
A.; Štěpán, J.; Carlsson, M.
Bibcode: 2014ASPC..489..307K
Altcode:
A sounding-rocket experiment called the Chromospheric Lyman-Alpha
Spectro-Polarimeter (CLASP) is presently under development to measure
the linear polarization profiles in the hydrogen Lyman-alpha (Lyα)
line at 121.567 nm. CLASP is a vacuum-UV (VUV) spectropolarimeter to aim
for first detection of the linear polarizations caused by scattering
processes and the Hanle effect in the Lyα line with high accuracy
(0.1%). This is a fist step for exploration of magnetic fields in
the upper chromosphere and transition region of the Sun. Accurate
measurements of the linear polarization signals caused by scattering
processes and the Hanle effect in strong UV lines like Lyα are
essential to explore with future solar telescopes the strength
and structures of the magnetic field in the upper chromosphere and
transition region of the Sun. The CLASP proposal has been accepted by
NASA in 2012, and the flight is planned in 2015.
Title: Unresolved Mixed Polarity Magnetic Fields at Flux Cancellation
Site in Solar Photosphere at 0.''3 Spatial Resolution
Authors: Kubo, Masahito; Chye Low, Boon; Lites, Bruce W.
Bibcode: 2014ApJ...793L...9K
Altcode: 2014arXiv1408.5796K
This is a follow-up investigation of a magnetic flux cancellation
event at a polarity inversion line (PIL) on the Sun observed with the
spectropolarimeter on board Hinode. Anomalous circular polarization
(Stokes V) profiles are observed in the photosphere along the PIL
at the cancellation sites. Kubo et al. previously reported that
the theoretically expected horizontal fields between the canceling
opposite-polarity magnetic elements in this event are not detected at
granular scales. We show that the observed anomalous Stokes V profiles
are reproduced successfully by adding the nearly symmetric Stokes
V profiles observed at pixels immediately adjacent to the PIL. This
result suggests that these observed anomalous Stokes V profiles are not
indications of a flux removal process, but are the result of either
a mixture of unresolved, opposite-polarity magnetic elements or the
unresolved width of the PIL, at an estimated resolution element of
about 0.''3. The hitherto undetected flux removal process accounting
for the larger-scale disappearance of magnetic flux during the observing
period is likely to also fall below resolution.
Title: AzTEC/ASTE 1.1-mm survey of SSA22: Counterpart identification
and photometric redshift survey of submillimetre galaxies
Authors: Umehata, H.; Tamura, Y.; Kohno, K.; Hatsukade, B.; Scott,
K. S.; Kubo, M.; Yamada, T.; Ivison, R. J.; Cybulski, R.; Aretxaga,
I.; Austermann, J.; Hughes, D. H.; Ezawa, H.; Hayashino, T.; Ikarashi,
S.; Iono, D.; Kawabe, R.; Matsuda, Y.; Matsuo, H.; Nakanishi, K.;
Oshima, T.; Perera, T.; Takata, T.; Wilson, G. W.; Yun, M. S.
Bibcode: 2014MNRAS.440.3462U
Altcode: 2014arXiv1403.2725U
We present the results from a 1.1-mm imaging survey of the SSA22 field,
known for having an overdensity of z = 3.1 Lyman α emitting galaxies
(LAEs), taken with the astronomical thermal emission camera (AzTEC)
on the Atacama Submillimeter Telescope Experiment (ASTE). We imaged
a 950-arcmin2 field down to a 1σ sensitivity of 0.7-1.3
mJy beam-1 to find 125 submillimetre galaxies (SMGs) with a
signal-to-noise ratio ≥3.5. Counterpart identification using radio
and near/mid-infrared data was performed and one or more counterpart
candidates were found for 59 SMGs. Photometric redshifts based on
optical to near-infrared images were evaluated for 45 of these SMGs
with Spitzer/IRAC data and the median value is found to be z = 2.4. By
combining these estimations with estimates from the literature, we
determined that 10 SMGs might lie within the large-scale structure
at z = 3.1. The two-point angular cross-correlation function between
LAEs and SMGs indicates that the positions of the SMGs are correlated
with the z = 3.1 protocluster. These results suggest that the SMGs
were formed and evolved selectively in the high dense environment
of the high-redshift Universe. This picture is consistent with the
predictions of the standard model of hierarchical structure formation.
Title: Molecular and lipid biomarker analysis of a gypsum-hosted
endoevaporitic microbial community
Authors: Jahnke, L. L.; Turk-Kubo, K. A.; Parenteau, M. N.; Green,
S. J.; Kubo, M. D. Y.; Vogel, M.; Summons, R. E.; Des Marais, D. J.
Bibcode: 2014GeoBi..12...62J
Altcode:
Modern evaporitic microbial ecosystems are important analogs
for understanding the record of earliest life on Earth. Although
mineral-depositing shallow-marine environments were prevalent during
the Precambrian, few such environments are now available today for
study. We investigated the molecular and lipid biomarker composition of
an endoevaporitic gypsarenite microbial mat community in Guerrero Negro,
Mexico. The 16S ribosomal RNA gene-based phylogenetic analyses of this
mat corroborate prior observations indicating that characteristic
layered microbial communities colonize gypsum deposits world-wide
despite considerable textural and morphological variability. Membrane
fatty acid analysis of the surface tan/orange and lower green
mat crust layers indicated cell densities of 1.6 × 109 and 4.2
× 109 cells cm−3, respectively. Several biomarker fatty acids,
∆7,10-hexadecadienoic, iso-heptadecenoic, 10-methylhexadecanoic,
and a ∆12-methyloctadecenoic, correlated well with distributions of
Euhalothece, Stenotrophomonas, Desulfohalobium, and Rhodobacterales,
respectively, revealed by the phylogenetic analyses. Chlorophyll
(Chl) a and cyanobacterial phylotypes were present at all depths in
the mat. Bacteriochlorophyl (Bchl) a and Bchl c were first detected in
the oxic-anoxic transition zone and increased with depth. A series of
monomethylalkanes (MMA), 8-methylhexadecane, 8-methylheptadecane, and
9-methyloctadecane were present in the surface crust but increased in
abundance in the lower anoxic layers. The MMA structures are similar to
those identified previously in cultures of the marine Chloroflexus-like
organism 'Candidatus Chlorothrix halophila' gen. nov., sp. nov., and may
represent the Bchl c community. Novel 3-methylhopanoids were identified
in cultures of marine purple non-sulfur bacteria and serve as a probable
biomarker for this group in the lower anoxic purple and olive-black
layers. Together microbial culture and environmental analyses support
novel sources for lipid biomarkers in gypsum crust mats.
Title: Chromospheric Lyman-alpha spectro-polarimeter (CLASP)
Authors: Kano, Ryouhei; Katsukawa, Yukio; Kubo, Masahito; Auchere,
Frederic; Ishikawa, Ryohko; Kobayashi, Ken; Narukage, Noriyuki;
Trujillo Bueno, Javier; Bando, Takamasa; Ishikawa, Shin-nosuke
Bibcode: 2014cosp...40E1383K
Altcode:
In the solar chromosphere, magneto-hydrodynamic waves and super-sonic
jets ubiquitously happen as revealed by the Japanese solar satellite
Hinode. Now, we understand that the solar chromosphere is not a simple
intermediate layer smoothly connecting the photosphere and corona,
but a site where those dynamics may play an important role in the
chromospheric and coronal heating. Such discoveries imply that the
next frontier in solar physics lies in simultaneous observations
between the dynamics and magnetic structures in the chromosphere and
transition region, where the gas-dominant photosphere changes to the
magnetic-dominant corona. Therefore, we promote the Chromospheric
Lyman-Alpha SpectroPolarimeter (CLASP), which is a NASA's sounding
rocket experiment scheduled in 2015 for aiming to infer the magnetic
field information in the solar chromosphere and transition region. CLASP
makes precise measurement (0.1%) of the polarization profile of the
Lyman-alpha line, and aims to make the first ever measurement of the
Hanle effect polarization caused by magnetic fields in the upper solar
atmosphere. It is also a pathfinder to establish a new measurement
tool for chromospheric and transition-region magnetic fields, and to
make progress on chromospheric studies in future missions.
Title: UV spectropolarimeter design for precise polarization
measurement and its application to the CLASP for exploration of
magnetic fields in solar atmosphere
Authors: Narukage, Noriyuki; Katsukawa, Yukio; Hara, Hirohisa; Kubo,
Masahito; Auchere, Frederic; Ishikawa, Ryohko; Kano, Ryouhei; Bando,
Takamasa; Ishikawa, Shin-nosuke; Suematsu, Yoshinori; Tsuneta, Saku
Bibcode: 2014cosp...40E2232N
Altcode:
In order to measure the magnetic field in the region where the
hot plasma from 10 (4) K to 10 (6) K is occupied, e.g., for solar
atmosphere, the polarimetric measurements in ultra violet (UV)
with 0.1% accuracy are required. In this paper, we propose a new
UV spectropolarimeter design with 0.1% sensitivity in polarization
measurement. This spectropolarimeter has two devices for the 0.1%
accuracy. First, all optical components except the waveplate are the
reflective type ones that can be equipped with the high reflectivity
coating for the high throughput. Secondly, it equips the optically
symmetric dual channels to measure the orthogonal linear polarization
state simultaneously, using a concave diffraction grating as both the
spectral dispersion element and the beam splitter. These two devices
make the spurious polarizations caused by the photon noise, by the
intensity variation of the observation target, and, by the instrument
itself, enough small to achieve the 0.1% accuracy in polarization
measurement. The spectropolarimeter thus designed is currently under
fabrication for the sounding rocket project of Chromospheric Lyman-Alpha
SpectroPolarimeter (CLASP) that aims at the direct measurement of the
magnetic fields in solar atmosphere with Lyman-alpha line (121.6 nm)
for the first time.
Title: The Formation of the Massive Galaxies in the SSA22 z =
3.1 Protocluster
Authors: Kubo, M.; Uchimoto, Y. K.; Yamada, T.; Kajisawa, M.; Ichikawa,
T.; Matsuda, Y.; Akiyama, M.; Hayashino, T.; Konishi, M.; Nishimura,
T.; Omata, K.; Suzuki, R.; Tanaka, I.; Yoshikawa, T.; Alexander,
D. M.; Fazio, G. G.; Huang, J. -S.; Lehmer, B. D.
Bibcode: 2013ApJ...778..170K
Altcode: 2013arXiv1310.2020K
We study the properties of K-band-selected galaxies (K AB
< 24) in the z = 3.09 SSA22 protocluster field. 430 galaxies at 2.6
< z phot < 3.6 are selected as potential protocluster
members in a 112 arcmin2 area based on their photometric
redshifts. We find that ≈20% of the massive galaxies with stellar
masses >1011 M ⊙ at z phot
~ 3.1 have colors consistent with those of quiescent galaxies with
ages >0.5 Gyr. This fraction increases to ≈50% after correcting
for unrelated foreground/background objects. We also find that 30%
of the massive galaxies are heavily reddened, dusty, star-forming
galaxies. Few such quiescent galaxies at similar redshifts are seen in
typical survey fields. An excess surface density of 24 μm sources at z
phot ~ 3.1 is also observed, implying the presence of dusty
star-formation activity in the protocluster. Cross-correlation with the
X-ray data indicates that the fraction of K-band-selected protocluster
galaxies hosting active galactic nuclei (AGNs) is also high compared
with the field. The sky distribution of the quiescent galaxies, the
24 μm sources, and the X-ray AGNs show clustering around a density
peak of z = 3.1 Lyα emitters. A significant fraction of the massive
galaxies have already become quiescent, while dusty star-formation is
still active in the SSA22 protocluster. These findings indicate that
we are witnessing the formation epoch of massive early-type galaxies
in the centers of the predecessors to present-day rich galaxy clusters.
Title: The Association of Polar Faculae with Polar Magnetic Patches
Examined with Hinode Observations
Authors: Kaithakkal, Anjali John; Suematsu, Y.; Kubo, M.; Shiota,
D.; Tsuneta, S.
Bibcode: 2013ApJ...776..122K
Altcode: 2013arXiv1311.0980K
The magnetic properties of the Sun's polar faculae are investigated with
spectropolarimetric observations of the north polar region obtained by
the Hinode satellite in 2007 September. Polar faculae are embedded in
nearly all magnetic patches with fluxes greater than 1018
Mx, while magnetic patches without polar faculae dominate in the flux
range below 1018 Mx. The faculae are considerably smaller
than their parent patches, and single magnetic patches contain single
or multiple faculae. The faculae in general have higher intrinsic
magnetic field strengths than the surrounding regions within their
parent patches. Less than 20% of the total magnetic flux contributed
by the large (>=1018 Mx) concentrations, which are known
to be modulated by the solar cycle, is accounted for by the associated
polar faculae.
Title: Chromospheric Lyman Alpha SpectroPolarimeter: CLASP
Authors: Kobayashi, Ken; Kano, R.; Trujillo Bueno, J.; Winebarger,
A. R.; Cirtain, J. W.; Bando, T.; De Pontieu, B.; Ishikawa, R.;
Katsukawa, Y.; Kubo, M.; Narukage, N.; Sakao, T.; Tsuneta, S.;
Auchère, F.; Asensio Ramos, A.; Belluzzi, L.; Carlsson, M.; Casini,
R.; Hara, H.; Ichimoto, K.; Manso Sainz, R.; Shimizu, T.; Stepan,
J.; Suematsu, Y.; Holloway, T.
Bibcode: 2013SPD....44..142K
Altcode:
The Chromospheric Lyman-Alpha Spectro-Polarimeter (CLASP) is a VUV
spectropolarimeter optimized for measuring the linear polarization of
the Lyman-alpha line (121.6 nm). The Lyman-alpha line is predicted to
show linear polarization caused by atomic scattering in the chromosphere
and modified by the magnetic field through the Hanle effect. The
Hanle effect is sensitive to weaker magnetic fields than Zeeman
effect, and is not canceled by opposing fields, making it sensitive
to tangled or unresolved magnetic field structures. These factors make
the Hanle effect a valuable tool for probing the magnetic field in the
chromosphere above the quiet sun. To meet this goal, CLASP is designed
to measure linear polarization with 0.1% polarization sensitivity
at 0.01 nm spectral resolution and 10" spatial resolution. CLASP is
scheduled to be launched in 2015.
Title: The Hinode Spectro-Polarimeter
Authors: Lites, B. W.; Akin, D. L.; Card, G.; Cruz, T.; Duncan, D. W.;
Edwards, C. G.; Elmore, D. F.; Hoffmann, C.; Katsukawa, Y.; Katz, N.;
Kubo, M.; Ichimoto, K.; Shimizu, T.; Shine, R. A.; Streander, K. V.;
Suematsu, A.; Tarbell, T. D.; Title, A. M.; Tsuneta, S.
Bibcode: 2013SoPh..283..579L
Altcode:
The joint Japan/US/UK Hinode mission includes the first large-aperture
visible-light solar telescope flown in space. One component of the
Focal Plane Package of that telescope is a precision spectro-polarimeter
designed to measure full Stokes spectra with the intent of using those
spectra to infer the magnetic-field vector at high precision in the
solar photosphere. This article describes the characteristics of the
flight hardware of the HinodeSpectro-Polarimeter, and summarizes its
in-flight performance.
Title: Next space solar observatory SOLAR-C: mission instruments
and science objectives
Authors: Katsukawa, Y.; Watanabe, T.; Hara, H.; Ichimoto, K.; Kubo,
M.; Kusano, K.; Sakao, T.; Shimizu, T.; Suematsu, Y.; Tsuneta, S.
Bibcode: 2012IAUSS...6E.207K
Altcode:
SOLAR-C, the fourth space solar mission in Japan, is under study with a
launch target of fiscal year 2018. A key concept of the mission is to
view the photosphere, chromosphere, and corona as one system coupled
by magnetic fields along with resolving the size scale of fundamental
physical processes connecting these atmospheric layers. It is especially
important to study magnetic structure in the chromosphere as an
interface layer between the photosphere and the corona. The SOLAR-C
satellite is equipped with three telescopes, the Solar UV-Visible-IR
Telescope (SUVIT), the EUV/FUV High Throughput Spectroscopic Telescope
(EUVS/LEMUR), and the X-ray Imaging Telescope (XIT). Observations
with SUVIT of photospheric and chromospheric magnetic fields make it
possible to infer three dimensional magnetic structure extending from
the photosphere to the chromosphere and corona.This helps to identify
magnetic structures causing magnetic reconnection, and clarify how
waves are propagated, reflected, and dissipated. Phenomena indicative
of or byproducts of magnetic reconnection, such as flows and shocks,
are to be captured by SUVIT and by spectroscopic observations using
EUVS/LEMUR, while XIT observes rapid changes in temperature distribution
of plasma heated by shock waves.
Title: Association of Polar Faculae with the Polar Magnetic Patches
as Revealed by Hinode
Authors: Kaithakkal, A. J.; Tsuneta, S.; Suematsu, Y.; Kubo, M.;
Shiota, D.; Shimojo, M.
Bibcode: 2012AGUFMSH13C2273K
Altcode:
Polar faculae are small bright features in the polar region of the
Sun. They are observed with concentrations of magnetic fields. Previous
studies have shown that the number of polar faculae at latitudes greater
than 50 degrees has 11-year periodicity like the sunspot cycle, but
becomes a maximum in the solar minimum period. The aim of this study is
to understand the magnetic properties of faculae, which are believed
to be associated with the polar magnetic patches. We analysed data of
the north polar region taken by the Hinode/SOT spectropolarimeter (SP)
in September 2007. Accurate measurements of vector magnetic fields
at high spatial resolution by Hinode/SP for the first time allow us
to compare polar faculae with polar magnetic fields in detail. The
continuum intensity map is corrected for limb darkening. There are many
patchy magnetic field structures in the polar region and thresholds on
both size and intensity for the patches are applied to automatically
choose faculae. The definition of magnetic patch is same as in Shiota et
al. (2012 ApJ). We find that magnetic patches are not uniformly bright
but contain smaller faculae inside. The following results describe
the properties of faculae associated with the majority polarity
patches. Our results show that a positive correlation exists between
total flux and average intensity contrast of faculae. On average the
contribution of polar faculae to the total flux of the patch is less
than 30% and the area occupied by polar faculae with in a patch is
roughly 20-25%. We find that there are patches without faculae and
their number is much larger than those with faculae. We also find
that faculae are present in all the patches with total flux ≥ 10^19
Mx. Our result show that faculae are polarity independent and hence are
associated with minority polarity patches as well. But the flux of these
minority polarity faculae is <10^18 Mx in most of the cases. These
results suggest that the magnetic patches and polar faculae do not
have a one-to-one spatial correspondence and have fine structure, and
may raise a fundamental question on our current understanding on the
formation of the faculae. Shiota et al. (2012 ApJ) report that there
are two classes of magnetic patches: small (< 10^18 Mx) and large
(≥10^18 Mx) of which the large patches contribute to the cyclic
variation of the polar magnetic flux. This is consistent with the
concept of faculae as a proxy of the majority polarity magnetic flux.
Title: Chromospheric Lyman-alpha spectro-polarimeter (CLASP)
Authors: Kano, Ryouhei; Bando, Takamasa; Narukage, Noriyuki; Ishikawa,
Ryoko; Tsuneta, Saku; Katsukawa, Yukio; Kubo, Masahito; Ishikawa,
Shin-nosuke; Hara, Hirohisa; Shimizu, Toshifumi; Suematsu, Yoshinori;
Ichimoto, Kiyoshi; Sakao, Taro; Goto, Motoshi; Kato, Yoshiaki; Imada,
Shinsuke; Kobayashi, Ken; Holloway, Todd; Winebarger, Amy; Cirtain,
Jonathan; De Pontieu, Bart; Casini, Roberto; Trujillo Bueno, Javier;
Štepán, Jiří; Manso Sainz, Rafael; Belluzzi, Luca; Asensio Ramos,
Andres; Auchère, Frédéric; Carlsson, Mats
Bibcode: 2012SPIE.8443E..4FK
Altcode:
One of the biggest challenges in heliophysics is to decipher the
magnetic structure of the solar chromosphere. The importance of
measuring the chromospheric magnetic field is due to both the key role
the chromosphere plays in energizing and structuring the outer solar
atmosphere and the inability of extrapolation of photospheric fields to
adequately describe this key boundary region. Over the last few years,
significant progress has been made in the spectral line formation
of UV lines as well as the MHD modeling of the solar atmosphere. It
is found that the Hanle effect in the Lyman-alpha line (121.567 nm)
is a most promising diagnostic tool for weaker magnetic fields in
the chromosphere and transition region. Based on this groundbreaking
research, we propose the Chromospheric Lyman-Alpha Spectro-Polarimeter
(CLASP) to NASA as a sounding rocket experiment, for making the first
measurement of the linear polarization produced by scattering processes
and the Hanle effect in the Lyman-alpha line (121.567 nm), and making
the first exploration of the magnetic field in the upper chromosphere
and transition region of the Sun. The CLASP instrument consists
of a Cassegrain telescope, a rotating 1/2-wave plate, a dual-beam
spectrograph assembly with a grating working as a beam splitter, and
an identical pair of reflective polarization analyzers each equipped
with a CCD camera. We propose to launch CLASP in December 2014.
Title: Granular-Scale Magnetic Flux Cancellations in the Photosphere
Authors: Kubo, M.; Low, B. C.; Lites, B. W.
Bibcode: 2012ASPC..454...41K
Altcode:
We find the unresolved flux removal process at the polarity inversion
line formed by canceling opposite-polarity magnetic elements. Further
details and results of this work can be seen in Kubo et al. (2010).
Title: Role of small-scale magnetic elements in magnetic flux
transportation on the solar surface
Authors: Kubo, Masahito
Bibcode: 2012cosp...39..988K
Altcode: 2012cosp.meet..988K
The magnetic fields emerge into the solar surface from the convection
zone. Recent observations at high spatial resolution reveal ubiquitous
flux emergence at granular scale on the solar surface in the quiet
Sun. The emerged small-scale magnetic elements dynamically evolve with
granular convective flows, and form a network magnetic field along the
boundaries of supergranular cells. Such a magneto-convection in the
photosphere is an energy source for heating and dynamics in the upper
atmospheres. The small-scale magnetic elements are also important for
the flux transportation in active regions. We quantify the evolution
of sunspot magnetic flux by using continuous vector magnetic field
measurements under seeing free condition. The magnetic flux budget
of the decaying sunspot reveals that small-scale magnetic elements
called moving magnetic features carry away enough magnetic flux from
the sunspot through the moat region. The transported magnetic flux is
mostly removed from the photosphere by ``magnetic flux cancellation''
that is the mutual loss of magnetic flux due to the apparent collision
of opposite-polarity magnetic elements. The granular-scale flux
cancellation can be seen everywhere on the solar surface, and the flux
cancellation is essential to understand the dissipation of magnetic
flux from the solar surface. We find unresolved, small-scale flux
cancellations along the polarity inversion line that is formed between
granular-scale opposite polarity magnetic elements. Highly asymmetric
Stokes-V profiles are observed along the polarity inversion line. Such
asymmetric profiles can be made by the sum of the Stokes-V profiles at
the opposite-polarity magnetic elements next to the polarity inversion
line. This means that the approaching bipolar magnetic elements still
keep their nature within the pixel where they come in contact with
each other. It is suggested that the unresolved flux removal process
in the photosphere or in the lower chromosphere.
Title: The Chromospheric Lyman-Alpha SpectroPolarimeter: CLASP
Authors: Kobayashi, K.; Kano, R.; Trujillo-Bueno, J.; Asensio Ramos,
A.; Bando, T.; Belluzzi, L.; Carlsson, M.; De Pontieu, R. C. B.; Hara,
H.; Ichimoto, K.; Ishikawa, R.; Katsukawa, Y.; Kubo, M.; Manso Sainz,
R.; Narukage, N.; Sakao, T.; Stepan, J.; Suematsu, Y.; Tsuneta, S.;
Watanabe, H.; Winebarger, A.
Bibcode: 2012ASPC..456..233K
Altcode:
The magnetic field plays a crucial role in the chromosphere and the
transition region, and our poor empirical knowledge of the magnetic
field in the upper chromosphere and transition region is a major
impediment to advancing the understanding of the solar atmosphere. The
Hanle effect promises to be a valuable alternative to Zeeman effect
as a method of measuring the magnetic field in the chromosphere and
transition region; it is sensitive to weaker magnetic fields, and
also sensitive to tangled, unresolved field structures. CLASP
is a sounding rocket experiment that aims to observe the Hanle effect
polarization of the Lyman α (1215.67Å) line in the solar chromosphere
and transition region, and prove the usefulness of this technique in
placing constraints on the magnetic field strength and orientation
in the low plasma-β region of the solar atmosphere. The Ly-α line
has been chosen because it is a chromospheric/transition-region line,
and because the Hanle effect polarization of this line is predicted to
be sensitive to 10-250 Gauss, encompassing the range of interest. The
CLASP instrument is designed to measure linear polarization in the
Ly-α line with a polarization sensitivity of 0.1%. The instrument is
currently funded for development. The optical design of the instrument
has been finalized, and an extensive series of component-level tests
are underway to validate the design.
Title: Diffusion and Decay of Sunspots
Authors: Kubo, M.
Bibcode: 2012ASPC..455...49K
Altcode:
Sunspots are the most prominent magnetic structures on the solar
surface. The evolution of sunspots is a long-standing question in
the solar magnetism. A study of the decay of sunspots as well as
the formation is necessary to understand the evolutionary history of
sunspots. This paper is a short review on new insights into diffusion
and decay of sunspots obtained from Hinode observations.
Title: Ly-alpha polarimeter design for CLASP rocket experiment
Authors: Kubo, M.; Watanabe, H.; Narukage, N.; Ishikawa, R.; Bando,
T.; Kano, R.; Tsuneta, S.; Kobayashi, K.; Ichimoto, K.; Trujillo Bueno,
J.; Song, D.
Bibcode: 2011AGUFM.P11F1627K
Altcode:
A sounding-rocket program called the Chromospheric Lyman-Alpha
Spectro-Polarimeter (CLASP) is proposed to be launched in the Summer
of 2014. CLASP will observe the upper solar chromosphere in Ly-alpha
(121.567 nm), aiming to detect the linear polarization signal produced
by scattering processes and the Hanle effect for the first time. The
CLASP needs a rotating half-waveplate and a polarization analyzer
working at the Ly-alpha wavelength to measure the linear polarization
signal. We select Magnesium Fluoride (MgF2) as a material of the
optical components because of its birefringent property and high
transparency at UV wavelength. We have confirmed that the reflection
at the Brewster's Angle of MgF2 plate is a good polarization analyzer
for the Ly-alpha line by deriving its ordinary refractive index and
extinction coefficient along the ordinary and extraordinary axes. These
optical parameters are calculated with a least-square fitting in such a
way that the reflectance and transmittance satisfy the Kramers-Kronig
relation. The reflectance and transmittance against oblique incident
angles for the s-polarized and the p-polarized light are measured
using the synchrotron beamline at the Ultraviolet Synchrotron Orbital
Radiation Facility (UVSOR). We have also measured a retardation of
a zeroth-order waveplate made of MgF2. The thickness difference of
the waveplate is 14.57 um.This waveplate works as a half-waveplate at
121.74 nm. From this measurement, we estimate that a waveplate with
the thickness difference of 15.71 um will work as a half-waveplate
at the Ly-alpha wavelength. We have developed a rotating waveplate -
polarization analyzer system called a prototype of CLASP polarimeter,
and input the perfect Stokes Q and U signals. The modulation patterns
that are consistent with the theoretical prediction are successfully
obtained in both cases.
Title: The Chromospheric Lyman-Alpha SpectroPolarimeter (CLASP)j
Authors: Kobayashi, K.; Tsuneta, S.; Trujillo Bueno, J.; Bando, T.;
Belluzzi, L.; Casini, R.; Carlsson, M.; Cirtain, J. W.; De Pontieu,
B.; Hara, H.; Ichimoto, K.; Ishikawa, R.; Kano, R.; Katsukawa, Y.;
Kim, T.; Kubo, M.; Manso Sainz, R.; Narukage, N.; Asensio Ramos,
A.; Robinson, B.; Sakao, T.; Shimizu, T.; Stepan, J.; Suematsu, Y.;
Watanabe, H.; West, E.; Winebarger, A. R.
Bibcode: 2011AGUFM.P14C..05K
Altcode:
We present an overview of the Chromospheric Lyman-Alpha
SpectroPolarimeter (CLASP) program. CLASP is a proposed sounding rocket
experiment currently under development as collaboration between Japan,
USA and Spain. The aim is to achieve the first measurement of magnetic
field in the upper chromosphere and transition region of the Sun
through the detection and measurement of Hanle effect polarization
of the Lyman alpha line. The Hanle effect (i.e. the magnetic field
induced modification of the linear polarization due to scattering
processes in spectral lines) is believed to be a powerful tool for
measuring the magnetic field in the upper chromosphere, as it is more
sensitive to weaker magnetic fields than the Zeeman effect, and also
sensitive to magnetic fields tangled at spatial scales too small to be
resolved. The Lyman-alpha (121.567 nm) line has been chosen because
it is a chromospheric/transition-region line, and because the Hanle
effect polarization of the Lyman-alpha line is predicted to be sensitive
to 10-250 Gauss, encompassing the range of interest. Hanle effect is
predicted to be observable as linear polarization or depolarization,
depending on the geometry, with a fractional polarization amplitude
varying between 0.1% and 1% depending on the strength and orientation of
the magnetic field. This quantification of the chromospheric magnetic
field requires a highly sensitive polarization measurement. The
CLASP instrument consists of a large aperture (287 mm) Cassegrain
telescope mated to a polarizing beamsplitter and a matched pair
of grating spectrographs. The polarizing beamsplitter consists
of a continuously rotating waveplate and a linear beamsplitter,
allowing simultaneous measurement of orthogonal polarizations and
in-flight self-calibration. Development of the instrument is underway,
and prototypes of all optical components have been tested using a
synchrotron beamline. The experiment is proposed for flight in 2014.
Title: Ly-alpha polarimeter design for CLASP rocket experiment
Authors: Watanabe, H.; Narukage, N.; Kubo, M.; Ishikawa, R.; Bando, T.;
Kano, R.; Tsuneta, S.; Kobayashi, K.; Ichimoto, K.; Trujillo-Bueno, J.
Bibcode: 2011SPIE.8148E..0TW
Altcode: 2011SPIE.8148E..25W; 2014arXiv1407.4577W
A sounding-rocket program called the Chromospheric Lyman-Alpha
Spectro-Polarimeter (CLASP) is proposed to be launched in the summer of
2014. CLASP will observe the solar chromosphere in Ly-alpha (121.567
nm), aiming to detect the linear polarization signal produced by
scattering processes and the Hanle effect for the first time. The
polarimeter of CLASP consists of a rotating half-waveplate, a beam
splitter, and a polarization analyzer. Magnesium Fluoride (MgF2) is
used for these optical components, because MgF2 exhibits birefringent
property and high transparency at ultraviolet wavelength. The
development and comprehensive testing program of the optical components
of the polarimeter is underway using the synchrotron beamline at the
Ultraviolet Synchrotron Orbital Radiation Facility (UVSOR). The first
objective is deriving the optical constants of MgF2 by the measurement
of the reflectance and transmittance against oblique incident angles
for the s-polarized and the p-polarized light. The ordinary refractive
index and extinction coefficient along the ordinary and extraordinary
axes are derived with a least-square fitting in such a way that the
reflectance and transmittance satisfy the Kramers-Krönig relation. The
reflection at the Brewster's Angle of MgF2 plate is confirmed to become
a good polarization analyzer at Ly-alpha. The second objective is the
retardation measurement of a zeroth-order waveplate made of MgF2. The
retardation of a waveplate is determined by observing the modulation
amplitude that comes out of a waveplate and a polarization analyzer. We
tested a waveplate with the thickness difference of 14.57 um. The 14.57
um waveplate worked as a half-waveplate at 121.74 nm. We derived that
a waveplate with the thickness difference of 15.71 um will work as a
half-waveplate at Ly-alpha wavelength. We developed a prototype of CLASP
polarimeter using the MgF2 half-waveplate and polarization analyzers,
and succeeded in obtaining the modulation patterns that are consistent
with the theoretical prediction. We confirm that the performance of
the prototype is optimized for measuring linear polarization signal
with the least effect of the crosstalk from the circular polarization.
Title: VFISV: Very Fast Inversion of the Stokes Vector for the
Helioseismic and Magnetic Imager
Authors: Borrero, J. M.; Tomczyk, S.; Kubo, M.; Socas-Navarro, H.;
Schou, J.; Couvidat, S.; Bogart, R.
Bibcode: 2011SoPh..273..267B
Altcode: 2009arXiv0901.2702B
In this paper we describe in detail the implementation and main
properties of a new inversion code for the polarized radiative transfer
equation (VFISV: Very Fast Inversion of the Stokes Vector). VFISV will
routinely analyze pipeline data from the Helioseismic and Magnetic
Imager (HMI) on-board of the Solar Dynamics Observatory (SDO). It
will provide full-disk maps (4096×4096 pixels) of the magnetic field
vector on the Solar Photosphere every ten minutes. For this reason
VFISV is optimized to achieve an inversion speed that will allow
it to invert sixteen million pixels every ten minutes with a modest
number (approx. 50) of CPUs. Here we focus on describing a number of
important details, simplifications and tweaks that have allowed us to
significantly speed up the inversion process. We also give details on
tests performed with data from the spectropolarimeter on-board of the
Hinode spacecraft.
Title: Overview of Chromospheric Lyman-Alpha SpectroPolarimeter
(CLASP)
Authors: Narukage, Noriyuki; Tsuneta, Saku; Bando, Takamasa; Kano,
Ryouhei; Kubo, Masahito; Ishikawa, Ryoko; Hara, Hirohisa; Suematsu,
Yoshinori; Katsukawa, Yukio; Watanabe, Hiroko; Ichimoto, Kiyoshi;
Sakao, Taro; Shimizu, Toshifumi; Kobayashi, Ken; Robinson, Brian; Kim,
Tony; Winebarger, Amy; West, Edward; Cirtain, Jonathan; De Pontieu,
Bart; Casini, Roberto; Trujillo Bueno, Javier; Stepan, Jiri; Manso
Sainz, Rafael; Belluzzi, Luca; Asensio Ramos, Andres; Carlsson, Mats
Bibcode: 2011SPIE.8148E..0HN
Altcode: 2011SPIE.8148E..16N
The solar chromosphere is an important boundary, through which all of
the plasma, magnetic fields and energy in the corona and solar wind
are supplied. Since the Zeeman splitting is typically smaller than
the Doppler line broadening in the chromosphere and transition region,
it is not effective to explore weak magnetic fields. However, this is
not the case for the Hanle effect, when we have an instrument with
high polarization sensitivity (~ 0.1%). "Chromospheric Lyman- Alpha
SpectroPolarimeter (CLASP)" is the sounding rocket experiment to detect
linear polarization produced by the Hanle effect in Lyman-alpha line
(121.567 nm) and to make the first direct measurement of magnetic
fields in the upper chromosphere and lower transition region. To
achieve the high sensitivity of ~ 0.1% within a rocket flight (5
minutes) in Lyman-alpha line, which is easily absorbed by materials,
we design the optical system mainly with reflections. The CLASP
consists of a classical Cassegrain telescope, a polarimeter and a
spectrometer. The polarimeter consists of a rotating 1/2-wave plate
and two reflecting polarization analyzers. One of the analyzer also
works as a polarization beam splitter to give us two orthogonal linear
polarizations simultaneously. The CLASP is planned to be launched in
2014 summer.
Title: Temporal Relation Between the Disappearance of Penumbral
Fine-scale Structure and Evershed Flow
Authors: Kubo, M.; Ichimoto, K.; Lites, B. W.; Shine, R. A.
Bibcode: 2011ApJ...731...84K
Altcode: 2011arXiv1102.1137K
We investigate the temporal relation between the Evershed flow,
dot-like bright features (penumbral grain), the complex magnetic
field structure, and dark lanes (dark core) along bright filaments in
a sunspot penumbra. We use a time series of high spatial resolution
photospheric intensity, vector magnetic field maps, and Doppler velocity
maps obtained with the Solar Optical Telescope aboard the Hinode
spacecraft. We conclude that the appearance and disappearance of the
Evershed flow and penumbra grains occur at nearly the same time and are
associated with changes of the inclination angle of the magnetic field
from vertical to more horizontal. This supports the idea that Evershed
flow is a result of thermal convection in the inclined field lines. The
dark core of the bright penumbral filament also appears coincidental
with the Evershed flow. However, the dark-cored bright filament
survives at least for 10-20 minutes after the disappearance of the
Evershed flow. The heat input into the bright filament continues even
after the end of heat transfer by the Evershed flow. This suggests that
local heating along the bright filament is important for maintaining
its brightness, in addition to heat transfer by the Evershed flow.
Title: Emergence of Helical Flux and the Formation of an Active
Region Filament Channel
Authors: Lites, B. W.; Kubo, M.; Berger, T.; Frank, Z.; Shine, R.;
Tarbell, T.; Title, A.; Okamoto, T. J.; Otsuji, K.
Bibcode: 2010ApJ...718..474L
Altcode:
We present comprehensive observations of the formation and evolution
of a filament channel within NOAA Active Region (AR) 10978 from
Hinode/Solar Optical Telescope and TRACE. We employ sequences
of Hinode spectro-polarimeter maps of the AR, accompanying Hinode
Narrowband Filter Instrument magnetograms in the Na I D1 line, Hinode
Broadband Filter Instrument filtergrams in the Ca II H line and G-band,
Hinode X-ray telescope X-ray images, and TRACE Fe IX 171 Å image
sequences. The development of the channel resembles qualitatively
that presented by Okamoto et al. in that many indicators point to
the emergence of a pre-existing sub-surface magnetic flux rope. The
consolidation of the filament channel into a coherent structure takes
place rapidly during the course of a few hours, and the filament form
then gradually shrinks in width over the following two days. Particular
to this filament channel is the observation of a segment along its
length of horizontal, weak (500 G) flux that, unlike the rest of the
filament channel, is not immediately flanked by strong vertical plage
fields of opposite polarity on each side of the filament. Because this
isolated horizontal field is observed in photospheric lines, we infer
that it is unlikely that the channel formed as a result of reconnection
in the corona, but the low values of inferred magnetic fill fraction
along the entire length of the filament channel suggest that the bulk
of the field resides somewhat above the low photosphere. Correlation
tracking of granulation in the G band presents no evidence for either
systematic flows toward the channel or systematic shear flows along
it. The absence of these flows, along with other indications of these
data from multiple sources, reinforces (but does not conclusively
demonstrate) the picture of an emerging flux rope as the origin of
this AR filament channel.
Title: Granular-scale Magnetic Flux Cancellations in the Photosphere
Authors: Kubo, M.; Low, B. C.; Lites, B. W.
Bibcode: 2010ApJ...712.1321K
Altcode: 2010arXiv1003.2863K
We investigate the evolution of five granular-scale magnetic flux
cancellations just outside the moat region of a sunspot by using
accurate spectropolarimetric measurements and G-band images with the
Solar Optical Telescope (SOT) aboard Hinode. The opposite-polarity
magnetic elements approach a junction of the intergranular lanes and
then collide with each other there. The intergranular junction has
strong redshifts, darker intensities than the regular intergranular
lanes, and surface converging flows. This clearly confirms that
the converging and downward convective motions are essential for the
approaching process of the opposite-polarity magnetic elements. However,
the motion of the approaching magnetic elements does not always match
with their surrounding surface flow patterns in our observations. This
suggests that, in addition to the surface flows, subsurface downward
convective motions and subsurface magnetic connectivities are important
for understanding the approach and collision of the opposite-polarity
elements observed in the photosphere. We find that the horizontal
magnetic field appears between the canceling opposite-polarity
elements in only one event. The horizontal fields are observed along
the intergranular lanes with Doppler redshifts. This cancellation is
most probably a result of the submergence (retraction) of low-lying
photospheric magnetic flux. In the other four events, the horizontal
field is not observed between the opposite-polarity elements at any time
when they approach and cancel each other. These approaching magnetic
elements are more concentrated rather than gradually diffused, and
they have nearly vertical fields even while they are in contact each
other. We thus infer that the actual flux cancellations are highly
time-dependent events at scales less than a pixel of Hinode SOT (about
200 km) near the solar surface.
Title: Astrobiology Student Intern Program at Lassen Volcanic
National Park
Authors: Dueck, S. L.; Zachary, S.; Michael, D.; Parenteau, M.; Kubo,
M.; Jahnke, L. L.; Scalice, D.; Des Marais, D. J.
Bibcode: 2010LPICo1538.5434D
Altcode:
The NASA Astrobiology Institute (NAI) Ames Team has partnered with
Lassen Volcanic National Park and Red Bluff High School to engage
high school students in the collection of scientific data for NASA
astrobiologists and the National Park Service.
Title: Granular scale magnetic flux cancellations .
Authors: Kubo, M.; Low, B. C.; Lites, B. W.
Bibcode: 2010MmSAI..81..790K
Altcode:
We summarize the evolution of granular-scale ``magnetic-flux
cancellation'' as observed with Hinode/SOT. Further details and results
of this work are given in \citet{Kubo2009}.
Title: Unresolved Magnetic Flux Removal Process in the Photosphere
Authors: Kubo, Masahito; Chye Low, Boon; Lites, Bruce
Bibcode: 2010cosp...38.2828K
Altcode: 2010cosp.meet.2828K
The mutual loss of magnetic flux due to the apparent collision
of opposite-polarity magnetic elements is called "magnetic flux
cancellation" as a descriptive term. The flux cancellation is
essential to understand the dissipation of magnetic flux from the
solar surface. An Ω-loop submerging below the surface or a U-loop
rising through the photosphere is the usual idea to explain the
magnetic flux cancellation. Magnetic reconnection may be crucial for
the forma-tion of these loops, especially for the submerging -loop. In
fact, chromospheric and coronal activities are often observed at the
cancellation sites. We investigate the evolution of 5 cancel-lation
events of the opposite-polarity magnetic elements at granular scales by
using accurate spectropolarimetric measurements with the Solar Optical
Telescope aboard Hinode. We find that the horizontal magnetic field,
which is expected in both submerging Ω-loop model and emerging U-loop
model, does not appear between the canceling magnetic elements in 4
of the 5 events. The approaching magnetic elements in these events are
more concentrated rather than gradually diffused, and they have nearly
vertical fields even while they are in contact each other. We thus imply
that the actual flux cancellation is highly time dependent event near
the solar surface at scales less than a pixel of Hinode/SOT (about 200
km). At the polarity inversion line formed by the canceling magnetic
elements, highly asymmetric Stokes-V profiles are observed. We confirm
that such asymmetric profile can be made by the sum of the profiles at
the opposite-polarity magnetic elements next to the polarity inversion
line. This means that the approaching bipolar flux tubes still keep
their nature within the pixel where they come in contact with each
other, and thus supports the unresolved flux removal process within
the pixel at the polarity inversion line.
Title: Magnetic Flux Budget in a Decaying Active Region
Authors: Kubo, M.; Lites, B. W.; Shimizu, T.; Ichimoto, K.
Bibcode: 2009ASPC..415..359K
Altcode:
We investigate the sunspot decay process in terms of the magnetic flux
budget of a decaying sunspot. This article is based on results in Kubo
et al. 2008. Please see this paper for further details.
Title: Mineralogy and Organic Geochemistry of Acid Sulfate
Environments from Valles Caldera, New Mexico: Habitability, Weathering
and Biosignatures
Authors: Vogel, M. B.; Des Marais, D. J.; Jahnke, L. L.; Kubo, M.
Bibcode: 2009AGUFM.P43C1449V
Altcode:
We report on the mineralogy, organic preservation potential and
habitability of sulfate deposits in acid sulfate volcanic settings at
Valles Caldera, New Mexico. Fumaroles and acidic springs are potential
analogs for aqueous environments on Mars and may offer insights
into habitability of sulfate deposits such as those at Meridiani
Planum. Sulfates recently detected on Mars are posited to have formed
from fluids derived from basaltic weathering and igneous volatile input,
ultimately precipitating from acidic brines subjected to desiccation
and freeze-thaw cycles (McClennan and Grotzinger, 2008). Key issues
concerning martian sulfate deposits are their relationship to aqueous
clay deposits, and whether or not specific sulfates deposits represent
former habitable environments (see Soderblum and Bell, 2008; Tosca
et al., 2008). Modern terrestrial volcanic fumaroles and hot springs
precipitate various Ca-, Mg- and Fe- sulfates along with clays, and
can help clarify whether certain acid sulfate mineral assemblages
reflect habitable environments. Valles caldera is a resurgent caldera
last active in the Pleistocene (1.4 - 1.0 Ma) that hosts several
active fumaroles and over 40 geothermal exploration wells (see Goff,
2009). Fumaroles and associated mudpots and springs at Valles range from
pH < 1 to 3, and affect argillic alteration upon rhylolitic tuffs and
sedimentary deposits (Charles et al., 1986). We identified assemblages
containing gypsum, quartz, Al-sulfates, elemental sulfur, clays and
other minerals using XRD and SEM-EDS. Our previous research has shown
that sulfates from different marine depositional environments display
textural and morphological traits that are indicative of biological
influence, or specific conditions in the depositional environments
(Vogel et al., 2009). Gypsum crystals that develop in the presence of
microbial biofilms in marine environments may have distorted crystal
morphologies, biofilm - associated dissolution features, and accessory
carbonate minerals. Gypsum from Valles Caldera fumaroles develops in the
absence of microbial biofilms and differs from biologically influenced
marine gypsum in terms of is highly prismatic morphology, lack of
texture, and association with clays, and other sulfates. Studies of
Valles gypsum crystals therefore support the uniqueness of the putative
morphological biosignatures in marine gypsum. We also assayed organic
matter from fumarole encrustations to understand how low pH and sulfate
content may discriminate against or enhance preservation of specific
classes of organic compounds in acid sulfate environments. Similar
to gypsiferous marine environments, organics are characterized by
abundant organosulfur complexes. Long chain alkanes (> nC22) are
abundant from acid sulfate environments. As with hypersaline marine
depositional environments, sulfidation appears to be a major diagenetic
pathway for organic matter in acid sulfate environments.
Title: Granular Scale Magnetic Flux Cancellations as Observed with
the Hinode/SOT
Authors: Kubo, M.; Low, B.; Lites, B. W.
Bibcode: 2009AGUFMSH53B..05K
Altcode:
The mutual loss of magnetic flux due to the apparent collision
of opposite-polarity magnetic elements is called ``magnetic flux
cancellation'' as a descriptive term. The flux cancellation is
essential to understand the dissipation of magnetic flux from the
solar surface. We investigate the evolution of 5 granular-scale flux
cancellations just outside the moat region of a sunspot by using
accurate spectropolarimetric measurements with the Solar Optical
Telescope aboard Hinode. We find that the opposite-polarity magnetic
elements approach a junction of the intergranular lanes and then they
collide with each other there. The intergranular junction has Doppler
red shifts, darker intensities than the regular intergranular lanes,
and surface converging flows. We also find that the horizontal magnetic
field appears between the canceling elements in only one event. The
horizontal fields are observed along the intergranular lanes with red
shifts. This cancellation is most probably a result of the submergence
of low-lying photospheric magnetic flux. In the other 4 events, the
horizontal field is not observed between the opposite-polarity magnetic
elements at any time when they approach and cancel each other. These
canceling elements have nearly vertical fields even while they are
in contact each other. These events are more interesting because
in the usual idea of the submergence of a low lying Ω-loop or the
buoyant rise of a U-loop, the appearance of a horizontal field is the
observational signature of the loop top (or bottom) passing across
the photosphere. Our observational results suggest the possibility
that the actual flux cancellation is highly time dependent events near
the solar surface at scales less than a pixel of Hinode/SOT (about 200
km). Observations with a spatial resolution higher than Hinode/SOT are
essential to reveal physical process of the dissipation of magnetic
flux on the Sun.
Title: Magnetic Flux Budget of a Decaying Sunspot
Authors: Kubo, Masahito; Lites, Bruce W.; Shimizu, Toshifumi;
Ichimoto, Kiyoshi
Bibcode: 2009shin.confE...9K
Altcode:
Numerous small magnetic elements called moving magnetic features (MMFs)
are generally observed in the moat region that surrounds a sunspot. We
attempt to address a basic question how much magnetic flux is carried
away from a sunspot by MMFs and is subsequently removed from the
photosphere. This is essential for understanding decay of sunspots
and distribution of magnetic flux on the Sun. We estimate the magnetic
flux budget in a decaying sunspot and its surrounding moat region by
using a time series of the spatial distribution of vector magnetic
fields in the photosphere. Spectropolarimetric measurements with the
Solar Optical Telescope aboard the Hinode satellite allow us, for
the first time, to know an accurate flux change without any effects
of atmospheric seeing. The amount of magnetic flux that decreases
in the sunspot and (inner) moat region is very similar to magnetic
flux transported to the outer boundary of the moat region. The flux
loss rates of magnetic elements with positive and negative polarities
balance each other around the outer boundary of the moat region. These
results suggest that most of the magnetic flux in the sunspot is
transported to the outer boundary of the moat region as MMFs, and
then the transported flux is removed from the photosphere by apparent
collisions of opposite-polarity magnetic elements (called
Title: A New View of Fine Scale Dynamics and Magnetism of Sunspots
Revealed by Hinode/SOT
Authors: Ichimoto, K.; Suematsu, Y.; Katsukawa, Y.; Tsuneta, S.;
Shimojo, M.; Shimizu, T.; Shine, R. A.; Tarbell, T. D.; Berger, T.;
Title, A. M.; Lites, B. W.; Kubo, M.; Yokoyama, T.; Nagata, S.
Bibcode: 2009ASPC..405..167I
Altcode:
The Solar Optical Telescope on-board Hinode is providing a new view of
the fine scale dynamics in sunspots with its high spatial resolution and
unprecedented image stability. We present three features related to the
Evershed flow each of which raises a new puzzle in sunspot dynamics;
i.e., twisting appearance of penumbral filaments, the source and sink
of individual Evershed flow channels, and the net circular polarization
in penumbrae with its spatial relation to the Evershed flow channels.
Title: Has Hinode Revealed the Missing Turbulent Flux of the
Quiet Sun?
Authors: Lites, B. W.; Kubo, M.; Socas-Navarro, H.; Berger, T.; Frank,
Z.; Shine, R.; Tarbell, T.; Title, A. M.; Ichimoto, K.; Katsukawa,
Y.; Tsuneta, S.; Suematsu, Y.; Shimizu, T.; Nagata, S.
Bibcode: 2009ASPC..405..173L
Altcode:
The Hinode Spectro-Polarimeter has revealed the presence of surprisingly
strong horizontal magnetic fields nearly everywhere in the quiet
solar atmosphere. These horizontal fields, along with measures of the
vertical fields, may be the signature of the ``hidden turbulent flux''
of the quiet Sun. The measured horizontal fields average at least to
55 Gauss: nearly 5 times that of the measured longitudinal apparent
flux density. The nature of these fields are reviewed, and discussed
in the light of recent magneto-convection numerical simulations of
the quiet Sun.
Title: Hinode Observation of the Magnetic Fields in a Sunspot Light
Bridge Accompanied by Long-Lasting Chromospheric Plasma Ejections
Authors: Shimizu, Toshifumi; Katsukawa, Yukio; Kubo, Masahito; Lites,
Bruce W.; Ichimoto, Kiyoshi; Suematsu, Yoshinori; Tsuneta, Saku;
Nagata, Shin'ichi; Shine, Richard A.; Tarbell, Theodore D.
Bibcode: 2009ApJ...696L..66S
Altcode:
We present high-resolution magnetic field measurements of a sunspot
light bridge (LB) that produced chromospheric plasma ejections
intermittently and recurrently for more than 1 day. The observations
were carried out with the Hinode Solar Optical Telescope on 2007
April 29 and 30. The spectro-polarimeter reveals obliquely oriented
magnetic fields with vertical electric current density higher than
100 mA m-2 along the LB. The observations suggest that
current-carrying highly twisted magnetic flux tubes are trapped below
a cusp-shaped magnetic structure along the LB. The presence of trapped
current-carrying flux tubes is essential for causing long-lasting
chromospheric plasma ejections at the interface with pre-existing
vertically oriented umbral fields. A bidirectional jet was clearly
detected, suggesting magnetic reconnections occurring at very low
altitudes, slightly above the height where the vector magnetic fields
are measured. Moreover, we found another strong vertical electric
current on the interface between the current-carrying flux tube
and pre-existing umbral field, which might be a direct detection
of the currents flowing in the current sheet formed at the magnetic
reconnection sites.
Title: Magnetic Flux Budget of a Decaying Sunspot
Authors: Kubo, Masahito; Lites, B. W.; Shimizu, T.; Ichimoto, K.
Bibcode: 2009SPD....40.0905K
Altcode:
We estimate how much magnetic flux is lost in a decaying sunspot
and how much magnetic flux is carried away from the sunspot through
its surrounding moat region. A time series of spectropolarimetric
measurements with the Solar Optical Telescope aboard Hinode allows us,
for the first time, to investigate an accurate flux change without
any effects of atmospheric seeing. The amount of magnetic flux that
decreases in the sunspot and moat region is almost equal to that of
magnetic flux transported to the outer boundary of the moat region. The
flux loss rates of magnetic elements with positive and negative
polarities are balanced each other around the outer boundary of the
moat region. These results suggest that most of the magnetic flux in
the sunspot is transported to the outer boundary of the moat region
as moving magnetic features, and then removed from the photosphere by
flux cancellation around the moat boundary.
Title: Multiwavelength Observation of Electron Acceleration in the
2006 December 13 Flare
Authors: Minoshima, T.; Imada, S.; Morimoto, T.; Kawate, T.;
Koshiishi, H.; Kubo, M.; Inoue, S.; Isobe, H.; Masuda, S.; Krucker,
S.; Yokoyama, T.
Bibcode: 2009ApJ...697..843M
Altcode: 2009arXiv0903.1144M
We present a multiwavelength observation of a solar flare occurring on
2006 December 13 with Hinode, RHESSI, and the Nobeyama Radio Observatory
to study the electron acceleration site and mechanism. The Solar Optical
Telescope (SOT) on board Hinode observed elongated flare ribbons, and
RHESSI observed double-footpoint hard X-ray (HXR) sources appearing
in part of the ribbons. A photospheric vector magnetogram obtained
from SOT reveals that the HXR sources are located at the region where
horizontal magnetic fields change direction. The region is interpreted
as the footpoint of magnetic separatrix. Microwave images taken
with the Nobeyama Radioheliograph show a loop structure connecting
the HXR sources. The brighter parts of the microwave intensity are
located between the top and footpoints of the loop. We consider these
observations as evidence of electron acceleration near the magnetic
separatrix and injection parallel to the field line.
Title: Prominence Formation Associated with an Emerging Helical
Flux Rope
Authors: Okamoto, Takenori J.; Tsuneta, Saku; Lites, Bruce W.; Kubo,
Masahito; Yokoyama, Takaaki; Berger, Thomas E.; Ichimoto, Kiyoshi;
Katsukawa, Yukio; Nagata, Shin'ichi; Shibata, Kazunari; Shimizu,
Toshifumi; Shine, Richard A.; Suematsu, Yoshinori; Tarbell, Theodore
D.; Title, Alan M.
Bibcode: 2009ApJ...697..913O
Altcode: 2009arXiv0904.0007O
The formation and evolution process and magnetic configuration of
solar prominences remain unclear. In order to study the formation
process of prominences, we examine continuous observations of a
prominence in NOAA AR 10953 with the Solar Optical Telescope on
the Hinode satellite. As reported in our previous Letter, we find
a signature suggesting that a helical flux rope emerges from below
the photosphere under a pre-existing prominence. Here we investigate
more detailed properties and photospheric indications of the emerging
helical flux rope, and discuss their relationship to the formation of
the prominence. Our main conclusions are: (1) a dark region with absence
of strong vertical magnetic fields broadens and then narrows in Ca II
H-line filtergrams. This phenomenon is consistent with the emergence
of the helical flux rope as photospheric counterparts. The size of the
flux rope is roughly 30,000 km long and 10,000 km wide. The width is
larger than that of the prominence. (2) No shear motion or converging
flows are detected, but we find diverging flows such as mesogranules
along the polarity inversion line. The presence of mesogranules may
be related to the emergence of the helical flux rope. (3) The emerging
helical flux rope reconnects with magnetic fields of the pre-existing
prominence to stabilize the prominence for the next several days. We
thus conjecture that prominence coronal magnetic fields emerge in
the form of helical flux ropes that contribute to the formation and
maintenance of the prominence.
Title: Observational Study of Particle Acceleration in the 2006
December 13 Flare
Authors: Minoshima, T.; Morimoto, T.; Kawate, T.; Imada, S.;
Koshiishi, H.; Masuda, S.; Kubo, M.; Inoue, S.; Isobe, H.; Krucker,
S.; Yokoyama, T.
Bibcode: 2008AGUFMSH41B1619M
Altcode:
We study the particle acceleration in a flare on 2006 December 13,
by using the Hinode, RHESSI, Nobeyama Radio Polarimeters (NoRP) and
Nobeyama Radioheliograph (NoRH) observations. For technical reasons,
both RHESSI and NoRH have a problem in imaging in this flare. Since we
have succeeded in solving the problem, it is now possible to discuss
the particle acceleration mechanism from an image analysis. This flare
shows very long-lasting (1 hour) non-thermal emissions, consisting of
many spikes. We focus on the second major spike at 02:29 UT, because
the RHESSI image is available only in this period. The RHESSI 35-100 keV
HXR image shows double sources located at the footpoints of the western
soft X-ray (SXR) loop seen by the Hinode/XRT. The non-linear force-free
(NLFF) modeling based on a magnetogram data by Inoue et al. shows the
NLFF to potential magnetic transition of the loop, which would induce
the electric field and then accelerate particles. Overlaying the HXR
image on the photospheric three-dimensional magnetic field map taken
by the Hinode Spectro-Polarimeter, we find that the HXR sources are
located at the region where the horizontal magnetic fields invert. The
NoRH 34 GHz microwave images show the loop structure connecting the
HXR sources. The microwave peaks do not located at the top of the
loop but between the loop top and the footpoints. The NoRP microwave
spectrum shows the soft-hard-soft pattern in the period, same as the
HXR spectrum (Ning 2008). From these observational results we suggest
that the electrons were accelerated parallel to the magnetic field
line near the magnetic separatrix.
Title: Erratum: "Magnetic Flux Loss and Flux Transport in a Decaying
Active Region" (ApJ, 686, 1447 [2008])
Authors: Kubo, M.; Lites, B. W.; Shimizu, T.; Ichimoto, K.
Bibcode: 2008ApJ...689.1456K
Altcode:
No abstract at ADS
Title: Study of Magnetic Channel Structure in Active Region 10930
Authors: Wang, Haimin; Jing, Ju; Tan, Changyi; Wiegelmann, Thomas;
Kubo, Masahito
Bibcode: 2008ApJ...687..658W
Altcode:
The concept of "magnetic channel" was first introduced by Zirin
& Wang. They were defined as a series of oppositely directed
vertical-field inversions separated by extremely narrow elongated
transverse fields. In this paper, we utilized unprecedented filtergraph
and spectropolarimetry observations from Hinode, and studied the
evolution and physical properties of channel structure of AR 10930
in detail. We found the following: (1) Channels are associated with
new flux emergence in the middle of existing penumbra connecting
the δ sunspot. (2) The width of each channel is in the order of 1''
or less. (3) The line-of-sight magnetic gradient is highest in the
channel, 2.4-4.9 G km-1. (4) The fields are highly sheared
and inclined with a median shear angle around 64° and inclination angle
around 25°. (5) Using nonlinear force-free field (NLFF) extrapolation,
we derive a near surface current system carrying electric current
in the order of 5 × 1011 A. (6) The X3.4 flare on 2006
December 13 occurred during the period that the channels rapidly
formed, but a few hours before the maximum phase of channel structure
development. Based on the observational evidence, we propose that the
channels are formed during the emergence of a sequence of magnetic
bipoles that are squeezed in the compact penumbra of the δ sunspot
and they are highly nonpotential. Formation of channels might be a
precursor of major flares.
Title: Magnetic Flux Loss and Flux Transport in a Decaying Active
Region
Authors: Kubo, M.; Lites, B. W.; Shimizu, T.; Ichimoto, K.
Bibcode: 2008ApJ...686.1447K
Altcode: 2008arXiv0807.4340K
We estimate the temporal change of magnetic flux normal to the solar
surface in a decaying active region by using a time series of the
spatial distribution of vector magnetic fields in the photosphere. The
vector magnetic fields are derived from full spectropolarimetric
measurements with the Solar Optical Telescope aboard Hinode. We compare
a magnetic flux loss rate to a flux transport rate in a decaying sunspot
and its surrounding moat region. The amount of magnetic flux that
decreases in the sunspot and moat region is very similar to magnetic
flux transported to the outer boundary of the moat region. The flux
loss rates [(dF/dt)loss] of magnetic elements with positive
and negative polarities balance each other around the outer boundary of
the moat region. These results suggest that most of the magnetic flux
in the sunspot is transported to the outer boundary of the moat region
as moving magnetic features, and then removed from the photosphere by
flux cancellation around the outer boundary of the moat region.
Title: Magnetic Fields of the Quiet Sun: A New Quantitative
Perspective From Hinode
Authors: Lites, B. W.; Kubo, M.; Socas-Navarro, H.; Berger, T.; Frank,
Z.; Shine, R.; Tarbell, T.; Title, A.; Ichimoto, K.; Katsukawa, Y.;
Tsuneta, S.; Suematsu, Y.; Shimizu, T.; Nagata, S.
Bibcode: 2008ASPC..397...17L
Altcode:
This article summarizes results of studies presented in two papers
already published: Lites et al. (2007a); Lites et al. (2007b). Please
see these for further details.
Title: Evolution of Magnetic Fields at the Boundary of the Penumbra
Authors: Kubo, M.; Ichimoto, K.; Shimizu, T.; Lites, B. W.; Tsuneta,
S.; Suematsu, Y.; Katsukawa, Y.; Nagata, S.; Tarbell, T.; Shine,
R. A.; Title, A. M.
Bibcode: 2008ASPC..397...79K
Altcode:
The formation of moving magnetic features (MMFs) separating from the
penumbra were successfully observed with the Solar Optical Telescope
(SOT) aboard the Hinode satellite. We find that bright features in
the outer penumbra are located at the penumbral spines, which have
magnetic fields more vertical than the surroundings, or located at the
MMFs separating from the spines. This suggests that convection in the
outer penumbra is related to the disintegration of the sunspot.
Title: Balloon-Borne Hard X-Ray Spectrometer Using CdTe Detectors
Authors: Kobayashi, K.; Tsuneta, S.; Tamura, T.; Kumagai, K.;
Katsukawa, Y.; Kubo, M.; Sakamoto, Y.; Kohara, N.; Yamagami, T.;
Saito, Y.; Mori, K.
Bibcode: 2008SoPh..250..431K
Altcode: 2008SoPh..tmp..132K
Spectroscopic observation of solar flares in the hard X-ray energy
range, particularly the 20 ∼ 100 keV region, is an invaluable tool
for investigating the flare mechanism. This paper describes the design
and performance of a balloon-borne hard X-ray spectrometer using CdTe
detectors developed for solar flare observation. The instrument is a
small balloon payload (gondola weight 70 kg) with sixteen 10×10×0.5
mm CdTe detectors, designed for a 1-day flight at 41 km altitude. It
observes in an energy range of 20−120 keV and has an energy resolution
of 3 keV at 60 keV. The second flight on 24 May 2002 succeeded in
observing a class M1.1 flare.
Title: Disintegration of Magnetic Flux in Decaying Sunspots as
Observed with the Hinode SOT
Authors: Kubo, M.; Lites, B. W.; Ichimoto, K.; Shimizu, T.; Suematsu,
Y.; Katsukawa, Y.; Tarbell, T. D.; Shine, R. A.; Title, A. M.; Nagata,
S.; Tsuneta, S.
Bibcode: 2008ApJ...681.1677K
Altcode: 2008arXiv0806.0415K
Continuous observations of sunspot penumbrae with the Solar Optical
Telescope aboard Hinode clearly show that the outer boundary of the
penumbra fluctuates around its averaged position. The penumbral outer
boundary moves inward when granules appear in the outer penumbra. We
discover that such granules appear one after another while moving
magnetic features (MMFs) are separating from the penumbral "spines"
(penumbral features that have fields that are stronger and more vertical
than those of their surroundings). These granules that appear in the
outer penumbra often merge with bright features inside the penumbra
that move with the spines as they elongate toward the moat region. This
suggests that convective motions around the penumbral outer boundary are
related to the disintegration of magnetic flux in the sunspot. We also
find that dark penumbral filaments frequently elongate into the moat
region in the vicinity of MMFs that detach from penumbral spines. Such
elongating dark penumbral filaments correspond to nearly horizontal
fields extending from the penumbra. Pairs of MMFs with positive and
negative polarities are sometimes observed along the elongating dark
penumbral filaments. This strongly supports the notion that such
elongating dark penumbral filaments have magnetic fields with a "sea
serpent"-like structure. Evershed flows, which are associated with the
penumbral horizontal fields, may be related to the detachment of the
MMFs from the penumbral spines, as well as to the formation of the MMFs
along the dark penumbral filaments that elongate into the moat region.
Title: The cosmic ray primary composition at the knee region from
lateral distributions of atmospheric C˘erenkov photons in extensive
air showers
Authors: Tokuno, H.; Kakimoto, F.; Ogio, S.; Harada, D.; Kurashina, Y.;
Tsunesada, Y.; Tajima, N.; Matsubara, Y.; Morizawa, A.; Burgoa, O.;
Gotoh, E.; Kadota, K.; Kaneko, T.; Kubo, M.; Miranda, P.; Mizobuchi,
T.; Mizumoto, Y.; Murakami, K.; Nakatani, H.; Nishi, K.; Shimoda,
S.; Shirasaki, Y.; Toyoda, Y.; Velarde, A.; Yamada, K.; Yamada, Y.;
Yoshii, H.
Bibcode: 2008APh....29..453T
Altcode:
We have measured the lateral distributions of atmospheric C˘erenkov
photons associated with extensive air showers to study the chemical
composition of the primary cosmic rays in the energy range from 10
14.5 to 10 16 eV, so called knee region. The
atmospheric C˘erenkov photon detectors were installed in the EAS
array at Mt. Chacaltaya. The measured lateral distributions were
fitted with an empirical formula with a parameter which is sensitive
to mass numbers of primary cosmic rays. A three species model (proton,
carbon, and iron nuclei) is used for the chemical composition study
of the present experiment. To determine the mixing ratio of the three
species, the distributions of the parameter for the observed events
were examined to reproduce those for the simulated ones calculated
with the CORSIKA code using the QGSJET hadronic interaction model. From
the obtained mixing ratio of the three species, we determined the mean
logarithmic mass numbers of primary cosmic rays, <ln A>, in the
knee region. The present result shows that the values of <ln A>
are higher than the logarithmic mass number for carbon and the proton
component is no more dominant at the knee.
Title: Frequent Occurrence of High-Speed Local Mass Downflows on
the Solar Surface
Authors: Shimizu, T.; Lites, B. W.; Katsukawa, Y.; Ichimoto, K.;
Suematsu, Y.; Tsuneta, S.; Nagata, S.; Kubo, M.; Shine, R. A.; Tarbell,
T. D.
Bibcode: 2008ApJ...680.1467S
Altcode: 2008arXiv0804.1167S
We report on new spectropolarimetric measurements with simultaneous
filter imaging observation, revealing the frequent appearance of
polarization signals indicating high-speed, probably supersonic,
downflows that are associated with at least three different
configurations of magnetic fields in the solar photosphere. The
observations were carried out with the Solar Optical Telescope on
board the Hinode satellite. High-speed downflows are excited when a
moving magnetic feature is newly formed near the penumbral boundary of
sunspots. Also, a new type of downflows is identified at the edge of
sunspot umbra that lack accompanying penumbral structures. These may
be triggered by the interaction of magnetic fields swept by convection
with well-concentrated magnetic flux. Another class of high-speed
downflows are observed in quiet Sun and sunspot moat regions. These are
closely related to the formation of small concentrated magnetic flux
patches. High-speed downflows of all types are transient time-dependent
mass motions. These findings suggest that the excitation of supersonic
mass flows are one of the key observational features of the dynamical
evolution occurring in magnetic-field fine structures on the solar
surface.
Title: The Solar Optical Telescope of Solar-B ( Hinode): The Optical
Telescope Assembly
Authors: Suematsu, Y.; Tsuneta, S.; Ichimoto, K.; Shimizu, T.; Otsubo,
M.; Katsukawa, Y.; Nakagiri, M.; Noguchi, M.; Tamura, T.; Kato, Y.;
Hara, H.; Kubo, M.; Mikami, I.; Saito, H.; Matsushita, T.; Kawaguchi,
N.; Nakaoji, T.; Nagae, K.; Shimada, S.; Takeyama, N.; Yamamuro, T.
Bibcode: 2008SoPh..249..197S
Altcode: 2008SoPh..tmp...26S
The Solar Optical Telescope (SOT) aboard the Solar-B satellite (Hinode)
is designed to perform high-precision photometric and polarimetric
observations of the Sun in visible light spectra (388 - 668 nm)
with a spatial resolution of 0.2 - 0.3 arcsec. The SOT consists of
two optically separable components: the Optical Telescope Assembly
(OTA), consisting of a 50-cm aperture Gregorian with a collimating lens
unit and an active tip-tilt mirror, and an accompanying Focal Plane
Package (FPP), housing two filtergraphs and a spectro-polarimeter. The
optomechanical and optothermal performance of the OTA is crucial to
attain unprecedented high-quality solar observations. We describe in
detail the instrument design and expected stable diffraction-limited
on-orbit performance of the OTA, the largest state-of-the-art solar
telescope yet flown in space.
Title: Emergence of a helical flux rope and prominence formation
Authors: Okamoto, T. J.; Tsuneta, S.; Lites, B. W.; Kubo, M.; Yokoyama,
T.; Berger, T. E.; Ichimoto, K.; Katsukawa, Y.; Nagata, S.; Shibata,
K.; Shimizu, T.; Shine, R. A.; Suematsu, Y.; Tarbell, T. D.; Title,
A. M.
Bibcode: 2008AGUSMSP43B..06O
Altcode:
We report a discovery about emergence of a helical flux rope. The
episode may be related to the formation and evolution of an active
region prominence. Statistical studies by previous authors indicate that
numerous prominences have the inverse-polarity configuration suggesting
the helical magnetic configurations. There are two theoretical
models about formation of such a coronal helical magnetic field in
association with prominences: flux rope model and sheared-arcade
model. We have so far no clear observational evidence to support
either model. In order to find a clue about the formation of the
prominence, we had continuous observations of NOAA AR 10953 with the
SOT during 2007 April 28 to May 9. A prominence was located over the
polarity inversion line in the south-east of the main sunspot. These
observations provided us with a time series of vector magnetic fields
on the photosphere under the prominence. We found four new features:
(1) The abutting opposite-polarity regions on the two sides along
the polarity inversion line first grew laterally in size and then
narrowed. (2) These abutting regions contained vertically-weak,
but horizontally-strong magnetic fields. (3) The orientations of
the horizontal magnetic fields along the polarity inversion line on
the photosphere gradually changed with time from a normal- polarity
configuration to an inverse-polarity one. (4) The horizontal-magnetic
field region was blueshifted. These indicate that helical flux rope
emerges from below the photosphere into the corona along the polarity
inversion line under the prominence. We suggest that this supply of a
helical magnetic flux possibly into the corona is related to formation
and maintenance of active-region prominences.
Title: Changes of Magnetic Structure in 3-D Associated with the X3.4
Flare of 2006 December 13
Authors: Jing, J.; Wiegelmann, T.; Suematsu, Y.; Kubo, M.; Wang, H.
Bibcode: 2008AGUSMSP51C..02J
Altcode:
Recent observations demonstrated that sunspot structure can change
rapidly and irreversibly after flares. One of the most puzzling results
is the increase in magnetic shear around flaring magnetic polarity
inversion line after flares. However, all these observations were
made at the photosphere level. We study the altitude variation of the
non-potentiality of the magnetic fields associated with the 4B/X3.4
flare of 2006 December 13. The vector magnetograms with unprecedented
quality from Hinode before and after the flare are used as the boundary
conditions to extrapolate the 3-dimensional non-linear force-free
magnetic fields and the potential fields. The former are computed
with the optimization algorithm and the latter with Green's function
method. At the photosphere boundary, magnetic shear increases after the
flare in a local area close to the flaring magnetic polarity inversion
line. Two measures of the magnetic non-potentiality, the weighted mean
shear θw and the total magnetic shear θwB, are calculated in this area
at progressively higher altitude. By comparing their altitude variation
profiles before and after the flare, we find that the non-potentiality
of the local area increases after the flare below ~8 Mm and decreases
from that height to ~70 Mm. Beyond 70 Mm, the magnetic fields approach
potential for both times.
Title: Disintegration of Magnetic Flux in Decaying Sunspots as
Observed with the Hinode/SOT
Authors: Kubo, M.; Lites, B. W.; Ichimoto, K.; Shimizu, T.; Suematsu,
Y.; Katsukawa, Y.; Tarbell, T. D.; Shine, R. A.; Title, A. M.; Nagata,
S.; Tsuneta, S.
Bibcode: 2008AGUSMSP31B..01K
Altcode:
Continuous observations of sunspot penumbrae with the Solar Optical
Telescope aboard Hinode clearly show that the outer boundary of the
penumbra fluctuates around its averaged position. The penumbral outer
boundary moves inward when granules appear in the outer penumbra. We
discover that such granules appear one after another while moving
magnetic features (MMFs) are separating from the penumbral "spines"
(penumbral features having fields that are stronger and more vertical
than their surroundings). These granules that appear in the outer
penumbra often merge with bright features inside the penumbra that move
with spines as they elongate toward the moat region. This suggests that
convective motions around the penumbral outer boundary are related to
disintegration of magnetic flux in the sunspot. We also find that dark
penumbral filaments frequently elongate into the moat region in the
vicinity of MMFs that detach from penumbral spines. Such elongating
dark penumbral filaments correspond to nearly horizontal fields
extending from the penumbra. Pairs of MMFs with positive and negative
polarities are sometimes observed along the elongating dark penumbral
filaments. This strongly supports the notion that such elongating dark
penumbral filaments have magnetic fields with a "sea serpent"-like
structure. Evershed flows, which are associated with the penumbral
horizontal fields, may be related to detachment of the MMFs from the
penumbral spines, as well as to the formation of the MMFs along the
dark penumbral filaments that elongate into the moat region.
Title: Net circular polarization of sunspots in high spatial
resolution
Authors: Ichimoto, K.; Tsuneta, S.; Suematsu, Y.; Katsukawa, Y.;
Shimizu, T.; Lites, B. W.; Kubo, M.; Tarbell, T. D.; Shine, R. A.;
Title, A. M.; Nagata, S.
Bibcode: 2008A&A...481L...9I
Altcode:
Context: Net circular polarization (NCP) of spectral lines in
sunspots has been most successfully explained by the presense of
discontinuities in the magnetic field inclination and flow velocity
along the line-of-sight in the geometry of the embedded flux tube model
of penumbrae (Δγ-effect).
Aims: The fine scale structure of
NCP in a sunspot is examined with special attention paid to spatial
relations of the Evershed flow to confirm the validity of the present
interpretation of the NCP of sunspots.
Methods: High resolution
spectro-polarimetric data of a positive-polarity sunspot obtained
by the Solar Optical Telescope aboard Hinode are analysed.
Results: A positive NCP is associated with the Evershed flow
channels in both limb-side and disk center-side penumbrae and with
upflows in the penumbra at disk center. The negative NCP in the disk
center-side penumbra is generated in inter-Evershed flow channels.
Conclusions: The first result is apparently inconsistent with the
current explanation of NCP with the Δγ-effect but rather suggests a
positive correlation between the magnetic field strength and the flow
velocity as the cause of the NCP. The second result serves as strong
evidence for the presence of gas flows in inter-Evershed flow channels.
Title: Changes of Magnetic Structure in Three Dimensions Associated
with the X3.4 Flare of 2006 December 13
Authors: Jing, Ju; Wiegelmann, Thomas; Suematsu, Yoshinori; Kubo,
Masahito; Wang, Haimin
Bibcode: 2008ApJ...676L..81J
Altcode:
Recent observations demonstrated that sunspot structure can change
rapidly and irreversibly after flares. One of the most puzzling results
is the increase in magnetic shear around the flaring magnetic polarity
inversion line after flares. However, all these observations were
made at the photosphere level. In this Letter, we study the altitude
variation of the nonpotentiality of the magnetic fields associated
with the 4B/X3.4 flare of 2006 December 13. The vector magnetograms
with unprecedented quality from Hinode before and after the flare are
used as the boundary conditions to extrapolate the three-dimensional
nonlinear force-free magnetic fields and the potential fields. The
former are computed with the optimization algorithm and the latter with
the Green's function method. At the photosphere boundary, magnetic shear
increases after the flare in a local area close to the flaring magnetic
polarity inversion line. Two measures of the magnetic nonpotentiality,
the weighted mean shear θw and the total magnetic shear
θwB, are calculated in this area at progressively higher
altitude. By comparing their altitude variation profiles before and
after the flare, we find that the nonpotentiality of the local area
increases after the flare below ~8 Mm and decreases from that height
to ~70 Mm. Beyond 70 Mm, the magnetic fields approach potential for
both times.
Title: Emergence of a Helical Flux Rope under an Active Region
Prominence
Authors: Okamoto, Takenori J.; Tsuneta, Saku; Lites, Bruce W.; Kubo,
Masahito; Yokoyama, Takaaki; Berger, Thomas E.; Ichimoto, Kiyoshi;
Katsukawa, Yukio; Nagata, Shin'ichi; Shibata, Kazunari; Shimizu,
Toshifumi; Shine, Richard A.; Suematsu, Yoshinori; Tarbell, Theodore
D.; Title, Alan M.
Bibcode: 2008ApJ...673L.215O
Altcode: 2008arXiv0801.1956O
Continuous observations were obtained of NOAA AR 10953 with the Solar
Optical Telescope (SOT) on board the Hinode satellite from 2007 April
28 to May 9. A prominence was located over the polarity inversion
line (PIL) to the southeast of the main sunspot. These observations
provided us with a time series of vector magnetic fields on the
photosphere under the prominence. We found four features: (1) The
abutting opposite-polarity regions on the two sides along the PIL first
grew laterally in size and then narrowed. (2) These abutting regions
contained vertically weak but horizontally strong magnetic fields. (3)
The orientations of the horizontal magnetic fields along the PIL on
the photosphere gradually changed with time from a normal-polarity
configuration to an inverse-polarity one. (4) The horizontal magnetic
field region was blueshifted. These indicate that helical flux rope
was emerging from below the photosphere into the corona along the PIL
under the preexisting prominence. We suggest that this supply of a
helical magnetic flux to the corona is associated with evolution and
maintenance of active region prominences.
Title: The Horizontal Magnetic Flux of the Quiet-Sun Internetwork
as Observed with the Hinode Spectro-Polarimeter
Authors: Lites, B. W.; Kubo, M.; Socas-Navarro, H.; Berger, T.; Frank,
Z.; Shine, R.; Tarbell, T.; Title, A.; Ichimoto, K.; Katsukawa, Y.;
Tsuneta, S.; Suematsu, Y.; Shimizu, T.; Nagata, S.
Bibcode: 2008ApJ...672.1237L
Altcode:
Observations of very quiet Sun using the Solar Optical
Telescope/Spectro-Polarimeter (SOT/SP) aboard the Hinode spacecraft
reveal that the quiet internetwork regions are pervaded by horizontal
magnetic flux. The spatial average horizontal apparent flux density
derived from wavelength-integrated measures of Zeeman-induced linear
polarization is BTapp = 55 Mx cm -2, as
compared to the corresponding average vertical apparent flux density of
| BLapp| = 11 Mx cm -2. Distributions
of apparent flux density are presented. Magnetic fields are organized on
mesogranular scales, with both horizontal and vertical fields showing
"voids" of reduced flux density of a few granules spatial extent. The
vertical fields are concentrated in the intergranular lanes, whereas the
stronger horizontal fields are somewhat separated spatially from the
vertical fields and occur most commonly at the edges of the bright
granules. High-S/N observations from disk center to the limb help
to constrain possible causes of the apparent imbalance between |
BLapp| and BTapp, with
unresolved structures of linear dimension on the surface smaller by at
least a factor of 2 relative to the SOT/SP angular resolution being one
likely cause of this discrepancy. Other scenarios for explaining this
imbalance are discussed. The horizontal fields are likely the source of
the "seething" fields of the quiet Sun discovered by Harvey et al. The
horizontal fields may also contribute to the "hidden" turbulent flux
suggested by studies involving Hanle effect depolarization of scattered
radiation.
Title: Hinode Observations of Flux Emergence in Quiet and Active
Regions
Authors: Lites, B. W.; Centeno, R.; Kubo, M.; Socas-Navarro, H. Berger,
T.; Frank, Z.; Shine, R.; Tarbell, T.; Title, A.; Ichimoto, K.;
Katsukawa, Y.; Tsuneta, S.; Suematsu, Y.; Shimizu, T.; Nagata, S.
Bibcode: 2008ASPC..383...71L
Altcode:
We review briefly the observational understanding of emergence of
flux in both the quiet Sun and active regions in the light of first
results from the joint Japan/US/UK Hinode mission. That spacecraft
is now providing us with our first continuous, high resolution
measurements of the photospheric vector magnetic field, along with
high resolution observations of the thermal and dynamic properties
of the chromosphere and corona. This review is intended to present a
few very early results and to highlight the potential for discovery
offered by this extraordinary new mission. The discovery of ubiquitous
horizontal magnetic flux in the quiet internetwork regions is presented.
Title: Mangetic field properties at the footpoints of solar
microflares (active-region transient brightenings)
Authors: Shimizu, T.; Kano, R.; Katsukawa, Y.; Kubo, M.; Deluca, E.;
Ichimoto, K.; Lites, B.; Nagata, S.; Sakao, T.; Shine, R.; Suematsu,
Y.; Tarbell, T.; Title, A.; Tsuneta, S.
Bibcode: 2007AGUFMSH52C..06S
Altcode:
Solar active regions produce numerous numbers of small-scale explosive
energy releases, i.e., microflares, which are captured by imaging
observations in soft X-rays as transient brightenings of small-scale
coronal loops. Thanks to advanced performance of X-Ray Telescope (XRT)
onboard the Hinode satellite, we can investigate finer structure
of the brightening X-ray sources in more details than we did with
Yohkoh data. One of important questions on microflares is what causes
microflares. The simultaneous visible-light observations by the Solar
Optical Telescope (SOT) allow us to explore magnetic activities
and magnetic field configuration at the photospheric footpoints
of brightening loops, giving key observations to investigate the
question. For our investigations of corona-photosphere magnetic
coupling, we have established co-alignment between SOT and XRT
with accuracy better than 1 arcsec (Shimizu et al. 2007, PASJ in
press). It turns out that Ca II H observations are very useful
to identify the exact positions of footpoints of X-ray transient
brightening loops. Small "Kernels" are sometimes observed in Ca II H
and they may be signature of highly accelerated non-thermal particles
impinging on chromosphere. As already shown in Shimizu et al.(2002),
frequent transient brightenings are observed at the locations where
emerging activities are on going. However, another type of brightening
triggering mechanism should exist to explain some observed multiple-loop
brightenings. In the multiple-loop brightenings, multiple loops are
magnetically in parallel with each other and no apparent magnetic
activities, such as emerging and canceling, are observed at and near
the footpoints. This paper will present SOT observations of some
microflares observed with XRT.
Title: Magnetic activity responsible for sunspot decay
Authors: Kubo, Masahito
Bibcode: 2007AstHe.100..649K
Altcode:
Small magnetic elements moving outward are generally observed in the
zone surrounding mature sunspots. Such small magnetic elements were
thought to carry away magnetic flux from sunspots. A relationship
between the small magnetic elements and sunspot decay is investigated
using vector magnetic fields in the photosphere. It is found that
there are small magnetic elements with magnetic fields horizontal
and relatively vertical to the solar surface located on the lines
extrapolated from the horizontal and vertical components of the
penumbral fields, respectively. This means that magnetic fields
of the small magnetic elements are originated from the penumbral
magnetic fields. In addition, the authors have obtained observational
results suggesting that the magnetic elements having vertical fields
with polarity same as the sunspot are alone responsible for the
disintegration of the sunspot.
Title: Twisting Motions of Sunspot Penumbral Filaments
Authors: Ichimoto, K.; Suematsu, Y.; Tsuneta, S.; Katsukawa, Y.;
Shimizu, T.; Shine, R. A.; Tarbell, T. D.; Title, A. M.; Lites, B. W.;
Kubo, M.; Nagata, S.
Bibcode: 2007Sci...318.1597I
Altcode:
The penumbra of a sunspot is composed of numerous thin, radially
extended, bright and dark filaments carrying outward gas flows
(the Evershed flow). Using high-resolution images obtained by the
Solar Optical Telescope aboard the solar physics satellite Hinode, we
discovered a number of penumbral bright filaments revealing twisting
motions about their axes. These twisting motions are observed only
in penumbrae located in the direction perpendicular to the symmetry
line connecting the sunspot center and the solar disk center, and
the direction of the twist (that is, lateral motions of intensity
fluctuation across filaments) is always from limb side to disk-center
side. Thus, the twisting feature is not an actual twist or turn of
filaments but a manifestation of dynamics of penumbral filaments with
three-dimensional radiative transfer effects.
Title: Magnetic Field Properties of Flux Cancellation Sites
Authors: Kubo, M.; Shimizu, T.
Bibcode: 2007ApJ...671..990K
Altcode:
It has been frequently observed in longitudinal magnetograms that
magnetic elements disappear when a magnetic polarity element approaches
and collides with another polarity element. We examine 12 collision
events observed with the Advanced Stokes Polarimeter. We find formation
of new magnetic connection between the colliding opposite polarity
elements both in the photosphere and in the corona. In some cases,
the opposite polarity elements to be collided appear at different
times and at widely separated positions. Magnetic fields horizontal to
the solar surface are spontaneously formed on the polarity inversion
line (PIL) between such colliding elements, and transient bright X-ray
loops connecting the opposite polarity elements appear. We suggest that
formation of the coronal loops and the photospheric horizontal fields
are due to magnetic reconnection between the colliding field lines,
possibly at multiple locations with different heights. We also find that
a global change in the direction of the photospheric horizontal fields
between the colliding elements occurs in association with formation
and disappearance of Hα dark filaments. Initial horizontal fields
perpendicular to the PIL become parallel to the PIL, when dark filaments
are observed along the PIL. They return to being perpendicular to the
PIL at around the time of the disappearance of the dark filament. This work was completed while the author was affiliated with the
National Astronomical Observatory of Japan and University of Tokyo.
Title: Continuous Plasma Outflows from the Edge of a Solar Active
Region as a Possible Source of Solar Wind
Authors: Sakao, Taro; Kano, Ryouhei; Narukage, Noriyuki; Kotoku,
Jun'ichi; Bando, Takamasa; DeLuca, Edward E.; Lundquist, Loraine L.;
Tsuneta, Saku; Harra, Louise K.; Katsukawa, Yukio; Kubo, Masahito;
Hara, Hirohisa; Matsuzaki, Keiichi; Shimojo, Masumi; Bookbinder, Jay
A.; Golub, Leon; Korreck, Kelly E.; Su, Yingna; Shibasaki, Kiyoto;
Shimizu, Toshifumi; Nakatani, Ichiro
Bibcode: 2007Sci...318.1585S
Altcode:
The Sun continuously expels a huge amount of ionized material into
interplanetary space as the solar wind. Despite its influence on the
heliospheric environment, the origin of the solar wind has yet to
be well identified. In this paper, we report Hinode X-ray Telescope
observations of a solar active region. At the edge of the active region,
located adjacent to a coronal hole, a pattern of continuous outflow of
soft-x-ray emitting plasmas was identified emanating along apparently
open magnetic field lines and into the upper corona. Estimates of
temperature and density for the outflowing plasmas suggest a mass
loss rate that amounts to ~1/4 of the total mass loss rate of the
solar wind. These outflows may be indicative of one of the solar wind
sources at the Sun.
Title: Biosignatures in modern sulfates: texture, composition and
depositional environments of gypsum deposits at Guerrero Negro,
Baja, Mexico
Authors: Vogel, M. B.; Des Marais, D. J.; Jahnke, L. L.; Turk, K.;
Kubo, M.
Bibcode: 2007AGUFM.B31D0622V
Altcode:
Gypsum (CaSO4·H2O) is an important phase in biogeochemistry
and sedimentology as a mineral sink for sulfur, a paleoclimatic
indicator, and an endolithic niche for phototrophic and chemotrophic
bacteria. Sulfate deposits are also important targets of exploration
for evidence of habitable environments and life on Mars. Gypsum
deposits from a range of sedimentary environments at the Guerrero
Negro crystallizer ponds and sabkha settings were investigated
for microscale structure and composition to differentiate fabrics
formed under microbial influence from those formed under abiogenic
conditions. Sub-sedimentary gypsum forms in sabkha environments as mm
to cm scale selenite discs (termed bird beak gypsum; Warren, 2006) and
selenite disc aggregates. Selenite discs and other sub-sedimentary
gypsum are characterized by a sinuous axial microtexture and
poikilitically enclosed detrital particles. Sub-aqueous gypsum forms
as cements, granules (termed gypsooids), and massive botryoidal
crusts that line the sediment water interface and margins of managed
crystallizer ponds and natural anchialine pools. Sub-aqueous gypsum
exhibits a wide range of textures and mineral/biofilm associations
that include amorphous to euhedral, tabular, needle and lensoidal
morphologies. Elemental sulfur forms rinds on prismatic, growth aligned
gypsum twins and reticulate magnesian carbonate is interspersed
with both twinned crystals and rosette aggregates in stratified
sub-aqueous environments. Intracrystalline biofilms and cell material
was observed in association with nearly all sub-aqueous morphologies
but only scarce evidence has been found for intercrystalline microbial
communities. Columnar microbial communities living in anchialine pools
were found to host precipitation of mm scale gypsum granules in their
EPS matrix. Fine scale gypsum textures are unlikely to persist through
diagenetic alteration, but understanding their primary associations
with sulfur and carbonates is necessary for interpreting sulfates or
their replacement phases in the ancient record.
Title: Center-to-Limb Variation of Stokes V Asymmetries in Solar
Pores Observed with the Hinode Spectro-Polarimeter
Authors: Morinaga, Shuji; Nagata, Shin'ichi; Ichimoto, Kiyoshi;
Suematsu, Yoshinori; Tsuneta, Saku; Katsukawa, Yukio; Shimizu,
Toshifumi; Shine, Richard A.; Tarbell, Theodore D.; Title, Alan M.;
Lites, Bruce; Kubo, Masahito; Sakurai, Takashi
Bibcode: 2007PASJ...59S.613M
Altcode:
Here we present spectro-polarimetric measurements of several pores
and the surrounding regions taken with the Solar Optical Telescope
aboard Hinode at various viewing angles. We analyzed the Stokes V
area asymmetry, and confirmed that it is depressed at the center of
the pores, while it shows large positive values (a blue lobe larger
than a red lobe) in the surrounding area; this is consistent with a
previous report. In addition to this ring of positive asymmetry, we
found regions of alternating positive and negative area asymmetries
when weak V regions were observed near the solar limb. The positive
asymmetry occurs on the disk-center side and the negative asymmetry
on the limb side of the magnetic concentrations. These center-to-limb
variations of the Stokes V area asymmetry can be interpreted as being
a systematic inflow of plasma into the magnetic concentrations from
their surroundings.
Title: Initial Results on Line-of-Sight Field Calibrations of SP/NFI
Data Taken by SOT/Hinode
Authors: Chae, Jongchul; Moon, Yong-Jae; Park, Young-Deuk; Ichimoto,
Kiyoshi; Sakurai, Takashi; Suematsu, Yoshinori; Tsuneta, Saku;
Katsukawa, Yukio; Shimizu, Toshifumi; Shine, Richard A.; Tarbell,
Theodore D.; Title, Alan M.; Lites, Bruce; Kubo, Masahito; Nagata,
Shin'ichi; Yokoyama, Takaaki
Bibcode: 2007PASJ...59S.619C
Altcode:
We present initial results on the line-of-sight field calibration
of the two kinds of Stokes I and V data taken by the Solar Optical
Telescope on the satellite Hinode: spectral profiles of Stokes I and V
parameters recorded on the Spectro-polarimeter (SP), and monochromatic
images of the same parameters recorded on the Narrow-band Filter Imager
(NFI). By applying the center-of-gravity method to the SP data of
AR10930 taken on 2006 December 11, we determined the line-of-sight field
at every location in the active region. As a result, we found that the
line-of-sight field strength ranges up to 2kG in plages, even without
taking into account the filling factor, and up to 3.5kG or higher values
inside the umbra of the major sunspot. We calibrated the NFI data in
reference to the field determined from the SP data. In regions outside
the sunspots and the penumbral regions, we adopted a linear relation,
B|| = βV / I, between the circular polarization, V / I,
and the line-of-sight field strength, B||, and obtained β =
23.5kG in regions outside the sunspots, and β = 12.0kG in penumbral
regions. In umbral regions of sunspots, a first-order polynomial was
adopted to model the reversal of the polarization signal over the
field strength.
Title: Response of the Solar Atmosphere to Magnetic Flux Emergence
from Hinode Observations
Authors: Li, Hui; Sakurai, Takashi; Ichimito, Kiyoshi; Suematsu,
Yoshinori; Tsuneta, Saku; Katsukawa, Yukio; Shimizu, Toshifumi; Shine,
Richard A.; Tarbell, Theodore D.; Title, Alan M.; Lites, Bruce; Kubo,
Masahito; Nagata, Shin'ichi; Kotoku, Jun; Shibasaki, Kiyoto; Saar,
Steven H.; Bobra, Monica
Bibcode: 2007PASJ...59S.643L
Altcode:
No abstract at ADS
Title: Hinode Observations of Horizontal Quiet Sun Magnetic Flux
and the ``Hidden Turbulent Magnetic Flux''
Authors: Lites, Bruce; Socas-Navarro, Hector; Kubo, Masahito; Berger,
Thomas; Frank, Zoe; Shine, Richard A.; Tarbell, Theodore D.; Title,
Alan M.; Ichimoto, Kiyoshi; Katsukawa, Yukio; Tsuneta, Saku; Suematsu,
Yoshinori; Shimizu, Toshifumi
Bibcode: 2007PASJ...59S.571L
Altcode:
We present observations of magnetic fields of the very quiet Sun
near disk center using the Spectro-Polarimeter of the Solar Optical
Telescope aboard the Hinode satellite. These observations reveal for
the first time the ubiquitous presence of horizontal magnetic fields in
the internetwork regions. The horizontal fields are spatially distinct
from the vertical fields, demonstrating that they are not arising mainly
from buffeting of vertical flux tubes by the granular convection. The
horizontal component has an average ``apparent flux density'' of
55Mxcm-2 (assuming the horizontal field structures are
spatially resolved), in contrast to the average apparent vertical flux
density of 11Mxcm-2. The vertical fields reside mainly in
the intergranular lanes, whereas the horizontal fields occur mainly
over the bright granules, with a preference to be near the outside
edge of the bright granules. The large apparent imbalance of vertical
and horizontal flux densities is discussed, and several scenarios are
presented to explain this imbalance.
Title: Hinode Observations of a Vector Magnetic Field Change
Associated with a Flare on 2006 December 13
Authors: Kubo, Masahito; Yokoyama, Takaaki; Katsukawa, Yukio; Lites,
Bruce; Tsuneta, Saku; Suematsu, Yoshinori; Ichimoto, Kiyoshi; Shimizu,
Toshifumi; Nagata, Shin'ichi; Tarbell, Theodore D.; Shine, Richard A.;
Title, Alan M.; Elmore David
Bibcode: 2007PASJ...59S.779K
Altcode: 2007arXiv0709.2397K
Continuous observations of the flare productive active region 10930
were successfully carried out with the Solar Optical Telescope aboard
the Hinode spacecraft during 2006 December 6 to 19. We focused on the
evolution of photospheric magnetic fields in this active region, and the
magnetic field properties at the site of the X3.4 class flare, using
a time series of vector field maps with high spatial resolution. The
X3.4 class flare occurred on 2006 December 13 at the apparent
collision site between the large, opposite polarity umbrae. Elongated
magnetic structures with alternatingly positive and negative polarities
resulting from flux emergence appeared one day before the flare in the
collision site penumbra. Subsequently, the polarity inversion line
at the collision site became very complicated. The number of bright
loops in CaII H increased during the formation of these elongated
magnetic structures. Flare ribbons and bright loops evolved along
the polarity inversion line and one footpoint of the bright loop was
located in a region having a large departure of the field azimuth angle
with respect to its surroundings. SOT observations with high spatial
resolution and high polarization precision revealed temporal change in
the fine structure of magnetic fields at the flare site: some parts of
the complicated polarity inversion line then disappeared, and in those
regions the azimuth angle of the photospheric magnetic field changed by
about 90°, becoming more spatially uniform within the collision site.
Title: Fine-Scale Structures of the Evershed Effect Observed by the
Solar Optical Telescope aboard Hinode
Authors: Ichimoto, Kiyoshi; Shine, Richard A.; Lites, Bruce; Kubo,
Masahito; Shimizu, Toshifumi; Suematsu, Yoshinori; Tsuneta, Saku;
Katsukawa, Yukio; Tarbell, Theodore D.; Title, Alan M.; Nagata,
Shin'ichi; Yokoyama, Takaaki; Shimojo, Masumi
Bibcode: 2007PASJ...59S.593I
Altcode:
The small-scale structure of the Evershed effect is being studied
using data obtained by the Spectropolarimeter and the Broadband Filter
Imager of the Solar Optical Telescope aboard Hinode. We find that the
Evershed flow starts at the leading edge of inwardly migrating bright
penumbral grains, and turns to nearly a horizontal flow preferentially
in the dark lanes of the penumbra. A number of small elongated regions
that have an upward motion of ∼ 1kms-1 are found in the
deep photosphere distributed over the penumbra. They are cospatial
with bright grains and have relatively horizontal magnetic fields. A
number of patches having a strong downward motion associated with the
opposite magnetic polarity from the sunspot are also found in the mid
and outer penumbra. They could be identified as foot points of the
Evershed flow channels, though the identification of individual pairs
is not straightforward. Our results provide strong support for some
recent findings from ground-based high-resolution observations, and
are in general agreement with the well-known picture of the uncombed
structure of the penumbra, in which the penumbrae consist of rising
flux tubes carrying nearly horizontal Evershed flows embedded in more
vertical background magnetic fields.
Title: Flare Ribbons Observed with G-band and FeI 6302Å, Filters
of the Solar Optical Telescope on Board Hinode
Authors: Isobe, Hiroaki; Kubo, Masahito; Minoshima, Takashi; Ichimoto,
Kiyoshi; Katsukawa, Yukio; Tarbell, Theodore D.; Tsuneta, Saku; Berger,
Thomas E.; Lites, Bruce; Nagata, Shin'ichi; Shimizu, Toshifumi; Shine,
Richard A.; Suematsu, Yoshinori; Title, Alan M.
Bibcode: 2007PASJ...59S.807I
Altcode: 2007arXiv0711.3946I
The Solar Optical Telescope (SOT) on board the Hinode satellite observed
an X3.4 class flare on 2006 December 13. A typical two-ribbon structure
was observed, not only in the chromospheric CaII H line, but also in
the G-band and FeI 6302Å line. The high-resolution, seeing-free images
achieved by SOT revealed, for the first time, sub-arcsec fine structures
of the ``white light'' flare. The G-band flare ribbons on sunspot
umbrae showed a sharp leading edge, followed by a diffuse inside,
as well as a previously known core-halo structure. The underlying
structures, such as umbral dots, penumbral filaments, and granules,
were visible in the flare ribbons. Assuming that the sharp leading
edge was directly heated by a particle beam and the diffuse parts were
heated by radiative back-warming, we estimated the depth of the diffuse
flare emission using an intensity profile of the flare ribbon. We found
that the depth of the diffuse emission was about 100km or less from
the height of the source of radiative back-warming. The flare ribbons
were also visible in the Stokes-V images of FeI 6302Å, as a transient
polarity reversal. This is probably related to a ``magnetic transient''
reported in the literature. The intensity increase in Stokes-I images
indicates that the FeI 6302Å line was significantly deformed by the
flare, which may cause such a magnetic transient.
Title: Hinode SP Vector Magnetogram of AR10930 and Its
Cross-Comparison with MDI
Authors: Moon, Yong-Jae; Kim, Yeon-Han; Park, Young-Deuk; Ichimoto,
Kiyoshi; Sakurai, Takashi; Chae, Jongchul; Cho, Kyung Suk; Bong,
Suchan; Suematsu, Yoshinori; Tsuneta, Saku; Katsukawa, Yukio; Shimojo,
Masumi; Shimizu, Toshifumi; Shine, Richard A.; Tarbell, Theodore D.;
Title, Alan M.; Lites, Bruce; Kubo, Masahito; Nagata, Shin'ichi;
Yokoyama, Takaaki
Bibcode: 2007PASJ...59S.625M
Altcode:
We present one Hinode Spectropolarimeter (SP) magnetogram of AR 10930
that produced several major flares. The inversion from Stokes profiles
to magnetic field vectors was made using the standard Milne-Eddington
code. We successfully applied the Uniform Shear Method for resolving
the 180° ambiguity to the magnetogram. The inversion gave very strong
magnetic field strengths (near 4500 gauss) for a small portion of area
in the umbra. Considering that the observed V-profile of 6301.5Å was
well-fitted as well as a direct estimation of the Zeeman splitting
results in 4300-4600 gauss, we think that the field strengths
should not be far from the actual value. A cross-comparison of the
Hinode SP and SOHO MDI high resolution flux densities shows that the
MDI flux density could be significantly underestimated by about a
factor of two. In addition, it has a serious negative correlation
(the so-called Zeeman saturation effect) with the Hinode SP flux
density for umbral regions. Finally, we could successfully obtain
a recalibrated MDI magnetogram that has been corrected for the
Zeeman saturation effect using not only a pair of MDI intensity and
magnetogram data simultaneously observed, but also the relationship
from the cross-comparison between the Hinode SP and MDI flux densities.
Title: Formation Process of a Light Bridge Revealed with the Hinode
Solar Optical Telescope
Authors: Katsukawa, Yukio; Yokoyama, Takaaki; Berger, Thomas E.;
Ichimoto, Kiyoshi; Kubo, Masahito; Lites, Bruce; Nagata, Shin'ichi;
Shimizu, Toshifumi; Shine, Richard A.; Suematsu, Yoshinori; Tarbell,
Theodore D.; Title, Alan M.; Tsuneta, Saku
Bibcode: 2007PASJ...59S.577K
Altcode: 2007arXiv0709.2527K
The Solar Optical Telescope (SOT) on-board Hinode successfully and
continuously observed the formation process of a light bridge in a
matured sunspot of the NOAA active region 10923 for several days with
high spatial resolution. During its formation, many umbral dots were
observed to be emerging from the leading edges of penumbral filaments,
and rapidly intruding into the umbra. The precursor of the light bridge
formation was also identified as a relatively slow inward motion of
the umbral dots, which emerged not near the penumbra, but inside the
umbra. The spectro-polarimeter on SOT provided physical conditions in
the photosphere around the umbral dots and the light bridges. We found
that the light bridges and the umbral dots had significantly weaker
magnetic fields associated with upflows relative to the core of the
umbra, which implies that there was hot gas with weak field strength
penetrating from the subphotosphere to near the visible surface inside
those structures. There needs to be a mechanism to drive the inward
motion of the hot gas along the light bridges. We suggest that the
emergence and the inward motion are triggered by a buoyant penumbral
flux tube as well as subphotospheric flow crossing the sunspot.
Title: Formation of Moving Magnetic Features and Penumbral Magnetic
Fields with Hinode/SOT
Authors: Kubo, Masahito; Ichimoto, Kiyoshi; Shimizu, Toshifumi;
Tsuneta, Saku; Suematsu, Yoshinori; Katsukawa, Yukio; Nagata,
Shin'ichi; Tarbell, Theodore D.; Shine, Richard A.; Title, Alan M.;
Frank, Zoe A.; Lites, Bruce; Elmore, David
Bibcode: 2007PASJ...59S.607K
Altcode: 2007arXiv0709.1853K
Vector magnetic fields of moving magnetic features (MMFs) were well
observed with the Solar Optical Telescope (SOT) aboard the Hinode
satellite. We focused on the evolution of three MMFs with the SOT in
this study. We found that an MMF having relatively vertical fields
with the same polarity as the sunspot was detached from the penumbra
around the granules appearing in the outer penumbra. This suggests
that granular motions in the outer penumbra are responsible for
disintegration of the sunspot. Two MMFs with polarity opposite to
the sunspot are located around the outer edge of horizontal fields
extending from the penumbra. This is evidence that the MMFs with
polarity opposite to the sunspot are the prolongation of penumbral
horizontal fields. Redshifts larger than the sonic velocity in the
photosphere are detected for some of the MMFs with polarity opposite
to the sunspot.
Title: Magnetic Correspondence between Moving Magnetic Features and
Penumbral Magnetic Fields
Authors: Kubo, M.; Shimizu, T.
Bibcode: 2007ASPC..369..145K
Altcode:
We investigate vector magnetic fields of moving magnetic features
(MMFs) around a mature sunspot with the Advanced Stokes Polarimeter
and SOHO/MDI. In addition to the classical isolated MMFs identified by
visually inspecting the time sequence of MDI magnetograms, we focus
on any diffuse moving magnetic features that are not recognized
as classical MMFs. This feature is called non-isolated MMFs. The
non-isolated MMFs occupy most of the moat region surrounding the
sunspot, and have nearly horizontal magnetic fields with both
polarities. We find that the isolated MMFs located on the lines
extrapolated from the horizontal component of the penumbral uncombed
structure have magnetic fields similar to the non-isolated MMFs. This
suggests that such MMFs are part of horizontal fields extended from
the penumbra. The isolated MMFs located on the lines extrapolated from
the vertical component of the uncombed structure have vertical fields
with polarity same as the sunspot. Our observation shows that such
MMFs are detached from the vertical component of the penumbra. Their
flux transport rate is estimated to be 1-3 times larger than a flux
loss rate of the sunspot. The isolated vertical MMFs alone can be
responsible for decaying the sunspot.
Title: Estimate on SOT Light Level in Flight with Throughput
Measurements in SOT Sun Tests
Authors: Shimizu, T.; Kubo, M.; Tarbell, T. D.; Berger, T. E.;
Suematsu, Y.; Ichimoto, K.; Katsukawa, Y.; Miyashita, M.; Noguchi,
M.; Nakagiri, M.; Tsuneta, S.; Elmore, D. F.; Lites, B. W.
Bibcode: 2007ASPC..369...51S
Altcode:
The SOT (Solar Optical Telescope, e.g., Shimizu 2004) optical
system consists of 50cm-aperture optical telescope (OTA) and focal
plane instrument (FPP). The solar light into the telescope penetrates
through many optical elements located in OTA and FPP before illuminating
CCDs. Natural solar light was fed to the integrated SOT in sun tests for
verifying various optical aspects including the confirmation of photon
throughput. CCD exposures provide the number of photons accumulated
in an exposure duration with a clean-room test condition. To estimate
the absolute intensity of the solar light at the telescope entrance
in the clean-room test condition, we developed a pinhole-PSD sensor
for simultaneous monitoring the solar light outside the clean room
and measured the transmission of light through two flat mirrors of
the heliostat and clean-room entrance window glass as a function of
wavelength. The PSD sensor was pre-calibrated with continuous monitoring
the solar light in a day long under a clear constant sky condition,
determining the earth atmospheric attenuation and the PSD output for
the solar light on orbit. These throughput measurements have provided
an estimate on photon throughput for the SOT flight model. The results
confirm suitable number of photons without saturation for proper CCD
exposures in flight.
Title: Emergence of Small-Scale Magnetic Loops in the Quiet-Sun
Internetwork
Authors: Centeno, R.; Socas-Navarro, H.; Lites, B.; Kubo, M.; Frank,
Z.; Shine, R.; Tarbell, T.; Title, A.; Ichimoto, K.; Tsuneta, S.;
Katsukawa, Y.; Suematsu, Y.; Shimizu, T.; Nagata, S.
Bibcode: 2007ApJ...666L.137C
Altcode: 2007arXiv0708.0844C
We study the emergence of magnetic flux at very small spatial
scales (less than 2") in the quiet-Sun internetwork. To this aim,
a time series of spectropolarimetric maps was taken at disk center
using the instrument SP/SOT on board Hinode. The LTE inversion of
the full Stokes vector measured in the Fe I 6301 and 6302 Å lines
allows us to retrieve the magnetic flux and topology in the region
of study. In the example presented here, the magnetic flux emerges
within a granular structure. The horizontal magnetic field appears
prior to any significant amount of vertical field. As time goes on,
the traces of the horizontal field disappear, while the vertical dipoles
drift-carried by the plasma motions-toward the surrounding intergranular
lanes. These events take place within typical granulation timescales.
Title: Chromospheric Micro-jets Discovered Above Sunspot Penumbrae
Authors: Katsukawa, Yukio; Tsuneta, S.; Suematsu, Y.; Ichimoto, K.;
Shimizu, T.; Kubo, M.; Nagata, S.; Berger, T.; Tarbell, T.; Shine,
R.; Title, A.
Bibcode: 2007AAS...210.9413K
Altcode: 2007BAAS...39..219K
The Solar Optical Telescope (SOT) aboard HINODE allows us to observe
dynamical activities in the solar photosphere and the chromosphere
with high and stable image quality of 0.2 arcseconds. This superior
performance of SOT provides new findings of fine-scale transient
activities occurring in the chromosphere. In this paper, we report
discovery of fine-scale jet-like phenomena ubiquitously observed
above sunspot penumbrae. The jets are identified in image sequences
of a sunspot taken through a Ca II H line filter at 3968A. The Ca II
H line is sensitive to about 10^4 K plasma in the chromosphere. Their length is typically between 3000 and 10000km, and their
width is smaller than 500km. It is notable that their lifetime
is shorter than 1 minute. Those small spatial and temporal scale
possibly makes it difficult to identify the phenomena in existing
ground-based observations. The jets are easily identified when a
sunspot is located far from the disk center, and motion of the bright
features suggests that mass is erupted from lower chromosphere to upper
atmosphere. Velocities of the motion are estimated to be 50 to 100 km/s
from their lateral motion of intensity patterns. The velocities are much
faster than sound speeds in the chromosphere. A possible cause of such
high-speed jets is magnetic reconnection at the lower chromosphere
resulted from fluted magnetic configuration in penumbrae which is
suggested by vector magnetic field measurements in the photosphere.
Title: Hinode Data Calibration For Precise Image Co-alignment:
XRT vs. SOT
Authors: Shimizu, Toshifumi; DeLuca, E. E.; Lundquist, L.; Sakao,
T.; Kubo, M.; Narukage, N.; Kano, R.; Katsukawa, Y.; Ichimoto, K.;
Suematsu, Y.; Tsuneta, S.; Tarbell, T.; Shine, D.; Hinode Team
Bibcode: 2007AAS...210.9417S
Altcode: 2007BAAS...39Q.220S
From late October in 2006, Hinode solar optical telescope (SOT) has
started to produce series of 0.2-0.3 arcsec visible-light images,
revealing dynamical behaviors of solar magnetic fields on the
solar surface. Simultaneously, Hinode X-ray telescope (XRT) has been
providing 1 arcsec resolution X-ray images of the solar corona, giving
the location of heating and dynamics occuring in the corona. Precise
image co-alignment of SOT data on XRT data with sub-arcsec accuracy is
required to provide new information regarding connecting the corona to
the photosphere. This presentation will give an introduction of Hinode
between-telescopes' image co-alignment to SPD participants. For active
region observations with sunspots, sunspots can be used as fiducial to
co-align the data from the two telescopes each other. Satellite jitter
in order of 1 arcsec or less is included in the series of XRT data,
whereas image stabilization system (correlation tracker) removes the
satellite jitter from the series of SOT images. Telescope pointings show
orbital variation in order of a few arcsec, which can be well predicted
from Hinode orbit information. Modeling co-alignment is under study
and it is the only precise method for quiet Sun and limb observations.
Title: Hinode/SOT Observations Of Apparent "Thermal Plume" Motions
In A Solar Prominence
Authors: Berger, Thomas; Tarbell, T.; Slater, G.; Tsuneta, S.;
Suematsu, Y.; Ichimoto, K.; Katsukawa, Y.; Shimizu, T.; Kubo, M.;
Nagata, S.
Bibcode: 2007AAS...210.9433B
Altcode: 2007BAAS...39..222B
We present 396.8 nm Ca II H-line observations of a large
hedgerow, or "sheet", prominence seen on the solar western limb
on 30-November-2006. The 16 second cadence observations show dark
channels rising vertically at speeds of approximately 10 km/sec to
heights of about 15 Mm above the limb. Many of the motions end in
vortical overturning near the top of the sheet . Bright downflows of
similar speed are also seen within the sheet, often in association
with a dark channel that has risen to the top of the sheet. The dark
channels are suggestive of hot material rising in thermal plumes
within the prominence sheet. Similarly, the bright material motions
appear to be density enhanced regions of turbulent downflow. Current
models of sheet prominences do not include the observed dynamics. In
these models, the prominence plasma is in a low-beta state and is
constrained to move only along magnetic field lines. However the
motions observed here are extremely complex, implying either that the
magnetic field lines are undergoing turbulent motion, thus tangling
and reconnecting constantly, or that the plasma is not constrained
by the field and is in a high-beta convective state. We measure the
motion of several representative "plumes" and downflows, estimate the
density and temperature of the prominence plasma, and suggest several
avenues for further investigation. This work was supported by
NASA under the Hinode/SOT contract NNM07AA01C.
Title: Hinode/SOT Observation of Fine Structure of the Evershed Flow
Authors: Ichimoto, Kiyoshi; Suematsu, Y.; Tsuneta, S.; Katsukawa, Y.;
Shimojo, M.; Kubo, M.; Shimizu, T.; Shine, R.; Tarbell, T.; Title,
A.; Lites, B.; Elmore, D.; Yokoyama, T.; Nagaka, S.
Bibcode: 2007AAS...210.9408I
Altcode: 2007BAAS...39..218I
Small scale structure of the Evershed effect was studied using the
Spectropolarimeter (SP) and Broadband Filter Imager (BFI) of SOT aboard
Hinode. SP maps and high cadence continuum images of BFI coverting
entire sunspots are used to investigate the spatial distribution of
the flow field, brightness and magnetic fields. It is revealed that the
Evershed flow starts at the front edge of inwardly migrating penumbral
grains with an upward velocity component and turns to nearly holizontal
flow preferentially in dark lanes (or dark core of filaments) of the
penumbra. Our results are in general agreement with the well known
uncombed penumbral concept in which the Evershed flow takes place
in nearly holizontal field channels. We discovered a number of tiny
elongated regions in deep photosphere in which there is an obvious
upward motion of 1-1.5km/s distributing over the penumbra. They
could be identified as the 'foot points' of the individual Evershed
flow channels. Cross-correlation among the flow speed, intensity,
magnetic field strength and inclination, and distribution of string
down flows in and around the penumbra will also be discussed.
Title: Continuous Upflow of Plasmas at the Edge of an Active Region
as Revealed by the X-ray Telescope (XRT) aboard Hinode
Authors: Sakao, Taro; Kano, R.; Narukage, N.; Kotoku, J.; Bando, T.;
DeLuca, E. E.; Lundquist, L. L.; Golub, L.; Kubo, M.; Katsukawa, Y.;
Tsuneta, S.; Hara, H.; Matsuzaki, K.; Shimojo, M.; Shibasaki, K.;
Shimizu, T.; Nakatani, I.
Bibcode: 2007AAS...210.7205S
Altcode: 2007BAAS...39Q.179S
We present X-ray imaging observations with Hinode X-Ray Telescope (XRT)
of an active region NOAA AR 10942 made in the period of 20-22 February
2007. A prominent feature that drew our particular attention is that
there revealed continuous upflow of soft-X-ray-emitting plasmas along
apparently-open field lines towards the outer corona emanating from the
edge of the active region. The field lines are originated from
an ensamble of small spots of following polarity, and are located at
a border between the active region and an adjacent equatorial coronal
hole(s) located to the east. The upflow was observed to be continuous
throughout the three days of observation intervals with projected
velocity of 140 km/s, accompanied with undulating motion of the field
lines. We assert that these upflowing plasmas would be a possible
source of slow solar wind material, which supports a foresighted
notion which grew out of interplanetary scintillation observations
that slow solar wind most likely has its origin in the vicinity of
active regions with large flux expansion (Kojima et al. 1999). A
preliminaty analysis indicates that the temperature of the upflowing
material near the base of the field lines is 1.3 MK with number density
of 2 × 109 /cm3. Assuming that all the material
is to escape to the interplanetary space, this leads to a mass loss
rate of 2 × 1011 g/s which amounts to a good fraction of
the total mass loss rate for solar wind. It is noteworthy that, even
apart from this unique upflow, we see continuous (up)flows of plasmas
anywhere around (surrounding) the active region. Details of the
upflow will be presented and their possible implication to slow solar
wind discussed.
Title: Magnetic Flux Emergence In The Quiet Sun Photosphere
Authors: Centeno, Rebecca; Lites, B.; Socas-Navarro, H.; Frank,
Z.; Shine, R.; Tarbell, T.; Title, A.; Ichimoto, K.; Tsuneta, S.;
Katsukawa, Y.; Suematsu, Y.; Kubo, M.; Shimizu, T.
Bibcode: 2007AAS...210.9406C
Altcode: 2007BAAS...39..218C
We study the emergence of magnetic flux at very small spacial scales
(less than 1 arcsec) in the quiet Sun internetwork. To this aim, several
time series of spectropolarimetric maps were taken at disk center using
the instrument SP/SOT on board Hinode. The LTE inversion of the full
Stokes vector measured in the Fe I 6301 and 6302 lines will allow us
to retrieve the magnetic flux and topology in the region of study. We
find that the magnetic flux emerges typically within the granular
structures. In many cases, the horizontal magnetic field appears
prior to any significant amount of vertical field. As time goes on,
the traces of the horizontal field dissapear while the the vertical
dipoles drift -carried by the plasma motions- towards the surrounding
intergranular lanes. Sometimes they stay trapped there for a while
but they eventually either disappear by disgregation/cancelation
or agregate to other magnetic field concentrations giving rise to
larger flux elements. The time scale of these events is of the order
of 10-20 minutes.
Title: Formation of Moving Magnetic Features and Penumbral Magnetic
Fields
Authors: Kubo, Masahito; Ichimoto, K.; Shimizu, T.; Tsuneta, S.;
Suematsu, Y.; Katsukawa, Y.; Nagata, S.; Lites, B. W.; Frank, Z.;
Tarbell, T. D.; Shine, R. A.; Title, A. M.
Bibcode: 2007AAS...210.9410K
Altcode: 2007BAAS...39..218K
We investigate the formation process of Moving Magnetic Features
(MMFs) observed with Hinode/SOT. Moving magnetic features are small
magnetic elements moving outward in the moat region surrounding
mature sunspots. We derive vector magnetic fields of MMFs around
simple sunspots near the disk center. Most of MMFs with polarity
opposite to the sunspot have large redshift around the penumbral outer
boundary. We find that some of them have Doppler velocities of about
10 km/s and such large Doppler motion is observed only in the Stokes
V profile. The Stokes Q and U profiles in the same pixel do not have
any significant Doppler motions. Horizontal magnetic fields of the
penumbra frequently extend to the moat region and the MMFs having
horizontal fields with polarity same as the sunspot are formed. The
MMFs with polarity opposite to the sunspot appear around the outer
edge of the extending penumbral fields. We also find penumbral spines,
which have more vertical magnetic fields than the surroundings, branch
off at their outer edge and MMFs having relatively vertical fields
with polarity same as the sunspot are detached from the outer edge
of the branch. The branch of penumbral spine is formed when granular
cells in the moat region go into the penumbra.
Title: Ubiquitous Horizontal Magnetic Fields in the Quiet Solar
Photosphere as Revealed by HINODE Meaurements
Authors: Lites, Bruce W.; Socas Navarro, H.; Berger, T.; Frank,
Z.; Shine, R.; Tarbell, T.; Title, A.; Ichimoto, K.; Katsukawa,
Y.; Tsuneta, S.; Suematsu, Y.; Kubo, M.; Shimizu, T.; Nagata, S.;
Hinode Team
Bibcode: 2007AAS...210.6303L
Altcode: 2007BAAS...39..171L
Measurements with the HINODE Spectro-Polarimeter (SP) of the quiet
Sun allow characterization of the weak, mixed-polarity magnetic
flux at the highest angular resolution to date (0.3"), and with good
polarimetric sensitivity(0.025% relative to the continuum). The image
stabilization of the HINODE spacecraft allows long integrations with
degradation of the image quality only by the evolution of the solar
granulation. From the Stokes V profile measurements we find an average
solar "Apparent Flux Density" of 14 Mx cm-2, with significant Stokes V
signals at every position on the disk at all times. However, there are
patches of meso-granular size (5-15") where the flux is very weak. At
this high sensitivity, transverse fields produce measurable Stokes
Q,U linear polarization signals over a majority of the area, with
apparent transverse flux densities in the internetwork significantly
larger than the corresponding longitudinal flux densities. When viewed
at the center of the solar disk, the Stokes V signals (longitudinal
fields) show a preference for occurrence in the intergranular lanes,
and the Q,U signals occur preferably over the granule interiors,
but neither association is exclusive. Hinode is an international
project supported by JAXA, NASA, PPARC and ESA. We are grateful to the
Hinode team for all their efforts in the design, build and operation
of the mission.
Title: Hinode/SOT Observations of Sunspot Penumbral Dynamics and
Evolution
Authors: Shine, Richard A.; Hagenaar, M.; Tarbell, T.; Title, A.;
Lites, B.; Ichimoto, K.; Tsuneta, S.; Katsakawa, Y.; Suematsu, Y.;
Nagata, S.; Kubo, M.; Shimizu, T.
Bibcode: 2007AAS...210.9407S
Altcode: 2007BAAS...39..218S
The Solar Optical Telescope (SOT) on the Hinode satellite (launched
October 2006) has obtained long and nearly continuous time series of
several large sunspots including those in NOAA AR's 10923, 10925,
and 10930. Here we use high resolution movies taken primarily with
the broad band Ca II (396.8nm) and G band (430.5nm) channels and
magnetograms taken with the 630.2nm narrow band channel to study
the details and short term evolution of penumbral fine structures
as well as the long term evolution of the sunspots. We compute flow
maps and use space/time slices to track motions of Evershed clouds,
penumbral grains, and visualize oscillations. The data contain examples
of penumbral formation and disintegration including "orphan" penumbra
(i.e., penumbra without an obvious umbra). There is also an interesting
instance of "colliding" penumbra in AR 10930 as two sunspots of opposite
polarity converged. The zone of apparent shear was associated with
several flares. This work was supported by NASA contract NNM07AA01C
Title: Optical Performance of the Solar Optical Telescope aboard
HINODE
Authors: Suematsu, Yoshinori; Ichimoto, K.; Katsukawa, Y.; Otsubo,
M.; Tsuneta, S.; Nakagiri, M.; Noguchi, M.; Tamura, T.; Kato, Y.;
Hara, H.; Miyashita, M.; Shimizu, T.; Kubo, M.; Sakamoto, Y.
Bibcode: 2007AAS...210.9402S
Altcode: 2007BAAS...39Q.217S
The Solar Optical Telescope (SOT) carried by HINODE was designed
to perform a high-precision polarimetric observation of the Sun
in visible light spectra with a spatial resolution of 0.2 - 0.3
arcseconds. The SOT is a sophistcated instrument and consists of two
separate optical parts; the Optical Telescope Assembly (OTA) which is
50 cm aperture Gregorian telescope feeding the light into following
observing instruments which is called the focal plane package (FPP)
made of two filtergraphs and a spectro-polarimeter. The performance
of the OTA is important because a spatial resolution and its temporal
stability is mainly determined by this component. To keep the OTA in
moderate temperature and optical thermal deformation small, it equipped
newly designed components such as a heat dump and a secondary field stop
aluminum mirror with high reflectivity silver coating and a temperature
low-sensitive apochromatic collimataing lens unit with a UV/IR cut
coating on the first surface. In addition, the SOT has an active image
stabilization system consisting of correlation tracker, tip-tilt mirror
and its controller against satellite pointing jitter. It was confirmed
that this system freezes residual motion to the 0.01 arcsecond level
on orbit. The image of sub-arcsecond G-band (430.5 nm) bright points
clearly indicates that the SOT achieves the diffraction-limit on orbit;
this is also confirmed using a phase diversity method. In this paper,
we describe details of the design and on-orbit performance of the OTA.
Title: Vector Magnetic Fields of Moving Magnetic Features and Flux
Removal from a Sunspot
Authors: Kubo, M.; Shimizu, T.; Tsuneta, S.
Bibcode: 2007ApJ...659..812K
Altcode:
Moving magnetic features (MMFs) are small photospheric magnetic
elements moving outward in the zone (moat region) surrounding mature
sunspots. Vector magnetic fields and horizontal motion of the classical
MMFs (called isolated MMFs hereafter) are investigated using coordinated
ASP and MDI observations. Their magnetic and velocity properties
are compared to nearby magnetic features, including moat fields
surrounding the isolated MMFs and penumbral uncombed structure. The
moat fields are defined as nonisolated MMFs because they also move
outward from sunspots. The nonisolated MMFs have nearly horizontal
magnetic fields of both polarities. We find that the isolated MMFs
located on the lines extrapolated from the horizontal component of the
uncombed structure have magnetic fields similar to the nonisolated
MMFs. This suggests that the MMFs with nearly horizontal fields are
intersections of horizontal fields extended from the penumbra with the
photospheric surface. We find clear evidence that the isolated MMFs
located on the lines extrapolated from the vertical component of the
uncombed structure have vertical field lines with polarity same as the
sunspot. This correspondence shows that such MMFs are detached from
the spine (vertical) component of the penumbra. We estimate that the
magnetic flux carried by the vertical MMFs is about 1-3 times larger
than the flux loss of the sunspot. We suggest that the isolated vertical
MMFs alone can transport sufficient magnetic flux and are responsible
for the disappearance and disintegration of the sunspot.
Title: Organic geochemistry of endoevaporitic environments: Microbial
diversity and lipid biomarkers from gypsum deposits at the E.S.S.A
Salt Works, Guerrero Negro, Baja, Mexico
Authors: Vogel, M. B.; Des Marais, D. J.; Jahnke, L. L.; Turk, K. A.;
Kubo, M. D.
Bibcode: 2006AGUFM.B11D..07V
Altcode:
We report lipid biomarker distributions and microbial diversity of
endoevaporitic microbial communities from the gypsum crystallizer
pond (Pond #9; ~170 % salinity) at the Exportadora de Sal, (ESSA)
salt works in Guerrero Negro, Baja California Sur, Mexico. According
to phylogenetic analysis using 16S rRNA sequences, gypsum crusts
from this system host stratified communities of unicellular
cyanobacteria (orange Euhalothece), filamentous cyanobacteria (green
Oscillatoria), purple sulfur bacteria (Chromatium), and other halophilic
microorganisms. Lipids collected from spatially discrete horizons of
the crust indicate a shift in C16, C18 and C19 fatty acids from lower
concentrations in the upper aerobic layers to higher concentrations in
the deeper anaerobic zones of the crust. Compound specific isotopic
analyses (CSIA) of fatty acids differentiate the more abundant C16,
C18 and C19 homologues as isotopically lighter (~ -20% to -25% δ13C
VPDB) from C15, C17 and C20 homologues which are isotopically heavier (~
-14% to -19% δ13C VPDB) and occur in lower abundance. CSIA of multiple
compound classes reveals that gypsum domain lipids have significantly
lighter δ13C values than those of lipids from the laminated benthic
microbial mats living at lower salinities (i.e. ~100% to 115% salinity)
in the ESSA system. This isotopic effect is consistent with intensive
internal nutrient cycling within the crust. Squalane/squalene were
detected in extracts from the gypsum crust indicating the presence
of archaea. Diploptene is the most abundant triterpenoid of the C28
C32 hopanoids. Branched alkanes with quaternary substituted carbons
(BAQCs) were also detected. These compounds have been linked with
sulfur oxidizing microbial activity, which is known to be a major
respiratory process in the crust's internal O2 budget (Sørensen et al.,
2004). Abundant organosulfur compounds (OSC) and thiacycloalkanes in
extracts indicate a vigorous internal sulfur cycle that influences both
microbial populations and organic matter diagenesis. This locality is
relevant to extremophile studies because it is a biological analogue
for evaporite deposits recently discovered on Mars and constitutes
a complex hypersaline ecosystem where extreme sulfate concentrations
affect carbon and oxygen cycles.
Title: Hard X-Ray Spectral Observation of a High-Temperature
Thermal Flare
Authors: Kobayashi, Ken; Tsuneta, Saku; Tamura, Tomonori; Kumagai,
Kazuyoshi; Katsukawa, Yukio; Kubo, Masahito; Sakamoto, Yasushi;
Kohara, Naoki; Yamagami, Takamasa; Saito, Yoshitaka
Bibcode: 2006ApJ...648.1239K
Altcode:
We report on the analysis of a thermal flare observed by a newly
developed balloon-borne hard X-ray spectrometer. This instrument uses
CdTe detectors and can observe the 20-120 keV hard X-ray range, with
3.0 keV energy resolution at 60 keV. During the 2002 May 24 flight,
it successfully observed a class M1.1 flare. This flare observation
shows no detectable flux above 35 keV, and its spectrum is consistent
with a superhot thermal source with the temperature varying from 44
to 20 MK. Partial observation of the flare by the RHESSI satellite is
consistent with this result. The Nobeyama Radio Polarimeters (NORP)
observation of this flare shows no detectable polarization. The NORP
light curves show impulsive features at 3.75 GHz that can be explained
as thermal gyrosynchrotron emission, and this flux is consistent with
observed X-ray spectra if a magnetic field of 275 G is assumed. Slower
varying features seen in the NORP data are consistent with the
lower temperature (``hot'') thermal source of 10-15 MK seen in soft
X-rays. We conclude that this flare shows no observable signature of
nonthermal electrons, and all observed features are consistent with
a purely thermal event. This serves as a strong indication that a
nonthermal electron beam is not always the dominant energy source of
plasma heating in solar flares.
Title: Source Structures of the 1998 November 28 X-Class Flare and
Electron Acceleration
Authors: Huang, Guangli; Nakajima, Hiroshi; Masuda, Satoshi; Kobayashi,
Ken; Kubo, Masahito
Bibcode: 2006PASJ...58...37H
Altcode:
We studied the 1998 November 28 X-class flare, which showed
long-duration, two-ribbon α emission. (1) A soft X-ray loop system
developed along the major magnetic neutral line in the impulsive
phase. Hard X-ray and microwave emissions due to nonthermal electrons
were located in some limited regions. While the compact hard X-ray
loop was associated with weak, diffuse soft X-ray emission, two large
microwave loops did not have soft X-ray counterparts. (2) Time profiles
of two large microwave loops were similar to that of hard X-ray total
emission, which emanated mostly from the compact source, even in the
fine time structure in the rising phase. (3) A super-hot thermal hard
X-ray source appeared around the impulsive peak and was located along
the major magnetic neutral line in the declining phase, coinciding with
the bright soft X-ray emission. The thermal component can be explained
within the standard reconnection model to the extent that the super-hot
thermal plasma was heated in the large soft X-ray loop. However, the
nonthermal electrons were accelerated in a localized region where
three loops interacted with each other. The inferred configuration
may be a more complicated form of the double-loop interaction model
proposed by Hanaoka (1996) and Nishio et al. (1997).
Title: Completion of Solar-B/Optical Telescope flight model
Authors: Suematsu, Yoshinori; Ichimoto, Kiyosi; Shimizu, Toshifumi;
Otsubo, Masashi; Nakagiri, Masao; Noguchi, Motokazu; Tamura, Tomonori;
Katsukawa, Yukio; Kato, Yoshihiro; Hara, Hirohisa; Miyashita, Masakuni;
Tsuneta, Saku; Kubo, Masahito; Sakamoto, Yasushi
Bibcode: 2005ARAOJ...7...52S
Altcode:
No abstract at ADS
Title: Observation of solar flare hard X-ray spectra using CdTe
detectors
Authors: Kobayashi, Ken; Tsuneta, Saku; Tamura, Tomonori; Kumagai,
Kazuyoshi; Katsukawa, Yukio; Kubo, Masahito; Sakamoto, Yasushi;
Kohara, Naoki; Yamagami, Takamasa; Saito, Yoshitaka; Mori, Kunishiro;
Kato, Genzo
Bibcode: 2005naoj.book...33K
Altcode:
No abstract at ADS
Title: Solar-B/Optical Telescope flight model is coming up
Authors: Suematsu, Yoshinori; Ichimoto, Kiyoshi; Shimizu, Toshifumi;
Otsubo, Masashi; Nakagiri, Masao; Noguchi, Motokazu; Tamura, Tomonori;
Kato, Yoshihiro; Hara, Hirohisa; Miyashita, Masakuni; Tsuneta, Saku;
Katsukawa, Yukio; Kubo, Masahito; Sakamoto, Yasushi
Bibcode: 2005naoj.book....4S
Altcode:
No abstract at ADS
Title: New clean room for space instrumentation
Authors: Noguchi, Motokazu; Nakagiri, Masao; Suematsu, Yoshinori;
Tsuneta, Saku; Kubo, Masahito
Bibcode: 2005naoj.book...37N
Altcode:
No abstract at ADS
Title: The first build-up of the Solar-B flight models
Authors: Hara, Hirohisa; Ichimoto, Kiyoshi; Otsubo, Masashi; Katsukawa,
Yukio; Kato, Yoshihiro; Kano, Ryohei; Kumagai, Kazuyoshi; Shibasaki,
Kiyoto; Shimizu, Toshifumi; Shimojo, Masumi; Suematsu, Yoshinori;
Tamura, Tomonori; Tsuneta, Saku; Noguchi, Motokazu; Nakagiri, Masao;
Miyashita, Masakuni; Watanabe, Tesuya; Kosuchi, Takeo; Sakao, Taro;
Matsuzaki, Keiichi; Kitakoshi, Yasunori; Kubo, Masahito; Sakamoto,
Yasushi
Bibcode: 2005ARAOJ...7...46H
Altcode:
No abstract at ADS
Title: Hard X-Ray Spectral Observation of a High-Temperature
Thermal Flare
Authors: Kobayashi, K.; Katsukawa, Y.; Kubo, M.; Sakamoto, Y.; Kohara,
N.; Tsuneta, S.; Tamura, T.; Kumagai, K.; Yamagami, T.; Saito, Y.
Bibcode: 2004ASPC..325..353K
Altcode:
No abstract at ADS
Title: Vector Magnetic Field of Moving Magnetic Features around a
Well-Developed Sunspot
Authors: Kubo, M.; Shimizu, T.
Bibcode: 2004ASPC..325..143K
Altcode:
No abstract at ADS
Title: The Solar Optical Telescope onboard the Solar-B
Authors: Ichimoto, Kiyoshi; Tsuneta, Saku; Suematsu, Yoshinori;
Shimizu, Toshifumi; Otsubo, Masashi; Kato, Yoshihiro; Noguchi,
Motokazu; Nakagiri, Masao; Tamura, Tomonori; Katsukawa, Yukio; Kubo,
Masahito; Sakamoto, Yasushi; Hara, Hirohisa; Minesugi, Kenji; Ohnishi,
Akira; Saito, Hideo; Kawaguchi, Noboru; Matsushita, Tadashi; Nakaoji,
Toshitaka; Nagae, Kazuhiro; Sakamoto, Joji; Hasuyama, Yoshihiro;
Mikami, Izumi; Miyawaki, Keizo; Sakurai, Yasushi; Kaido, Nobuaki;
Horiuchi, Toshihida; Shimada, Sadanori; Inoue, Toshio; Mitsutake,
Masaaki; Yoshida, Norimasa; Takahara, Osamu; Takeyama, Norihide;
Suzuki, Masaharu; Abe, Shunichi
Bibcode: 2004SPIE.5487.1142I
Altcode:
The solar optical telescope onboard the Solar-B is aimed to perform a
high precision polarization measurements of the solar spectral lines
in visible wavelengths to obtain, for the first time, continuous
sets of high spatial resolution (~0.2arcsec) and high accuracy
vector-magnetic-field map of the sun for studying the mechanisms
driving the fascinating activity phenomena occurring in the solar
atmosphere. The optical telescope assembly (OTA) is a diffraction
limited, aplanatic Gregorian telescope with an aperture of Φ500mm. With
a collimating lens unit and an active folding mirror, the OTA provides
a pointing-stabilized parallel beam to the focal plane package (FPP)
with a field of view of about 360x200arcsec. In this paper we identify
the key technical issues of OTA for achieving the mission goal and
describe the basic concepts in its optical, mechanical and thermal
designs. The strategy to verify the in-orbit performance of the
telescope is also discussed.
Title: Observation of solar flare hard X-ray spectra using CdTe
detectors
Authors: Kobayashi, K.; Tsuneta, S.; Tamura, T.; Kumagai, K.;
Katsukawa, Y.; Kubo, M.; Sakamoto, Y.; Kohara, N.; Yamagami, T.;
Saito, Y.; Mori, K.
Bibcode: 2004AdSpR..33.1786K
Altcode:
We present the design and initial flight results of a balloon-borne
hard X-ray spectrometer for observing solar flares. The instrument
is designed for quantitative observation of nonthermal and thermal
components of solar flare hard X-ray emission, and has an energy range
of 15-120 keV and an energy resolution of 3 keV. The instrument is
a small (gondola weight 70 kg) system equipped with sixteen 10 ×
10 × 0.5 mm CdTe detectors, and designed for a 1-day flight at 41
km altitude. Detector temperature of -15 °C was achieved through
radiative cooling alone. Pre-flight tests confirmed that all detectors
exceeded the target 3 keV resolution. No flares were observed during
the 2001 flight, but the second flight on May 24, 2002 succeeded
in observing a class M1.1 flare. Preliminary analysis indicates the
observed spectrum is consistent with a purely thermal plasma at an
unusually high temperature of 47 mK.
Title: The evoluton of vector magnetic fields in an emerging flux
region
Authors: Kubo, Masahito; Shimizu, Toshifumi; Tsuneta, Saku; Lites,
B. W.
Bibcode: 2004naoj.book...41K
Altcode:
No abstract at ADS
Title: Observation of solar flare hard X-ray spectra using CdTe
detectors
Authors: Kobayashi, Ken; Tsuneta, Saku; Tamura, Tomonori; Kumagai,
Kazuyoshi; Katsukawa, Yukio; Kubo, Masahito; Sakamoto, Yasushi;
Kohara, Naoki; Yamagami, Takamasa; Saito, Yoshitaka; Mori, Kunishiro;
Kato, Genzo
Bibcode: 2004naoj.book...38K
Altcode:
No abstract at ADS
Title: Thermo-optical testing of the solar optical telescope of
the Solar-B
Authors: Ichimoto, Kiyoshi; Nakagiri, Masao; Suematsu, Yoshinori;
Tamura, Tomonori; Tsuneta, Saku; Noguchi, Motokazu; Kato, Yoshihiro;
Otsubo, Seiji; Katsukawa, Yukio; Kubo, Masahito
Bibcode: 2004naoj.book....6I
Altcode:
No abstract at ADS
Title: Development and flight performance of the sun sensor for
balloon observation
Authors: Tamura, Tomonori; Kobayashi, Ken; Tsuneta, Saku; Kubo,
Masahito; Katsukawa, Yukio
Bibcode: 2003RNAOJ...6..117T
Altcode:
We developed a sun-sensor for the balloon mission to observe solar
flare hard X-ray spectra using CdTe detectors. The sensor utilizes a
position-sensitive detector (PSD) with a pinhole, and has 60 degrees ×
60 degrees field-of-view with a 1 degree resolution. The sun-sensor
operated nominally during the two flights. We report the design,
ground calibration, and flight performance.
Title: The Evolution of Vector Magnetic Fields in an Emerging
Flux Region
Authors: Kubo, M.; Shimizu, T.; Lites, B. W.
Bibcode: 2003ApJ...595..465K
Altcode:
Collaborative observations of NOAA Active Region 9231 were carried out
during 9 days in 2000 November using the Advanced Stokes Polarimeter
(ASP), Yohkoh/SXT, TRACE, and SOHO/MDI, in order to record the
evolution of the photospheric magnetic field and its related coronal
response. During this period an emerging flux region (EFR) appeared in
the photosphere near the well-developed leading sunspot of this region,
and subsequently bright bundles of coronal loops formed between the
main concentrations of opposite magnetic polarity. The structure of
the photospheric field comprising the EFR is classified into three
regions: (1) the main bipolar magnetic flux of the EFR; (2) two small,
rapidly emerging bipoles within the EFR; and (3) the remainder of
the EFR excluding the other two regions. Two small, rapidly emerging
bipoles are observed within a few hours of their first appearance at
the photosphere. Examination of the vector magnetic field, its filling
factor, and Doppler motion within the EFR shows that the young emerging
magnetic field is nearly horizontal, the intrinsic field strength is
weaker than that of the surrounding magnetic field (~500 G), and the
weak field has a high filling factor (>80%) and upward motion (<1
km s-1). At both ends of the horizontal field structure we
find that the magnetic field strength increases to about 1500 G and
the filling factor drops to about 40% as the magnetic field becomes
vertical in orientation during its first 12 hr. This field strength
is typical of the field within the main bipolar magnetic flux, but
the filling factor increases to 80% during the following 2 days. The
process for organizing magnetic field configuration including convective
collapse and flux concentration provides one possible explanation
of the evolution of the field strength and the filling factor in the
EFR. In addition, aymmetric surface distributions of magnetic field
inclination were observed in the horizontal magnetic field area in the
EFR. These asymmetric distributions were also observed in the small,
young, emerging bipoles. This may mean that the magnetic field of the
EFR is affected by the preexisting magnetic environment surrounding
the EFR and that the emerging magnetic loops are deformed before or
at the time they reach the photospheric level.
Title: Balloon-borne hard x-ray spectrometer for flare observations
Authors: Kobayashi, Ken; Tsuneta, Saku; Tamura, Tomonori; Kumagai,
Kazuyoshi; Katsukawa, Yukio; Kubo, Masahito; Yamagami, Takamasa;
Saito, Yoshitaka
Bibcode: 2003SPIE.4851.1009K
Altcode:
We present the design and initial flight results of a balloon-borne
hard X-ray detector system for observing high-resolution spectra of
solar flares. The instrument is designed to achieve a 3 keV energy
resolution over the energy range of 15-120 keV. The instrument uses
sixteen 10×10×0.5mm cadmium telluride (CdTe) detectors with indium
electrodes that act as Schottky barriers. Pre-flight tests confirmed
that all detectors exceeded the target 3 keV resolution. The detector
system is designed to optimize radiative cooling in order to achieve
the operating temperature of 0°C without refrigeration mechanisms. The
first flight took place on August 29, 2001 and while no major flares
were observed, the instrument operation was verified and a detector
temperature of -13° C was achieved. The second flight took place on
May 24, 1974 and during the 8 hours of level flight at an altitude of
41km, we succeeded in observing a class M1.1 solar flare.
Title: TRACE Observation of an Arcade Flare Showing Evidence
Supporting Quadruple Magnetic Source Model for Arcade Flares
Authors: Uchida, Yutaka; Title, Alan; Kubo, Masahito; Tanaka, Tomohiro;
Morita, Satoshi; Hirose, Shigenobu
Bibcode: 2003PASJ...55..305U
Altcode:
The result of analyses of an arcade flare on 1999 July 19, observed by
the Satellite TRACE, is reported, and the significance of the following
findings is stressed. It is clearly seen that four magnetic regions of
alternating polarities [named A(+), B(-), C(+), and D(-) from the East
in the flaring region] are involved in this arcade flare event in an
essential way. The high structure covering the triangular region between
A and the northern part of D disappears when the dark filament lying
between B and C erupts. The X-ray arcade is formed only between B and
C. The overlying structure connecting regions A and the northern part of
D disappears and the entire region is involved in the flare. Low-lying
loops connect the inner sources to the outer sources. The field lines
from regions B to A and C to D are not much affected by the eruption
of the dark filament, itself, but the loops near the upper surfaces
of the closed loop regions are clearly seen to move toward each other
(from both sides to the central line) as the arcade flare progresses
between the inner pair, B and C; some of them appear to be converted
into a flare arcade. The observed behavior can best be understood in
terms of the quadruple magnetic source model advocated by one of the
authors (YU). The long-conceived ``reclosing of once opened bipolar
magnetic arcade'' models by the rising dark filament (called CSHKP
model) find it difficult to explain this.
Title: Development of the Solar-B spacecraft
Authors: Tsuneta, Saku; Ichimoto, Kiyoshi; Suematsu, Yoshinori;
Shimizu, Toshifumi; Hara, Hirohisa; Kano, Ryohei; Nagata, Shin'ichi;
Tamura, Tomonori; Nakagiri, Masao; Noguchi, Motokazu; Kato, Yoshihiro;
Watanabe, Tetsuya; Hanaoka, Yoichiro; Sawa, Masaki; Otsubo, Masashi;
Kosugi, Takeo; Yamada, Takahiro; Sakao, Taro; Matsuzaki, Keiichi;
Minesugi, Kenji; Onishi, Akira; Katsukawa, Yukio; Kobayashi, Ken;
Kubo, Masahito
Bibcode: 2003naoj.book....3T
Altcode:
No abstract at ADS
Title: Development of Solar-B solar optical telescope
Authors: Suematsu, Yoshinori; Ichimoto, Kiyoshi; Shimizu, Toshifumi;
Nagata, Shin'ichi; Tamura, Tomonori; Tsuneta, Saku; Noguchi, Motokazu;
Kato, Yoshihiro; Nakagiri, Masao; Otsubo, Masashi; Hanaoka, Yoichiro;
Katsukawa, Yukio; Kobayashi, Ken; Kubo, Masahito
Bibcode: 2003naoj.book....5S
Altcode:
No abstract at ADS
Title: Observation of solar flare hard x-ray spectra using CdTe
detectors
Authors: Kobayashi, K.; Tsuneta, S.; Tamura, T.; Kumagai, K.;
Katsukawa, Y.; Kubo, M.; Sakamoto, Y.; Yamagami, T.; Saito, Y.;
Mori, K.
Bibcode: 2002cosp...34E1971K
Altcode: 2002cosp.meetE1971K
We present the design and flight results of a balloon-borne hard
X-ray detector system for observing high-resolution spectra of solar
flares. The instrument is designed to achieve a 3 keV energy resolution
over the energy range of 15-120 keV. The instrument uses sixteen 10 ×
10 × 0.5 mm cadmium telluride (CdTe) detectors with indium electrodes
that act as Schottky barriers to minimize leak current and allow a high
bias voltage. Pre-flight tests confirmed that all detectors exceeded
the target 3 keV resolution. The pressurized detector vessel uses
a low-density (0.1 g/cm^2) CFRP/Rohacell window. The detectors are
passively shielded by 2 mm of lead, and field of view is constrained
with a graded-Z collimator. The vertical angle of the detectors are
fixed at 45 degrees, and the azimuth angle of the entire gondola
is controlled using a signal from a sun position sensor. Specially
developed electronics accumulate a 128 channel spectrum for each
detector, which is read through telemetry every 0.54 seconds. These
detectors need to be cooled down to 0 degrees C for optimal performance;
due to weight constraints this was achieved purely by radiative cooling,
using the detector enclosure surface as a radiator and by placing
shields that minimize radiative heat input from the sun and earth while
maximizing heat loss to the sky. The first flight of the instrument
took place on August 29, 2001 and while no major flares were observed,
we succeeded in detecting a small brightening (microflare). Detector
temperature of -13 degrees C was achieved, and all systems performed
as expected. The instrument was recovered successfully after the flight
and a second flight is planned for May 2002.
Title: The Dynamics of Coronal Holes as Determined From X-ray Synoptic
Maps Derived From SXT Imagery
Authors: Slater, G. L.; Linford, G. A.; Strong, K. T.; Acton, L. W.;
Tsuneta, S.; Hara, H.; Takahashi, T.; Hiei, H.; Kubo, M.; Harvey,
K.; Bornmann, P.; McIntosh, P. S.; Sime, D.; Watari, S.
Bibcode: 1993BAAS...25.1179S
Altcode:
No abstract at ADS
Title: Perfect Fluids Expanding with Both Vorticity and Shear
Authors: Kubo, M.
Bibcode: 1978PASJ...30..327K
Altcode:
A general theory of perfect fluids expanding with both the vorticity and
the shear is formulated. The anisotropy is divided into the expansion
anisotropy and the expansion-free anisotropy. Whether a model is
vorticity-dominant or shear-dominant depends on the sign of the
expansion-free anisotropy. The propagation equations of the expansion
anisotropy and the expansion-free anisotropy are derived to obtain the
generalized Friedmann equation. The expansion anisotropy interacts with
the expansion-free anisotropy by means of the interaction residual which
is one of the residual terms appearing in the propagation equations. The
expansion anisotropy increases the expansion, whereas the expansion-free
anisotropy decreases the expansion. Key words: Expanding universes;
Newtonian cosmology; Rotating universes; Perfect fluids.
Title: Expanding universes with shear.
Authors: Kubo, M.
Bibcode: 1975PASJ...27..111K
Altcode:
The classification and the evolution of expanding universes
with shear but without rotation and containing dustlike matter
are examined taking the cosmological constant into account. We
assume the isotropy of the Gaussian curvature in the hypersurface
orthogonal to the 4-velocity. Eight types of evolution-curves are
found on the parameter diagram constructed by the density parameter
and the anisotropy parameter. Monotonic models of the first kind and
oscillating models are divided into three or four subclasses by means
of their evolutionary characteristics, respectively.
Title: Evolution and Age of Anisotropic Cosmological Models with
Cosmological Constant
Authors: Kubo, M.
Bibcode: 1974PASJ...26..355K
Altcode:
The evolution and the age of anisotropic cosmological models with
cosmological constant containing dustlike matter are examined by means
of the density parameter sigma and the anisotropy parameter alpha. It
is shown that such models evolve from an anisotropic empty model
which remains fixed at a point (0,1/2) on the sigma, alpha plane as
the cosmic time elapses. The effect of anisotropy on the age of these
models is also discussed.
Title: Classification of uniform cosmological models.
Authors: Kubo, M.
Bibcode: 1972SRToh..55....1K
Altcode:
No abstract at ADS
Title: Evolution of uniform cosmological models containing both
matter and radiation.
Authors: Kubo, M.
Bibcode: 1971SRToh..54..113K
Altcode:
No abstract at ADS
Title: Classification of uniform cosmological models containing both
matter and radiation.
Authors: Kubo, M.
Bibcode: 1970SRToh..53..103K
Altcode:
No abstract at ADS