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Author name code: kuhn
ADS astronomy entries on 2022-09-14
author:"Kuhn, Jeffrey Richard"
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Title: The National Science Foundation's Daniel K. Inouye Solar
Telescope — Status Update
Authors: Rimmele, T.; Woeger, F.; Tritschler, A.; Casini, R.; de Wijn,
A.; Fehlmann, A.; Harrington, D.; Jaeggli, S.; Anan, T.; Beck, C.;
Cauzzi, G.; Schad, T.; Criscuoli, S.; Davey, A.; Lin, H.; Kuhn, J.;
Rast, M.; Goode, P.; Knoelker, M.; Rosner, R.; von der Luehe, O.;
Mathioudakis, M.; Dkist Team
2021AAS...23810601R Altcode:
The National Science Foundation's 4m Daniel K. Inouye Solar Telescope
(DKIST) on Haleakala, Maui is now the largest solar telescope in the
world. DKIST's superb resolution and polarimetric sensitivity will
enable astronomers to unravel many of the mysteries the Sun presents,
including the origin of solar magnetism, the mechanisms of coronal
heating and drivers of flares and coronal mass ejections. Five
instruments, four of which provide highly sensitive measurements
of solar magnetic fields, including the illusive magnetic field of
the faint solar corona. The DKIST instruments will produce large and
complex data sets, which will be distributed through the NSO/DKIST Data
Center. DKIST has achieved first engineering solar light in December
of 2019. Due to COVID the start of the operations commissioning phase
is delayed and is now expected for fall of 2021. We present a status
update for the construction effort and progress with the operations
commissioning phase.
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Title: DKIST First-light Instrumentation
Authors: Woeger, F.; Rimmele, T.; Casini, R.; von der Luehe, O.; Lin,
H.; Kuhn, J.; Dkist Team
2021AAS...23810602W Altcode:
The NSF's Daniel K. Inouye Solar Telescope's (DKIST) four meter aperture
and state-of-the-art wavefront correction system and instrumentation
will facilitate new insights into the complexities of the solar
atmosphere. We will describe the details and status of the diverse
first light instruments, including the high order adaptive optics
system, that are being commissioned: The Visible Spectro-Polarimeter
(ViSP), the Visible Broadband Imager (VBI), the Visible Tunable Filter
(VTF), the Diffraction-Limited Spectro-Polarimeter (DL-NIRSP) and the
Cryogenic Spectro-Polarimeter (Cryo-NIRSP). We will present first data
demonstrating the telescope's instrument systems performance.
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Title: Critical Science Plan for the Daniel K. Inouye Solar Telescope
(DKIST)
Authors: Rast, Mark P.; Bello González, Nazaret; Bellot Rubio,
Luis; Cao, Wenda; Cauzzi, Gianna; Deluca, Edward; de Pontieu, Bart;
Fletcher, Lyndsay; Gibson, Sarah E.; Judge, Philip G.; Katsukawa,
Yukio; Kazachenko, Maria D.; Khomenko, Elena; Landi, Enrico; Martínez
Pillet, Valentín; Petrie, Gordon J. D.; Qiu, Jiong; Rachmeler,
Laurel A.; Rempel, Matthias; Schmidt, Wolfgang; Scullion, Eamon; Sun,
Xudong; Welsch, Brian T.; Andretta, Vincenzo; Antolin, Patrick; Ayres,
Thomas R.; Balasubramaniam, K. S.; Ballai, Istvan; Berger, Thomas E.;
Bradshaw, Stephen J.; Campbell, Ryan J.; Carlsson, Mats; Casini,
Roberto; Centeno, Rebecca; Cranmer, Steven R.; Criscuoli, Serena;
Deforest, Craig; Deng, Yuanyong; Erdélyi, Robertus; Fedun, Viktor;
Fischer, Catherine E.; González Manrique, Sergio J.; Hahn, Michael;
Harra, Louise; Henriques, Vasco M. J.; Hurlburt, Neal E.; Jaeggli,
Sarah; Jafarzadeh, Shahin; Jain, Rekha; Jefferies, Stuart M.; Keys,
Peter H.; Kowalski, Adam F.; Kuckein, Christoph; Kuhn, Jeffrey R.;
Kuridze, David; Liu, Jiajia; Liu, Wei; Longcope, Dana; Mathioudakis,
Mihalis; McAteer, R. T. James; McIntosh, Scott W.; McKenzie, David
E.; Miralles, Mari Paz; Morton, Richard J.; Muglach, Karin; Nelson,
Chris J.; Panesar, Navdeep K.; Parenti, Susanna; Parnell, Clare E.;
Poduval, Bala; Reardon, Kevin P.; Reep, Jeffrey W.; Schad, Thomas A.;
Schmit, Donald; Sharma, Rahul; Socas-Navarro, Hector; Srivastava,
Abhishek K.; Sterling, Alphonse C.; Suematsu, Yoshinori; Tarr, Lucas
A.; Tiwari, Sanjiv; Tritschler, Alexandra; Verth, Gary; Vourlidas,
Angelos; Wang, Haimin; Wang, Yi-Ming; NSO and DKIST Project; DKIST
Instrument Scientists; DKIST Science Working Group; DKIST Critical
Science Plan Community
2021SoPh..296...70R Altcode: 2020arXiv200808203R
The National Science Foundation's Daniel K. Inouye Solar Telescope
(DKIST) will revolutionize our ability to measure, understand,
and model the basic physical processes that control the structure
and dynamics of the Sun and its atmosphere. The first-light DKIST
images, released publicly on 29 January 2020, only hint at the
extraordinary capabilities that will accompany full commissioning of
the five facility instruments. With this Critical Science Plan (CSP)
we attempt to anticipate some of what those capabilities will enable,
providing a snapshot of some of the scientific pursuits that the DKIST
hopes to engage as start-of-operations nears. The work builds on the
combined contributions of the DKIST Science Working Group (SWG) and
CSP Community members, who generously shared their experiences, plans,
knowledge, and dreams. Discussion is primarily focused on those issues
to which DKIST will uniquely contribute.
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Title: Using long baseline radial velocities and direct imaging to
make 13-sigma dynamical mass measurements for the components of the
HD 104304 stellar binary.
Authors: Nagpal, V.; Blunt, S.; Howard, A.; Hirsch, L.; Liu, M.;
Isaacson, H.; Morales, F.; Kuhn, J.
2021AAS...23753003N Altcode:
Combining direct imaging astrometry and long-baseline radial
velocity (RV) measurements of stellar binaries can provide precise
constraints on their 3D orbits and yield dynamical masses for both
components. We applied the combination of these methods to study
HD104304, a binary system with a decades-long orbit containing a G8IV
subgiant and a recently-discovered M dwarf companion. Using radial
velocities collected over a timespan of two decades by Keck/HIRES and
astrometry calculated from adaptive optics images taken by Keck/NIRC2,
we explored models to jointly fit the astrometric orbital motion and RV
trend. Previous studies of this system (Howard & Fulton, 2016) were
unable to distinguish between two and three body solutions using RVs
alone. However, we are able to break this degeneracy by incorporating
images into the fit. We make 13-sigma dynamical mass measurements of
the primary and secondary, and find that a slightly eccentric solution
(e=0.4) is required. However, the dynamical mass we measure for the
primary (~1.8 solar masses) is significantly higher than its well
constrained spectroscopic mass of 1.02 solar masses. This hints at
the need for a three-body solution to accurately model the observed
trend in the HD 104304 system.
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Title: The Daniel K. Inouye Solar Telescope - Observatory Overview
Authors: Rimmele, Thomas R.; Warner, Mark; Keil, Stephen L.; Goode,
Philip R.; Knölker, Michael; Kuhn, Jeffrey R.; Rosner, Robert R.;
McMullin, Joseph P.; Casini, Roberto; Lin, Haosheng; Wöger, Friedrich;
von der Lühe, Oskar; Tritschler, Alexandra; Davey, Alisdair; de Wijn,
Alfred; Elmore, David F.; Fehlmann, André; Harrington, David M.;
Jaeggli, Sarah A.; Rast, Mark P.; Schad, Thomas A.; Schmidt, Wolfgang;
Mathioudakis, Mihalis; Mickey, Donald L.; Anan, Tetsu; Beck, Christian;
Marshall, Heather K.; Jeffers, Paul F.; Oschmann, Jacobus M.; Beard,
Andrew; Berst, David C.; Cowan, Bruce A.; Craig, Simon C.; Cross,
Eric; Cummings, Bryan K.; Donnelly, Colleen; de Vanssay, Jean-Benoit;
Eigenbrot, Arthur D.; Ferayorni, Andrew; Foster, Christopher; Galapon,
Chriselle Ann; Gedrites, Christopher; Gonzales, Kerry; Goodrich, Bret
D.; Gregory, Brian S.; Guzman, Stephanie S.; Guzzo, Stephen; Hegwer,
Steve; Hubbard, Robert P.; Hubbard, John R.; Johansson, Erik M.;
Johnson, Luke C.; Liang, Chen; Liang, Mary; McQuillen, Isaac; Mayer,
Christopher; Newman, Karl; Onodera, Brialyn; Phelps, LeEllen; Puentes,
Myles M.; Richards, Christopher; Rimmele, Lukas M.; Sekulic, Predrag;
Shimko, Stephan R.; Simison, Brett E.; Smith, Brett; Starman, Erik;
Sueoka, Stacey R.; Summers, Richard T.; Szabo, Aimee; Szabo, Louis;
Wampler, Stephen B.; Williams, Timothy R.; White, Charles
2020SoPh..295..172R Altcode:
We present an overview of the National Science Foundation's Daniel
K. Inouye Solar Telescope (DKIST), its instruments, and support
facilities. The 4 m aperture DKIST provides the highest-resolution
observations of the Sun ever achieved. The large aperture of
DKIST combined with state-of-the-art instrumentation provide the
sensitivity to measure the vector magnetic field in the chromosphere
and in the faint corona, i.e. for the first time with DKIST we will
be able to measure and study the most important free-energy source
in the outer solar atmosphere - the coronal magnetic field. Over its
operational lifetime DKIST will advance our knowledge of fundamental
astronomical processes, including highly dynamic solar eruptions
that are at the source of space-weather events that impact our
technological society. Design and construction of DKIST took over two
decades. DKIST implements a fast (f/2), off-axis Gregorian optical
design. The maximum available field-of-view is 5 arcmin. A complex
thermal-control system was implemented in order to remove at prime
focus the majority of the 13 kW collected by the primary mirror and
to keep optical surfaces and structures at ambient temperature, thus
avoiding self-induced local seeing. A high-order adaptive-optics
system with 1600 actuators corrects atmospheric seeing enabling
diffraction limited imaging and spectroscopy. Five instruments, four
of which are polarimeters, provide powerful diagnostic capability
over a broad wavelength range covering the visible, near-infrared,
and mid-infrared spectrum. New polarization-calibration strategies
were developed to achieve the stringent polarization accuracy
requirement of 5×10<SUP>−4</SUP>. Instruments can be combined and
operated simultaneously in order to obtain a maximum of observational
information. Observing time on DKIST is allocated through an open,
merit-based proposal process. DKIST will be operated primarily in
"service mode" and is expected to on average produce 3 PB of raw
data per year. A newly developed data center located at the NSO
Headquarters in Boulder will initially serve fully calibrated data to
the international users community. Higher-level data products, such as
physical parameters obtained from inversions of spectro-polarimetric
data will be added as resources allow.
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Title: High dynamic-range observation using a 1.8-m off-axis telescope
PLANETS: feasibility study and telescope design
Authors: Kagitani, Masato; Sakanoi, Takeshi; Kasaba, Yasumasa;
Hirahara, Yasuhiro; Kurita, Mikio; Kuhn, Jeffrey R.; Berdyugina,
Svetlana V.; Emilio, Marcelo
2020SPIE11445E..43K Altcode:
PLANETS will be a 1.8-m off-axis telescope combined with contrast
enhancement techniques, enabling us to observe faint emissions in
the vicinity of bright objects. This "high dynamic-range" capability
is largely dependent upon precision of telescope optics as well as
atmospheric distortion. We present feasibility study of monitoring
water plumes on Europa, neutral torus close to Enceladus, and
ionosphere on Mars using PLANETS telescope. To test feasibility of
high dynamic-range observation under actual conditions of wavefront
error, we modeled propagation of light though the system based on
Fraunhofer calculation taking into account for wavefront error made by
atmospheric distortion and by primary mirror figure error. Then point
spread function is calculated for several cases of figure errors under
use of adaptive optics. The modeling result predicts that the moderate
or high-precision primary mirror is mandatory to accomplish the high
dynamic-range observation. We also present the latest design of PLANETS,
especially focus on the support structures of primary mirror. We employ
36-point whiffletrees with 33 warping harnesses for axial support, and
24-point Schwesinger support for lateral support. The active support
system is expected to reduce pre-polished RMS error from 1.51 μm
to 0.66 μm corresponding to 70% reduction in total volume of final
polish. The laboratory experiment using one third part of prototype
whiffletrees shows supporting force RMS repeatability < 0.005 kgf,
and drive hysteresis < 0.7% of load range, which are precise enough
to control or to keep the primary mirror figure.
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Title: Advanced 3D-printed EAP actuator applied to high precision
large optical-quality surface fabrication: first results
Authors: Thetpraphi, K.; Moretto, G.; Kuhn, J. R.; Cottinet, P. J.;
Le, M. Q.; Audigier, D.; Petit, L.; Capsal, J. F.
2020SPIE11375E..1XT Altcode:
LiveMetaOptics presented the Exo-life finder (ELF) telescope combined
with the hybrid dynamic structure of live and light active mirror named
as "Live-mirror". Recently we reported the idea of active optical
surface correction using the advantage of an electromechanical
stimulator to deform mirror surface in a significant correction
scale. An effort to develop a conventional electroactive polymer
(EAP) actuator through Live-mirror application has been taken the new
approach, assembling EAP actuator via additive manufacturing or 3D
printing technology. The approach of next-generation mirror leaned on
3D printing technological advancement is able to unlock the principles
of a potentially new actuator manufacturing technique. Full 3D print
of modified EAP was formulated with plasticized terpolymer for an
active layer and terpolymer/CB composite for printed electrodes. Though
rudimentary of electroactive polymer, the full-printed actuator could
transfer its transversal stress or shear force to shape the mirror
surface under low applied electric fields. We described here as well
creating multilayer structures with capabilities well beyond those
of the individual actuator components. Our various configurations of
printed actuators could achieve glass surface deformation in a range of
50 nm to 2 µm considering the maximum glass deformation. As a result
of material modification coupled with 3D printing technology, we can
increase productivity while enabling a mass and cost reduction and an
increase of the parts functionality in terms of the real application.
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Title: SPHERE+: Imaging young Jupiters down to the snowline
Authors: Boccaletti, A.; Chauvin, G.; Mouillet, D.; Absil, O.;
Allard, F.; Antoniucci, S.; Augereau, J. -C.; Barge, P.; Baruffolo,
A.; Baudino, J. -L.; Baudoz, P.; Beaulieu, M.; Benisty, M.; Beuzit,
J. -L.; Bianco, A.; Biller, B.; Bonavita, B.; Bonnefoy, M.; Bos, S.;
Bouret, J. -C.; Brandner, W.; Buchschache, N.; Carry, B.; Cantalloube,
F.; Cascone, E.; Carlotti, A.; Charnay, B.; Chiavassa, A.; Choquet,
E.; Clenet, Y.; Crida, A.; De Boer, J.; De Caprio, V.; Desidera, S.;
Desert, J. -M.; Delisle, J. -B.; Delorme, P.; Dohlen, K.; Doelman,
D.; Dominik, C.; Orazi, V. D; Dougados, C.; Doute, S.; Fedele, D.;
Feldt, M.; Ferreira, F.; Fontanive, C.; Fusco, T.; Galicher, R.;
Garufi, A.; Gendron, E.; Ghedina, A.; Ginski, C.; Gonzalez, J. -F.;
Gratadour, D.; Gratton, R.; Guillot, T.; Haffert, S.; Hagelberg, J.;
Henning, T.; Huby, E.; Janson, M.; Kamp, I.; Keller, C.; Kenworthy,
M.; Kervella, P.; Kral, Q.; Kuhn, J.; Lagadec, E.; Laibe, G.; Langlois,
M.; Lagrange, A. -M.; Launhardt, R.; Leboulleux, L.; Le Coroller, H.;
Li Causi, G.; Loupias, M.; Maire, A. L.; Marleau, G.; Martinache,
F.; Martinez, P.; Mary, D.; Mattioli, M.; Mazoyer, J.; Meheut, H.;
Menard, F.; Mesa, D.; Meunier, N.; Miguel, Y.; Milli, J.; Min, M.;
Molliere, P.; Mordasini, C.; Moretto, G.; Mugnier, L.; Muro Arena,
G.; Nardetto, N.; Diaye, M. N; Nesvadba, N.; Pedichini, F.; Pinilla,
P.; Por, E.; Potier, A.; Quanz, S.; Rameau, J.; Roelfsema, R.; Rouan,
D.; Rigliaco, E.; Salasnich, B.; Samland, M.; Sauvage, J. -F.; Schmid,
H. -M.; Segransan, D.; Snellen, I.; Snik, F.; Soulez, F.; Stadler, E.;
Stam, D.; Tallon, M.; Thebault, P.; Thiebaut, E.; Tschudi, C.; Udry,
S.; van Holstein, R.; Vernazza, P.; Vidal, F.; Vigan, A.; Waters,
R.; Wildi, F.; Willson, M.; Zanutta, A.; Zavagno, A.; Zurlo, A.
2020arXiv200305714B Altcode:
SPHERE (Beuzit et al,. 2019) has now been in operation at the VLT for
more than 5 years, demonstrating a high level of performance. SPHERE
has produced outstanding results using a variety of operating modes,
primarily in the field of direct imaging of exoplanetary systems,
focusing on exoplanets as point sources and circumstellar disks as
extended objects. The achievements obtained thus far with SPHERE
(~200 refereed publications) in different areas (exoplanets, disks,
solar system, stellar physics...) have motivated a large consortium
to propose an even more ambitious set of science cases, and its
corresponding technical implementation in the form of an upgrade. The
SPHERE+ project capitalizes on the expertise and lessons learned
from SPHERE to push high contrast imaging performance to its limits
on the VLT 8m-telescope. The scientific program of SPHERE+ described
in this document will open a new and compelling scientific window for
the upcoming decade in strong synergy with ground-based facilities
(VLT/I, ELT, ALMA, and SKA) and space missions (Gaia, JWST, PLATO and
WFIRST). While SPHERE has sampled the outer parts of planetary systems
beyond a few tens of AU, SPHERE+ will dig into the inner regions
around stars to reveal and characterize by mean of spectroscopy the
giant planet population down to the snow line. Building on SPHERE's
scientific heritage and resounding success, SPHERE+ will be a dedicated
survey instrument which will strengthen the leadership of ESO and the
European community in the very competitive field of direct imaging
of exoplanetary systems. With enhanced capabilities, it will enable
an even broader diversity of science cases including the study of the
solar system, the birth and death of stars and the exploration of the
inner regions of active galactic nuclei.
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Title: Surface Imaging of Proxima b and Other Exoplanets: Albedo Maps,
Biosignatures, and Technosignatures
Authors: Berdyugina, S. V.; Kuhn, J. R.
2019AJ....158..246B Altcode:
Seeing oceans, continents, quasi-static weather, and other surface
features on exoplanets may allow for detecting and characterizing life
outside the solar system. The Proxima b exoplanet resides within the
stellar habitable zone, possibly allowing for liquid water on its
surface, as on Earth. However, even the largest planned telescopes
will not be able to resolve its surface features directly. Here we
demonstrate an inversion technique to indirectly image exoplanet
surfaces using observed unresolved reflected light variations
over the course of the exoplanet’s orbital and axial rotation:
ExoPlanet Surface Imaging (EPSI). We show that the reflected light curve
contains enough information to detect both longitudinal and latitudinal
structures and to map exoplanet surface features. We demonstrate this
using examples of solar system planets and moons, as well as simulated
planets with Earth-like life and artificial structures. We also describe
how it is possible to infer the planet and orbit geometry from light
curves. Then, we show how albedo maps of Proxima b can be successfully
reconstructed for tidally locked, resonance, and unlocked axial and
orbital rotation. Such albedo maps obtained in different wavelength
passbands can provide “photographic” views of distant exoplanets. We
estimate the signal-to-noise ratio necessary for successful inversions
and analyze telescope and detector requirements necessary for the first
surface image reconstructions of Proxima b and other nearby exoplanets
using EPSI. This is a significant challenge, but the success of such
measurements depends heavily on large-aperture diffraction-limited
telescope performance—a feat that may be achieved on the ground
before it is in space.
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Title: State of the Profession Considerations for Laboratory
Astrophysics
Authors: Savin, Daniel Wolf; Babb, James F.; Barklem, Paul; Bellan,
Paul M.; Betancourt-Martinez, Gabriele; Blum, Jürgen; Boersma,
Christiaan; Boryta, Mark D.; Brisset, Julie; Brogan, Crystal; Cami,
Jan; Caselli, Paola; Chutjian, Ara; Corrales, Lia; Crabtree, Kyle;
Dominguez, Gerardo; Federman, Steven R.; Fontes, Christopher J.;
Freedman, Richard; Gavilan-Marin, Lisseth; Gibson, Brad; Golub, Leon;
Gorczyca, Thomas W.; Hahn, Michael; Hartmann, Dieter; Hörst, Sarah M.;
Hudson, Reggie L.; Ji, Hantao; Kreckel, Holger; Kuhn, Jeffrey; Lawler,
James E.; Lee, Timothy J.; Leutenegger, Maurice A.; Mancini, Roberto;
Marler, Joan P.; Mashonkina, Lyudmila I.; McCarthy, Michael C.;
McCoustra, Martin; McGuire, Brett A.; Milam, Stefanie N.; Montgomery,
Mike; Murphy, Nicholas A.; Nave, Gillian; Nelson, Robert M.; Nollett,
Kenneth M.; Norton, Aimee A.; Novotný, Oldřich; Papol, Anthony;
Raymond, John C.; Salama, Farid; Sciamma-O'Brien, Ella M.; Smith,
Randall; Sosolik, Chad; Sousa-Silva, Clara; Spyrou, Artemis; Stancil,
Phillip C.; Sung, Keeyoon; Tennyson, Jonathan; Timmes, Frank; Trimble,
Virginia L.; Venot, Olivia; Wahlgren, Glenn; Wargelin, Bradford J.;
Winget, Don; Wood, Michael P.
2019BAAS...51g...7S Altcode: 2019astro2020U...7S
Astrophysics advances, in part, through laboratory astrophysics studies
of the underlying processes controlling the observed properties of
the Cosmos. These studies encompass both theoretical and experimental
research. Robust support for laboratory astrophysics is critically
needed to maximize the scientific return of astronomical observations.
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Title: Coronagraphic Observations of Si X λ14301 and Fe XIII λ10747
Linearly Polarized Spectra Using the SOLARC Telescope
Authors: Dima, Gabriel I.; Kuhn, Jeffrey R.; Schad, Thomas A.
2019ApJ...877..144D Altcode:
The forbidden Si X emission line at 14301 Å has been identified
as a potentially valuable polarized diagnostic for solar coronal
magnetic fields; however, the only polarized Si X measurements
achieved to date have been during eclipses and at comparatively low
spatial and spectral resolution. Here we report spectropolarimetric
observations of both the Si X 14301 Å and more well-established Fe
XIII 10747 Å coronal lines acquired with the 0.45 m aperture SOLARC
coronagraph atop Haleakalā. Using its fiber-based integral field
spectropolarimeter, we derive observations sampled at radial intervals
of 0.05 {R}<SUB>⊙ </SUB> (i.e., ∼50″) with a spectral resolving
power of ≈36,000. Results for both lines, which represent averages
over different active and nonactive regions of the corona, indicate a
relatively flat radial variation for the line widths and line centers
and a factor of ≈2-3 decrease in polarized brightness between 1.05
and 1.45 {R}<SUB>⊙ </SUB>. Averaging over all the measurements the
mean and standard deviations of line properties for Si X 14301 Å and
Fe XIII 10747 Å are, respectively, FWHM of 3.0 ± 0.4 Å and 1.6 ±
0.1 Å, line-integrated polarized brightness of 0.07 ± 0.03 and 0.3
± 0.3 erg s<SUP>-2</SUP> cm<SUP>-2</SUP> sr<SUP>-1</SUP>, where the
uncertainty quoted reflects a large sample variance, and line center
wavelengths 14300.7 ± 0.2 Å and 10746.3 ± 0.1 Å. The polarized
brightness for both lines may be underestimated by up to a factor of
5 due to limitations in the photometric calibration. When accounting
for this uncertainty we find consistency between our observations
and previous measurements of the two lines as well as theoretical
calculations and affirm the potential of the Si X line as a polarized
diagnostic of the solar corona.
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Title: Polarimetric observations of the SiX and Fe XIII infrared
coronal emission lines using the SOLARC telescope
Authors: Dima, Gabriel; Kuhn, Jeffrey Richard; Schad, Thomas A.
2019AAS...23411704D Altcode:
The forbidden Si X emission line at 14301 Å has been identified as a
potentially valuable polarized diagnostic for solar coronal magnetic
fields; however, the only polarized Si X measurements achieved to
date have been during eclipses and at comparatively low spatial and
spectral resolution. Here we report spectropolarimetric observations
of both the Si X 14301 Å and more well-established FeXIII 10747 Å
coronal lines acquired with the 0.45 m aperture SOLARC coronagraph
atop Haleakala. Results for both lines, which represent averages over
different active and non-active regions of the corona, indicate a
relatively flat radial variation for the line widths and line centers
and a factor of 2-3 decrease in polarized brightness between 1.05 and
1.45 R<SUB>⊙</SUB>. Averaging over all the measurements the mean
and standard deviations of line properties for Si X 14301 Å and Fe
XIII 10747 Å are respectively: FWHM of 3.0±0.4 Å and 1.6±0.1,
line-integrated polarized brightness of 0.07±0.03 and 0.3±0.3 erg
s<SUP>-2</SUP> cm<SUP>-2</SUP> sr<SUP>-1</SUP> where the uncertainty
quoted reflects a large sample variance, and line center wavelengths
14300.7±0.2 Å and 10746.3±0.1 Å. The polarized brightness for both
lines may be underestimated by up to a factor of 5 due to limitations
in the photometric calibration. When accounting for this uncertainty
we find consistency between our observations and previous measurements
of the two lines as well as theoretical calculations and affirm the
potential of the Si X line as a polarized diagnostic of the solar
corona.
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Title: Hanle Coronal Magnetometry Using Permitted He I 1083 nm and
Forbidden Si X 1430 nm IR Emission Lines
Authors: Dima, G. I.; Kuhn, J. R.; Berdyugina, S. V.
2019ASPC..526..199D Altcode:
With a model of the coronal Hanle effect, and by measuring the linear
polarization of permitted and forbidden lines, it is possible to
determine the magnetic field in the emission region of the considered
lines. This technique may be applicable in the corona because of the
discovery of faint He I emission, possibly due to a non-equilibrium
population of He I atoms originating on coronal dust grains. He I 1083
nm lies in the unsaturated Hanle regime for field strengths below 8
G, so that the polarization amplitude and orientation are sensitive
to both the orientation and strength of the magnetic field. To break
this degeneracy we can use one of several coronal infrared forbidden
lines, like Fe XIII 1075 nm or Si X 1430 nm. These forbidden lines
are sensitive to different coronal temperature regimes, and provide
additional constraints on the orientation of the magnetic field. We
discuss magnetic field uncertainties inherent to this measurement
technique, and present the first polarized measurements of the Si X
1430 nm line, obtained using the SOLARC telescope on Haleakalā.
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Title: Astrophysical Science enabled by Laboratory Astrophysics
Studies in Atomic, Molecular, and Optical (AMO) Physics
Authors: Savin, Daniel Wolf; Babb, James F.; Bellan, Paul M.; Brogan,
Crystal; Cami, Jan; Caselli, Paola; Corrales, Lia; Dominguez, Gerardo;
Federman, Steven R.; Fontes, Chris J.; Freedman, Richard; Gibson,
Brad; Golub, Leon; Gorczyca, Thomas W.; Hahn, Michael; Hartmann,
Dieter; Hörst, Sarah M.; Hudson, Reggie L.; Kuhn, Jeffrey; Lawler,
James E.; Leutenegger, Maurice A.; Marler, Joan P.; McCarthy, Michael
C.; McGuire, Brett A.; Milam, Stefanie N.; Murphy, Nicholas A.; Nave,
Gillian; Norton, Aimee A.; Papol, Anthony; Raymond, John C.; Salama,
Farid; Sciamma-O'Brien, Ella M.; Smith, Randall; Sosolik, Chad;
Sousa-Silva, Clara; Stancil, Phillip C.; Timmes, Frank; Trimble,
Virginia L.; Wargelin, Bradford J.
2019BAAS...51c..96S Altcode: 2019astro2020T..96S
We highlight a few of the many astrophysical advances that will become
possible with advances in AMO laboratory astrophysics. This submission
supersedes the previous submission.
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Title: Measurements of Solar Oblateness during the SDO Mission
Authors: Bush, R. I.; Emilio, M.; Scholl, I.; Kuhn, J. R.; Sommers, J.
2018csc..confE...5B Altcode:
Beginning in April 2010, the Helioseismic and Magnetic Imager (HMI)
instrument on the Solar Dynamics Observatory (SDO) spacecraft
has been making periodic measurements of the solar shape. The
primary observations are 4096 by 4096 pixel full Sun images taken
in the continuum of the 617.3 nm Fe I absorption line in 4 linear
polarizations. It is necessary to determine the instrument optical
distortion in order to extract the solar shape from the full Sun
images. This is accomplished during a roll maneuver of the SDO
spacecraft in which the spacecraft is rotated 360 degrees around
the Sun-spacecraft line while taking a series of images at 32
uniformly spaced roll angles. Measurements of the solar oblateness
are typically obtained twice per year, and eighteen roll maneuvers
have been performed by the SDO spacecraft to date. Initially these
observations were taken in April and October from 2011 to 2014. During
the April 2015 roll, however, the spacecraft maneuver was aborted
due to a pointing anomaly. This error condition was identified, but
subsequent roll maneuvers were shifted to January and July of the
following years. The mean equator to pole radius difference over the
nine years of observations is 6.0 +/- 1.0 milli-arcseconds. The higher
order (hexadecapole) term is consistent with 0. The long term trend
of the solar oblateness does not show a correlation with the current
solar sunspot cycle. Details of the measurements and trending will
be discussed.
---------------------------------------------------------
Title: Perspectives on Astrophysics Based on Atomic, Molecular,
and Optical (AMO) Techniques
Authors: Savin, Daniel Wolf; Babb, James F.; Bellan, Paul M.; Brogan,
Crystal; Cami, Jan; Caselli, Paola; Corrales, Lia; Dominguez, Gerardo;
Federman, Steven R.; Fontes, Chris J.; Freedman, Richard; Gibson,
Brad; Golub, Leon; Gorczyca, Thomas W.; Hahn, Michael; Hörst, Sarah
M.; Hudson, Reggie L.; Kuhn, Jeffrey; Lawler, James E.; Leutenegger,
Maurice A.; Marler, Joan P.; McCarthy, Michael C.; McGuire, Brett A.;
Milam, Stefanie N.; Murphy, Nicholas A.; Nave, Gillian; Norton, Aimee
A.; Papol, Anthony; Raymond, John C.; Salama, Farid; Sciamma-O'Brien,
Ella M.; Smith, Randall; Sosolik, Chad; Sousa-Silva, Clara; Stancil,
Phillip C.; Timmes, Frank; Trimble, Virginia L.; Wargelin, Bradford J.
2018arXiv181106157S Altcode:
About two generations ago, a large part of AMO science was dominated by
experimental high energy collision studies and perturbative theoretical
methods. Since then, AMO science has undergone a transition and is now
dominated by quantum, ultracold, and ultrafast studies. But in the
process, the field has passed over the complexity that lies between
these two extremes. Most of the Universe resides in this intermediate
region. We put forward that the next frontier for AMO science is to
explore the AMO complexity that describes most of the Cosmos.
---------------------------------------------------------
Title: Review of high-contrast imaging systems for current and
future ground- and space-based telescopes I: coronagraph design
methods and optical performance metrics
Authors: Ruane, G.; Riggs, A.; Mazoyer, J.; Por, E. H.; N'Diaye,
M.; Huby, E.; Baudoz, P.; Galicher, R.; Douglas, E.; Knight, J.;
Carlomagno, B.; Fogarty, K.; Pueyo, L.; Zimmerman, N.; Absil, O.;
Beaulieu, M.; Cady, E.; Carlotti, A.; Doelman, D.; Guyon, O.; Haffert,
S.; Jewell, J.; Jovanovic, N.; Keller, C.; Kenworthy, M. A.; Kuhn, J.;
Miller, K.; Sirbu, D.; Snik, F.; Wallace, J. Kent; Wilby, M.; Ygouf, M.
2018SPIE10698E..2SR Altcode: 2018arXiv180707042R
The Optimal Optical Coronagraph (OOC) Workshop at the Lorentz Center
in September 2017 in Leiden, the Netherlands gathered a diverse group
of 25 researchers working on exoplanet instrumentation to stimulate
the emergence and sharing of new ideas. In this first installment of a
series of three papers summarizing the outcomes of the OOC workshop, we
present an overview of design methods and optical performance metrics
developed for coronagraph instruments. The design and optimization
of coronagraphs for future telescopes has progressed rapidly over the
past several years in the context of space mission studies for Exo-C,
WFIRST, HabEx, and LUVOIR as well as ground-based telescopes. Design
tools have been developed at several institutions to optimize a variety
of coronagraph mask types. We aim to give a broad overview of the
approaches used, examples of their utility, and provide the optimization
tools to the community. Though it is clear that the basic function
of coronagraphs is to suppress starlight while maintaining light
from off-axis sources, our community lacks a general set of standard
performance metrics that apply to both detecting and characterizing
exoplanets. The attendees of the OOC workshop agreed that it would
benefit our community to clearly define quantities for comparing the
performance of coronagraph designs and systems. Therefore, we also
present a set of metrics that may be applied to theoretical designs,
testbeds, and deployed instruments. We show how these quantities may
be used to easily relate the basic properties of the optical instrument
to the detection significance of the given point source in the presence
of realistic noise.
---------------------------------------------------------
Title: The Exo-Life Finder Telescope (ELF): design and beam synthesis
concepts
Authors: Kuhn, J. R.; Berdyugina, S. V.; Capsal, J. -F.; Gedig, M.;
Langlois, M.; Moretto, G.; Thetpraphi, K.
2018SPIE10700E..15K Altcode:
Currently planned massively segmented telescopes like the European
Extremely Large Telescope (EELT)1 or the Thirty Meter Telescope (TMT)2,
use "Keck-era" optics. Their mirror subapertures create a dynamically
rigid primary optical surface from 100's of 1m-scale few-cm thick
mirrors. We suggest that a dedicated telescope for distinguishing
reflected exoplanet light from its host star may not follow these
design principles. To reduce moving mass and telescope-scattered
light, a post-Keck era large telescope could use new technologies that
replace this opto-mechanical stiffness with massively parallel active
electro-optics and interferometric concepts. This opens the intriguing
possibility of building a dedicated ground-based exoplanet telescope
with an aperture of 20m at a cost-scale of $100M. This is a compelling
reason for exploring what we call "synthetic aperture" or "hybrid
optical telescopes." Even larger apertures that could be an order of
magnitude less costly per square meter than comparable Keck-like optics
are possible. Here we consider an optical system built from a relatively
"floppy" optical structure and scalable interferometrically phased,
moderate size (5m diameter), subapertures. This ExoLife Finder (ELF)
telescope is sensitive to optical biomarker signals and has the power to
map the surfaces of nearby M-dwarf exoplanets on subcontinental scales.
---------------------------------------------------------
Title: The Exo-Life Finder (ELF) telescope: New strategies for direct
detection of exoplanet biosignatures and technosignatures
Authors: Berdyugina, S. V.; Kuhn, J. R.; Langlois, M.; Moretto, G.;
Krissansen-Totton, J.; Catling, D.; Grenfell, J. L.; Santl-Temkiv,
T.; Finster, K.; Tarter, J.; Marchis, F.; Hargitai, H.; Apai, D.
2018SPIE10700E..4IB Altcode:
The Exo-Life Finder (ELF) will be an optical system with the
resolving power of a >=20m telescope optimized for characterizing
exoplanets and detecting exolife. It will allow for direct detection
of Earth-size planets in commonlyconsidered water-based habitable zones
(WHZ) of nearby stars and for generic exolife studies. Here we discuss
capabilities of the ELF to detect biosignatures and technosignatures in
exoplanetary atmospheres and on their surfaces in the visual and near
infrared. We evaluate sensitivity limits for mid- and low-resolution
spectral, photometric and polarimetric measurements, analyzed using
atmosphere models and light-curve inversions. In particular, we model
and estimate integration times required to detect O<SUB>2</SUB>,
O<SUB>3</SUB>, CO<SUB>2</SUB>, CH<SUB>4</SUB>, H<SUB>2</SUB>O and
other biosignature gases and habitability markers. Disequilibrium
biosignature pairs such as O<SUB>2</SUB>+CH<SUB>4</SUB> or
CO<SUB>2</SUB>+CH<SUB>4</SUB>-CO are also explored. Photosynthetic and
nonphotosynthetic pigments are other important biosignatures that ELF
will search for in atmospheres and on resolved surfaces of exoplanets,
in the form of bioaerosols and colonies of organisms. Finally, possible
artificial structures on exoplanet surfaces and in near-exoplanet space
can be detected. Practical instrument requirements are formulated
for detecting these spectral and structural biosignatures and
technosignatures. It is imperative that such a study is applied first
to characterize the nearest exoplanet Proxima b, then to search for
exo-Earths in the Alpha Cen A and B system and other near-Sun stars,
and finally to explore larger exoplanets around more distant stars.
---------------------------------------------------------
Title: Status of the Daniel K. Inouye Solar Telescope: unraveling
the mysteries the Sun.
Authors: Rimmele, Thomas R.; Martinez Pillet, Valentin; Goode, Philip
R.; Knoelker, Michael; Kuhn, Jeffrey Richard; Rosner, Robert; Casini,
Roberto; Lin, Haosheng; von der Luehe, Oskar; Woeger, Friedrich;
Tritschler, Alexandra; Fehlmann, Andre; Jaeggli, Sarah A.; Schmidt,
Wolfgang; De Wijn, Alfred; Rast, Mark; Harrington, David M.; Sueoka,
Stacey R.; Beck, Christian; Schad, Thomas A.; Warner, Mark; McMullin,
Joseph P.; Berukoff, Steven J.; Mathioudakis, Mihalis; DKIST Team
2018AAS...23231601R Altcode:
The 4m Daniel K. Inouye Solar Telescope (DKIST) currently under
construction on Haleakala, Maui will be the world’s largest solar
telescope. Designed to meet the needs of critical high resolution and
high sensitivity spectral and polarimetric observations of the sun,
this facility will perform key observations of our nearest star that
matters most to humankind. DKIST’s superb resolution and sensitivity
will enable astronomers to address many of the fundamental problems
in solar and stellar astrophysics, including the origin of stellar
magnetism, the mechanisms of coronal heating and drivers of the
solar wind, flares, coronal mass ejections and variability in solar
and stellar output. DKIST will also address basic research aspects of
Space Weather and help improve predictive capabilities. In combination
with synoptic observations and theoretical modeling DKIST will unravel
the many remaining mysteries of the Sun.The construction of DKIST is
progressing on schedule with 80% of the facility complete. Operations
are scheduled to begin early 2020. DKIST will replace the NSO
facilities on Kitt Peak and Sac Peak with a national facility with
worldwide unique capabilities. The design allows DKIST to operate as
a coronagraph. Taking advantage of its large aperture and infrared
polarimeters DKIST will be capable to routinely measure the currently
illusive coronal magnetic fields. The state-of-the-art adaptive optics
system provides diffraction limited imaging and the ability to resolve
features approximately 20 km on the Sun. Achieving this resolution
is critical for the ability to observe magnetic structures at their
intrinsic, fundamental scales. Five instruments will be available at
the start of operations, four of which will provide highly sensitive
measurements of solar magnetic fields throughout the solar atmosphere
- from the photosphere to the corona. The data from these instruments
will be distributed to the world wide community via the NSO/DKIST data
center located in Boulder. We present examples of science objectives
and provide an overview of the facility and project status, including
the ongoing efforts of the community to develop the critical science
plan for the first 2-3 years of operations.
---------------------------------------------------------
Title: Using a New Infrared Si X Coronal Emission Line for
Discriminating between Magnetohydrodynamic Models of the Solar Corona
During the 2006 Solar Eclipse
Authors: Dima, Gabriel I.; Kuhn, Jeffrey R.; Mickey, Don; Downs, Cooper
2018ApJ...852...23D Altcode:
During the 2006 March 29 total solar eclipse, coronal
spectropolarimetric measurements were obtained over a 6 × 6 R
<SUB>⊙</SUB> field of view with a 1-2 μm spectral range. The data
yielded linearly polarized measurements of the Fe XIII 1.075 μm, He
I 1.083 μm, and for the first time, of the Si X 1.430 μm emission
lines. To interpret the measurements, we used forward-integrated
synthetic emission from two magnetohydrodynamic models for the same
Carrington rotation with different heating functions and magnetic
boundary conditions. Observations of the Fe XIII 1.075/Si X 1.430 line
ratio allowed us to discriminate between two models of the corona,
with the observations strongly favoring the warmer model. The observed
polarized amplitudes for the Si X 1.430 μm line are around 7%,
which is three times higher than the predicted values from available
atomic models for the line. This discrepancy indicates a need for
a closer look at some of the model assumptions for the collisional
coefficients, as well as new polarized observations of the line to rule
out any unknown systematic effect in the present data. All but two
near-limb fibers show correlated bright He I 1.083 μm and H I 1.282
μm emission, which likely indicates cool prominence emission that is
non-localized by the strongly defocused optics. One of the distant
fibers located at 1.5 R <SUB>⊙</SUB> detected a weak He I 1.083
μm intensity signal consistent with previous eclipse measurements
around 3 × 10<SUP>-7</SUP> {B}<SUB>⊙ </SUB>. However, given the
limitations of these observations, it is not possible to completely
remove contamination that is due to emission from prominence material
that is not obscured by the lunar limb.
---------------------------------------------------------
Title: Constraining Line-of-sight Confusion in the Corona Using
Linearly Polarized Observations of the Infrared FeXIII 1075nm and
SiX 1430nm Emission Lines
Authors: Dima, G. I.; Kuhn, J. R.; Berdyugina, S.
2017AGUFMSH54A..03D Altcode:
Measurements of the coronal magnetic field are difficult because
of the intrinsically faint emission of coronal plasma and the large
spurious background due to the bright solar disk. This work addresses
the problem of resolving the confusion of the line-of-sight (LOS)
integration through the optically-thin corona being observed. Work on
developing new measuring techniques based on single-point inversions
using the Hanle effect has already been described (Dima et al. 2016). It
is important to develop a technique to assess when the LOS confusion
makes comparing models and observations problematic. Using forward
integration of synthetic emission through magnetohydrodynamic (MHD)
models together with simultaneous linearly polarized observations of
the FeXIII 1075nm and SiX 1430nm emission lines allows us to assess
LOS confusion. Since the lines are both in the Hanle saturated regime
their polarization angles are expected to be aligned as long as the
gas is sampling the same magnetic field. If significant contributions
to the emission is taking place from different regions along the LOS
due to the additive nature of the polarized brightness the measured
linear polarization between the two lines will be offset. The size
of the resolution element is important for this determination since
observing larger coronal regions will confuse the variation along the
LOS with that in the plane-of-sky. We also present comparisons between
synthetic linearly polarized emission through a global MHD model and
observations of the same regions obtained using the 0.5m Scatter-free
Observatory for Limb Active Regions and Coronae (SOLARC) telescope
located on Haleakala, Maui. This work is being done in preparation
for the type of observations that will become possible when the next
generation 4m DKIST telescope comes online in 2020.
---------------------------------------------------------
Title: Space Weathering of Super-Earths: Model Simulations of
Exospheric Sodium Escape from 61 Virgo b
Authors: Yoneda, M.; Berdyugina, S.; Kuhn, J.
2017AJ....154..139Y Altcode:
Rocky exoplanets are expected to be eroded by space weather in a
similar way as in the solar system. In particular, Mercury is one of the
dramatically eroded planets whose material continuously escapes into its
exosphere and further into space. This escape is well traced by sodium
atoms scattering sunlight. Due to solar wind impact, micrometeorite
impacts, photo-stimulated desorption and thermal desorption, sodium
atoms are released from surface regolith. Some of these released sodium
atoms are escaping from Mercury’s gravitational-sphere. They are
dragged anti-Sun-ward and form a tail structure. We expect similar
phenomena on exoplanets. The hot super-Earth 61 Vir b orbiting a
G3V star at only 0.05 au may show a similar structure. Because of
its small separation from the star, the sodium release mechanisms
may be working more efficiently on hot super-Earths than on Mercury,
although the strong gravitational force of Earth-sized or even more
massive planets may be keeping sodium atoms from escaping from the
planet. Here, we performed model simulations for Mercury (to verify
our model) and 61 Vir b as a representative super-Earth. We have found
that sodium atoms can escape from this exoplanet due to stellar wind
sputtering and micrometeorite impacts, to form a sodium tail. However,
in contrast to Mercury, the tail on this hot super-Earth is strongly
aligned with the anti-starward direction because of higher light
pressure. Our model suggests that 61 Vir b seems to have an exo-base
atmosphere like that of Mercury.
---------------------------------------------------------
Title: Partially Filled Aperture Interferometric Telescopes: Achieving
Large Aperture and Coronagraphic Performance
Authors: Moretto, G.; Kuhn, J.; Langlois, M.; Berdugyna, S.; Tallon, M.
2017EPSC...11..893M Altcode:
Telescopes larger than currently planned 30-m class instruments must
break the mass-aperture scaling relationship of the Keck-generation
of multi-segmented telescopes. Partially filled aperture, but highly
redundant baseline interferometric instruments may achieve both large
aperture and high dynamic range. The PLANETS FOUNDATION group has
explored hybrid telescope-interferometer concepts for narrow-field
optical systems that exhibit coronagraphic performance over narrow
fields-of-view. This paper describes how the Colossus and Exo-Life
Finder telescope designs achieve 10x lower moving masses than current
Extremely Large Telescopes.
---------------------------------------------------------
Title: First Detection of a Strong Magnetic Field on a Bursty Brown
Dwarf: Puzzle Solved
Authors: Berdyugina, S. V.; Harrington, D. M.; Kuzmychov, O.; Kuhn,
J. R.; Hallinan, G.; Kowalski, A. F.; Hawley, S. L.
2017ApJ...847...61B Altcode: 2017arXiv170902861B
We report the first direct detection of a strong, 5 kG magnetic field on
the surface of an active brown dwarf. LSR J1835+3259 is an M8.5 dwarf
exhibiting transient radio and optical emission bursts modulated by
fast rotation. We have detected the surface magnetic field as circularly
polarized signatures in the 819 nm sodium lines when an active emission
region faced the Earth. Modeling Stokes profiles of these lines reveals
the effective temperature of 2800 K and log gravity acceleration of
4.5. These parameters place LSR J1835+3259 on evolutionary tracks as
a young brown dwarf with the mass of 55+/- 4{M}<SUB>{{J</SUB>}} and
age of 22 ± 4 Myr. Its magnetic field is at least 5.1 kG and covers
at least 11% of the visible hemisphere. The active region topology
recovered using line profile inversions comprises hot plasma loops with
a vertical stratification of optical and radio emission sources. These
loops rotate with the dwarf in and out of view causing periodic emission
bursts. The magnetic field is detected at the base of the loops. This
is the first time that we can quantitatively associate brown dwarf
non-thermal bursts with a strong, 5 kG surface magnetic field and
solve the puzzle of their driving mechanism. This is also the coolest
known dwarf with such a strong surface magnetic field. The young age
of LSR J1835+3259 implies that it may still maintain a disk, which may
facilitate bursts via magnetospheric accretion, like in higher-mass
T Tau-type stars. Our results pave a path toward magnetic studies of
brown dwarfs and hot Jupiters.
---------------------------------------------------------
Title: Critical Infrared Science with the Daniel K. Inouye Solar
Telescope
Authors: Schad, Thomas A.; Fehlmann, Andre; Jaeggli, Sarah A.; Kuhn,
Jeffrey Richard; Lin, Haosheng; Penn, Matthew J.; Rimmele, Thomas R.;
Woeger, Friedrich
2017SPD....4811703S Altcode:
Critical science planning for early operations of the Daniel K. Inouye
Solar Telescope is underway. With its large aperture, all-reflective
telescope design, and advanced instrumentation, DKIST provides
unprecedented access to the important infrared (IR) solar spectrum
between 1 and 5 microns. Breakthrough IR capabilities in coronal
polarimetry will sense the coronal magnetic field routinely for the
first time. The increased Zeeman resolution near the photospheric
opacity minimum will provide our deepest and most sensitive measurement
of quiet sun and active region magnetic fields to date. High-sensitivity
He I triplet polarimetry will dynamically probe the chromospheric
magnetic field in fibrils, spicules, and filaments, while observations
of molecular CO transitions will characterize the coolest regions
of the solar atmosphere. When combined with the longer timescales
of good atmospheric seeing compared with the visible, DKIST infrared
diagnostics are expected to be mainstays of solar physics in the DKIST
era. This paper will summarize the critical science areas addressed
by DKIST infrared instrumentation and invite the community to further
contribute to critical infrared science planning.
---------------------------------------------------------
Title: The Cryogenic Near Infrared Spectropolarimeter for the Daniel
K. Inouye Solar Telescope
Authors: Fehlmann, Andre; Giebink, Cindy; Kuhn, Jeffrey Richard;
Mickey, D. L.; Scholl, Isabelle
2017SPD....4811702F Altcode:
The Cryogenic Near Infrared Spectropolarimeter is one of the first light
instruments for the Daniel K. Inouye Solar Telescope. This dual-beam
instrument, which is currently characterized at the University
of Hawaii’s Institute for Astronomy, is designed to sensitively
measure the solar spectrum at wavelengths from 1 to 5 μm. The high
dynamic range of the spectrograph and its context imager will provide
sensitive data of the solar disk in the CO bands; unique observations
of the low corona and unprecedented measurements of the coronal magnetic
field. Observations near the limb and in the corona will greatly benefit
from DKIST’s limb occulting system. The initial suite of filters
includes selecting filters for the spectrograph at He I / Fe XIII 1080
nm, Si X 1430 nm, Si IX 3934 nm and CO 4651 nm as well as narrow band
filters for the context imager at Fe XIII 1074.7 nm, He I 1083.0, Si X
1430.0 nm and J band 1250 nm. In this paper we will present an update on
the ongoing instrument characterization and CryoNIRSP’s capabilities.
---------------------------------------------------------
Title: Daytime sky polarization calibration limitations
Authors: Harrington, David M.; Kuhn, Jeffrey R.; Ariste, Arturo López
2017JATIS...3a8001H Altcode: 2016arXiv161200538H
The daytime sky has recently been demonstrated as a useful calibration
tool for deriving polarization cross-talk properties of large
astronomical telescopes. The Daniel K. Inouye Solar Telescope and
other large telescopes under construction can benefit from precise
polarimetric calibration of large mirrors. Several atmospheric phenomena
and instrumental errors potentially limit the technique's accuracy. At
the 3.67-m AEOS telescope on Haleakala, we performed a large observing
campaign with the HiVIS spectropolarimeter to identify limitations and
develop algorithms for extracting consistent calibrations. Effective
sampling of the telescope optical configurations and filtering of data
for several derived parameters provide robustness to the derived Mueller
matrix calibrations. Second-order scattering models of the sky show
that this method is relatively insensitive to multiple-scattering in
the sky, provided calibration observations are done in regions of high
polarization degree. The technique is also insensitive to assumptions
about telescope-induced polarization, provided the mirror coatings are
highly reflective. Zemax-derived polarization models show agreement
between the functional dependence of polarization predictions and the
corresponding on-sky calibrations.
---------------------------------------------------------
Title: Daniel K. Inouye Solar Telescope: High-resolution observing
of the dynamic Sun
Authors: Tritschler, A.; Rimmele, T. R.; Berukoff, S.; Casini, R.;
Kuhn, J. R.; Lin, H.; Rast, M. P.; McMullin, J. P.; Schmidt, W.;
Wöger, F.; DKIST Team
2016AN....337.1064T Altcode:
The 4-m aperture Daniel K. Inouye Solar Telescope (DKIST) formerly
known as the Advanced Technology Solar Telescope (ATST) is currently
under construction on Haleakalā (Maui, Hawai'i) projected to
start operations in 2019. At the time of completion, DKIST will be
the largest ground-based solar telescope providing unprecedented
resolution and photon collecting power. The DKIST will be equipped
with a set of first-light facility-class instruments offering unique
imaging, spectroscopic and spectropolarimetric observing opportunities
covering the visible to infrared wavelength range. This first-light
instrumentation suite will include: a Visible Broadband Imager (VBI) for
high-spatial and -temporal resolution imaging of the solar atmosphere; a
Visible Spectro-Polarimeter (ViSP) for sensitive and accurate multi-line
spectropolarimetry; a Fabry-Pérot based Visible Tunable Filter
(VTF) for high-spatial resolution spectropolarimetry; a fiber-fed
Diffraction-Limited Near Infra-Red Spectro-Polarimeter (DL-NIRSP)
for two-dimensional high-spatial resolution spectropolarimetry
(simultaneous spatial and spectral information); and a Cryogenic Near
Infra-Red Spectro-Polarimeter (Cryo-NIRSP) for coronal magnetic field
measurements and on-disk observations of, e.g., the CO lines at 4.7
μm. We will provide an overview of the DKIST's unique capabilities
with strong focus on the first-light instrumentation suite, highlight
some of the additional properties supporting observations of transient
and dynamic solar phenomena, and touch on some operational strategies
and the DKIST critical science plan.
---------------------------------------------------------
Title: Cryogenic near infrared spectropolarimeter for the Daniel
K. Inouye Solar Telescope
Authors: Fehlmann, Andre; Giebink, Cynthia; Kuhn, Jeffrey R.;
Messersmith, Ernesto J.; Mickey, Donald L.; Scholl, Isabelle F.;
James, Don; Hnat, Kirby; Schickling, Greg; Schickling, Richard
2016SPIE.9908E..4DF Altcode:
The Cryogenic Near Infrared Spectropolarimeter for the Daniel K Inouye
Solar Telescope is designed to measure polarized light from 0.5 to 5
μm. It uses an almost all reflective design for high throughput and
an R2 echelle grating to achieve the required resolution of up to R =
100,000. The optics cooled to cryogenic temperatures reduce the thermal
background allowing for IR observations of the faint solar corona. Both
the spectrograph and its context imager use H2RG detector arrays with
a newly designed controller to allow synchronized exposures at frame
rates up to 10 Hz. All hardware has been built and tested and the
key components met their design goals. 1) The cryogenic system uses
mechanical closed cycle coolers which introduce vibrations. Our design
uses a two stage approach with a floating mounting disk and flexible
cold links to reduce these. The vibration amplitudes on all critical
stages were measured and are smaller than 1μm. 2) The grating stage
of the spectrograph uses a double stack of harmonic drives and an
optical encoder to provide sub-arcsecond resolution and a measured
repeatability of better than 0.5 arcsec.
---------------------------------------------------------
Title: Daytime sky polarization calibration limitations
Authors: Harrington, David M.; Kuhn, Jeffrey R.; López Ariste, Arturo
2016SPIE.9912E..6SH Altcode:
The daytime sky has been recently demonstrated as a useful
calibration tool for deriving polarization cross-talk properties of
large astronomical telescopes. The Daniel K Inouye Solar Telescope
(DKIST) and other large telescopes under construction can benefit from
precise polarimetric calibration of large off-axis mirrors. Several
atmospheric phenomena and instrumental errors potentially limit the
techniques accuracy. At the 3.67m AEOS telescope on Haleakala, we have
performed a large observing campaign with the HiVIS spectropolarimeter
to identify limitations and develop algorithms for extracting consistent
calibrations. Effective sampling of the telescope optical configurations
and filtering of data for several derived parameters provide robustness
to the derivedMueller matrix calibrations. Second-order scattering
models of the sky show that this method is relatively insensitive to
assumptions about telescope induced polarization provided the mirror
coatings are highly reflective. Zemax-derived polarization models show
agreement between predictions and on-sky calibrations.
---------------------------------------------------------
Title: IR heterodyne spectrometer MILAHI for continuous monitoring
observatory of Martian and Venusian atmospheres at Mt. Haleakalā,
Hawaii
Authors: Nakagawa, Hiromu; Aoki, Shohei; Sagawa, Hideo; Kasaba,
Yasumasa; Murata, Isao; Sonnabend, Guido; Sornig, Manuela; Okano,
Shoichi; Kuhn, Jeffrey R.; Ritter, Joseph M.; Kagitani, Masato;
Sakanoi, Takeshi; Taguchi, Makoto; Takami, Kosuke
2016P&SS..126...34N Altcode:
A new Mid-Infrared Laser Heterodyne Instrument (MILAHI) with
>10<SUP>6</SUP> resolving power at 7-12 μm was developed for
continuous monitoring of planetary atmospheres by using dedicated
ground-based telescopes for planetary science at Mt. Haleakalā,
Hawaii. Room-temperature-type quantum cascade lasers (QCLs) that
cover wavelength ranges of 7.69-7.73, 9.54-9.59, and 10.28-10.33 μm
have been newly installed as local oscillators to allow observation
of CO<SUB>2</SUB>, CH<SUB>4</SUB>, H<SUB>2</SUB>O<SUB>2</SUB>,
H<SUB>2</SUB>O, and HDO. Modeling and predictions by radiative transfer
code gave the following scientific capabilities and measurement
sensitivities of the MILAHI. (1) Temperature profiles are achieved
at altitudes of 65-90 km on Venus, and the ground surface to 30 km
on Mars. (2) New wind profiles are provided at altitudes of 75-90
km on Venus, and 5-25 km on Mars. (3) Direct measurements of the
mesospheric wind and temperature are obtained from the Doppler-shifted
emission line at altitudes of 110 km on Venus and 75 km on Mars. (4)
Detections of trace gases and isotopic ratios are performed without any
ambiguity of the reproducing the terrestrial atmospheric absorptions
in the observed wavelength range. A HDO measurement of twice the Vienna
Standard Mean Ocean Water (VSMOW) can be obtained by 15-min integration,
while H<SUB>2</SUB>O of 75 ppm is provided by 3.62-h integration. The
detectability of the 100 ppb-CH<SUB>4</SUB> on Mars corresponds to an
integration time of 32 h.
---------------------------------------------------------
Title: The SCExAO high contrast imager: transitioning from
commissioning to science
Authors: Jovanovic, N.; Guyon, O.; Lozi, J.; Currie, T.; Hagelberg,
J.; Norris, B.; Singh, G.; Pathak, P.; Doughty, D.; Goebel, S.; Males,
J.; Kuhn, J.; Serabyn, E.; Tuthill, P.; Schworer, G.; Martinache, F.;
Kudo, T.; Kawahara, H.; Kotani, T.; Ireland, M.; Feger, T.; Rains,
A.; Bento, J.; Schwab, C.; Coutts, D.; Cvetojevic, N.; Gross, S.;
Arriola, A.; Lagadec, T.; Kasdin, J.; Groff, T.; Mazin, B.; Minowa,
Y.; Takato, N.; Tamura, M.; Takami, H.; Hayashi, M.
2016SPIE.9909E..0WJ Altcode:
SCExAO is the premier high-contrast imaging platform for the Subaru
Telescope. It offers high Strehl ratios at near-IR wavelengths (y-K
band) with stable pointing and coronagraphs with extremely small inner
working angles, optimized for imaging faint companions very close
to the host. In the visible, it has several interferometric imagers
which offer polarimetric and spectroscopic capabilities. A recent
addition is the RHEA spectrograph enabling spatially resolved high
resolution spectroscopy of the surfaces of giant stars, for example. New
capabilities on the horizon include post-coronagraphic spectroscopy,
spectral differential imaging, nulling interferometry as well as an
integral field spectrograph and an MKID array. Here we present the
new modules of SCExAO, give an overview of the current commissioning
status of each of the modules and present preliminary results.
---------------------------------------------------------
Title: Construction Status and Early Science with the Daniel K. Inouye
Solar Telescope
Authors: McMullin, Joseph P.; Rimmele, Thomas R.; Warner, Mark;
Martinez Pillet, Valentin; Craig, Simon; Woeger, Friedrich; Tritschler,
Alexandra; Berukoff, Steven J.; Casini, Roberto; Goode, Philip R.;
Knoelker, Michael; Kuhn, Jeffrey Richard; Lin, Haosheng; Mathioudakis,
Mihalis; Reardon, Kevin P.; Rosner, Robert; Schmidt, Wolfgang
2016SPD....4720101M Altcode:
The 4-m Daniel K. Inouye Solar Telescope (DKIST) is in its seventh
year of overall development and its fourth year of site construction
on the summit of Haleakala, Maui. The Site Facilities (Utility
Building and Support & Operations Building) are in place with
ongoing construction of the Telescope Mount Assembly within. Off-site
the fabrication of the component systems is completing with early
integration testing and verification starting.Once complete this
facility will provide the highest sensitivity and resolution for study
of solar magnetism and the drivers of key processes impacting Earth
(solar wind, flares, coronal mass ejections, and variability in solar
output). The DKIST will be equipped initially with a battery of first
light instruments which cover a spectral range from the UV (380 nm)
to the near IR (5000 nm), and capable of providing both imaging and
spectro-polarimetric measurements throughout the solar atmosphere
(photosphere, chromosphere, and corona); these instruments are being
developed by the National Solar Observatory (Visible Broadband Imager),
High Altitude Observatory (Visible Spectro-Polarimeter), Kiepenheuer
Institute (Visible Tunable Filter) and the University of Hawaii
(Cryogenic Near-Infrared Spectro-Polarimeter and the Diffraction-Limited
Near-Infrared Spectro-Polarimeter). Further, a United Kingdom consortium
led by Queen's University Belfast is driving the development of high
speed cameras essential for capturing the highly dynamic processes
measured by these instruments. Finally, a state-of-the-art adaptive
optics system will support diffraction limited imaging capable of
resolving features approximately 20 km in scale on the Sun.We present
the overall status of the construction phase along with the current
challenges as well as a review of the planned science testing and the
transition into early science operations.
---------------------------------------------------------
Title: Infrared Dual-line Hanle diagnostic of the Coronal Vector
Magnetic Field
Authors: Dima, Gabriel; Kuhn, Jeffrey; Berdyugina, Svetlana
2016FrASS...3...13D Altcode:
Measuring the coronal vector magnetic field is still a major challenge
in solar physics. This is due to the intrinsic weakness of the field
(e.g. ~4G at a height of 0.1Rsun above an active region) and the
large thermal broadening of coronal emission lines. We propose using
concurrent linear polarization measurements of near-infrared forbidden
and permitted lines together with Hanle effect models to calculate
the coronal vector magnetic field. In the unsaturated Hanle regime
both the direction and strength of the magnetic field affect the
linear polarization, while in the saturated regime the polarization
is insensitive to the strength of the field. The relatively long
radiative lifetimes of coronal forbidden atomic transitions implies
that the emission lines are formed in the saturated Hanle regime
and the linear polarization is insensitive to the strength of the
field. By combining measurements of both forbidden and permitted lines,
the direction and strength of the field can be obtained. For example,
the SiX 1.4301 um line shows strong linear polarization and has been
observed in emission over a large field-of-view (out to elongations
of 0.5 Rsun. Here we describe an algorithm that combines linear
polarization measurements of the SiX 1.4301 um forbidden line with
linear polarization observations of the HeI 1.0830 um permitted coronal
line to obtain the vector magnetic field. To illustrate the concept we
assume the emitting gas for both atomic transitions is located in the
plane of the sky. The further development of this method and associated
tools will be a critical step towards interpreting the high spectral,
spatial and temporal infrared spectro-polarimetric measurements that
will be possible when the Daniel K. Inouye Solar Telescope (DKIST)
is completed in 2019.
---------------------------------------------------------
Title: Haleakalā Sky Polarization: Full-Sky Observations and Modeling
Authors: Swindle, R.; Kuhn, J. R.
2015PASP..127.1061S Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Discovery of a Low-mass Companion Around HR 3549
Authors: Mawet, D.; David, T.; Bottom, M.; Hinkley, S.; Stapelfeldt,
K.; Padgett, D.; Mennesson, B.; Serabyn, E.; Morales, F.; Kuhn, J.
2015ApJ...811..103M Altcode: 2015arXiv150905689M
We report the discovery of a low-mass companion to HR 3549, an A0V
star surrounded by a debris disk with a warm excess detected by WISE
at 22 μm (10σ significance). We imaged HR 3549 B in the L band with
NAOS-CONICA, the adaptive optics infrared camera of the Very Large
Telescope, in January 2013 and confirmed its common proper motion in
2015 January. The companion is at a projected separation of ≃80 AU
and position angle of ≃157°, so it is orbiting well beyond the warm
disk inner edge of r > 10 AU. Our age estimate for this system
corresponds to a companion mass in the range 15-80 M<SUB>J</SUB>,
spanning the brown dwarf regime, and so HR 3549 B is another recent
addition to the growing list of brown dwarf desert objects with
extreme mass ratios. The simultaneous presence of a warm disk and a
brown dwarf around HR 3549 provides interesting empirical constraints
on models of the formation of substellar companions.
---------------------------------------------------------
Title: The Subaru Coronagraphic Extreme Adaptive Optics System:
Enabling High-Contrast Imaging on Solar-System Scales
Authors: Jovanovic, N.; Martinache, F.; Guyon, O.; Clergeon, C.;
Singh, G.; Kudo, T.; Garrel, V.; Newman, K.; Doughty, D.; Lozi, J.;
Males, J.; Minowa, Y.; Hayano, Y.; Takato, N.; Morino, J.; Kuhn,
J.; Serabyn, E.; Norris, B.; Tuthill, P.; Schworer, G.; Stewart, P.;
Close, L.; Huby, E.; Perrin, G.; Lacour, S.; Gauchet, L.; Vievard,
S.; Murakami, N.; Oshiyama, F.; Baba, N.; Matsuo, T.; Nishikawa, J.;
Tamura, M.; Lai, O.; Marchis, F.; Duchene, G.; Kotani, T.; Woillez, J.
2015PASP..127..890J Altcode: 2015arXiv150700017J
The Subaru Coronagraphic Extreme Adaptive Optics (SCExAO) instrument
is a multipurpose high-contrast imaging platform designed for the
discovery and detailed characterization of exoplanetary systems and
serves as a testbed for high-contrast imaging technologies for ELTs. It
is a multi-band instrument which makes use of light from 600 to 2500nm
allowing for coronagraphic direct exoplanet imaging of the inner 3
lambda/D from the stellar host. Wavefront sensing and control are key
to the operation of SCExAO. A partial correction of low-order modes is
provided by Subaru's facility adaptive optics system with the final
correction, including high-order modes, implemented downstream by a
combination of a visible pyramid wavefront sensor and a 2000-element
deformable mirror. The well corrected NIR (y-K bands) wavefronts can
then be injected into any of the available coronagraphs, including but
not limited to the phase induced amplitude apodization and the vector
vortex coronagraphs, both of which offer an inner working angle as low
as 1 lambda/D. Non-common path, low-order aberrations are sensed with
a coronagraphic low-order wavefront sensor in the infrared (IR). Low
noise, high frame rate, NIR detectors allow for active speckle nulling
and coherent differential imaging, while the HAWAII 2RG detector
in the HiCIAO imager and/or the CHARIS integral field spectrograph
(from mid 2016) can take deeper exposures and/or perform angular,
spectral and polarimetric differential imaging. Science in the visible
is provided by two interferometric modules: VAMPIRES and FIRST, which
enable sub-diffraction limited imaging in the visible region with
polarimetric and spectroscopic capabilities respectively. We describe
the instrument in detail and present preliminary results both on-sky
and in the laboratory.
---------------------------------------------------------
Title: Correcting Systematic Polarization Effects in Keck LRISp
Spectropolarimetry to < 0.05%
Authors: Harrington, David M.; Berdyugina, Svetlana V.; Kuzmychov,
Oleksii; Kuhn, Jeffrey R.
2015PASP..127..757H Altcode: 2015arXiv150503916H
Spectropolarimetric measurements at moderate spectral resolutions
are effective tracers of stellar magnetic fields and circumstellar
environments when signal to noise ratios (SNRs) above 2000 can be
achieved. The LRISp spectropolarimeter is capable of achieving these
SNRs on faint targets with the 10m aperture of the Keck telescope,
provided several instrumental artifacts can be suppressed. We describe
here several methods to overcome instrumental error sources that
are required to achieve these high SNRs on LRISp. We explore high SNR
techniques such as defocusing and slit-stepping during integration with
high spectral and spatial oversampling. We find that the instrument
flexure and interference fringes introduced by the achromatic retarders
create artificial signals at 0.5\% levels in the red channel which mimic
real stellar signals and limit the sensitivity and calibration stability
of LRISp. Careful spectral extraction and data filtering algorithms
can remove these error sources. For faint targets and long exposures,
cosmic ray hits are frequent and present a major limitation to the
upgraded deep depletion red-channel CCD. These must be corrected to
the same high SNR levels, requiring careful spectral extraction using
iterative filtering algorithms. We demonstrate here characterization
of these sources of instrumental polarization artifacts and present
several methods used to successfully overcome these limitations. We
have measured the linear to circular cross-talk and find it to be
roughly 5\%, consistent with the known instrument limitations. We show
spectropolarimetric signals on brown dwarfs are clearly detectable
at 0.2\% amplitudes with sensitivities better than 0.05\% at full
spectral sampling in atomic and molecular bands. Future LRISp users
can perform high sensitivity observations with high quality calibration
when following the described algorithms.
---------------------------------------------------------
Title: Calibrating and stabilizing spectropolarimeters with charge
shuffling and daytime sky measurements
Authors: Harrington, D.; Kuhn, J. R.; Nevin, R.
2015A&A...578A.126H Altcode: 2015arXiv150306744H
Well-calibrated spectropolarimetry studies at resolutions of R
> 10 000 with signal-to-noise ratios (S/Ns) better than 0.01%
across individual line profiles, are becoming common with larger
aperture telescopes. Spectropolarimetric studies require high S/N
observations and are often limited by instrument systematic errors. As
an example, fiber-fed spectropolarimeters combined with advanced
line-combination algorithms can reach statistical error limits of
0.001% in measurements of spectral line profiles referenced to the
continuum. Calibration of such observations is often required both for
cross-talk and for continuum polarization. This is not straightforward
since telescope cross-talk errors are rarely less than ~1%. In solar
instruments like the Daniel K. Inouye Solar Telescope (DKIST), much
more stringent calibration is required and the telescope optical
design contains substantial intrinsic polarization artifacts. This
paper describes some generally useful techniques we have applied
to the HiVIS spectropolarimeter at the 3.7 m AEOS Telescope on
Haleakala. HiVIS now yields accurate polarized spectral line profiles
that are shot-noise limited to 0.01% S/N levels at our full spectral
resolution of 10 000 at spectral sampling of ~100 000. We show line
profiles with absolute spectropolarimetric calibration for cross-talk
and continuum polarization in a system with polarization cross-talk
levels of essentially 100%. In these data the continuum polarization
can be recovered to one percent accuracy because of synchronized
charge-shuffling model now working with our CCD detector. These
techniques can be applied to other spectropolarimeters on other
telescopes for both night and daytime applications such as DKIST, TMT,
and ELT which have folded non-axially symmetric foci.
---------------------------------------------------------
Title: Measuring the Solar Radius from Space during the 2012 Venus
Transit
Authors: Emilio, M.; Couvidat, S.; Bush, R. I.; Kuhn, J. R.; Scholl,
I. F.
2015ApJ...798...48E Altcode:
We report in this work the determination of the solar radius from
observations by the Helioseismic and Magnetic Imager (HMI) and the
Atmospheric Imaging Assembly (AIA) instruments on board the Solar
Dynamics Observatory during the 2012 June Venus transit of the Sun. Two
different methods were utilized to determine the solar radius using
images of Sun taken by the HMI instrument. The first technique fit the
measured trajectory of Venus in front of the Sun for seven wavelengths
across the Fe I absorption line at 6173 Å. The solar radius determined
from this method varies with the measurement wavelength, reflecting the
variation in the height of line formation. The second method measured
the area of the Sun obscured by Venus to determine the transit duration
from which the solar radius was derived. This analysis focused on
measurements taken in the continuum wing of the line, and applied a
correction for the instrumental point spread function (PSF) of the
HMI images. Measurements taken in the continuum wing of the 6173 Å
line, resulted in a derived solar radius at 1 AU of 959.”57 ± 0.”02
(695, 946 ± 15 km). The AIA instrument observed the Venus transit at
ultraviolet wavelengths. Using the solar disk obscuration technique,
similar to that applied to the HMI images, analysis of the AIA data
resulted in values of R <SUB>⊙</SUB> = 963.”04 ± 0.”03 at 1600
Å and R <SUB>⊙</SUB> = 961.”76 ± 0.”03 at 1700 Å.
---------------------------------------------------------
Title: DKIST: Observing the Sun at High Resolution
Authors: Tritschler, A.; Rimmele, T. R.; Berukoff, S.; Casini, R.;
Craig, S. C.; Elmore, D. F.; Hubbard, R. P.; Kuhn, J. R.; Lin, H.;
McMullin, J. P.; Reardon, K. P.; Schmidt, W.; Warner, M.; Woger, F.
2015csss...18..933T Altcode:
The 4-m aperture Daniel K. Inouye Solar Telescope (DKIST) formerly
known as the Advanced Technology Solar Telescope (ATST) and currently
under construction on Haleakalā (Maui, Hawai'i) will be the largest
solar ground-based telescope and leading resource for studying the
dynamic Sun and its phenomena at high spatial, spectral and temporal
resolution. Accurate and sensitive polarimetric observations at
high-spatial resolution throughout the solar atmosphere including the
corona is a high priority and a major science driver. As such the DKIST
will offer a combination of state-of-the-art instruments with imaging
and/or spectropolarimetric capabilities covering a broad wavelength
range. This first-light instrumentation suite will include: a Visible
Broadband Imager (VBI) for high-spatial and -temporal resolution
imaging of the solar atmosphere; a Visible Spectro-Polarimeter (ViSP)
for sensitive and accurate multi-line spectropolarimetry; a double
Fabry-Pérot based Visible Tunable Filter (VTF) for high-spatial
resolution spectropolarimetry; a fiber-fed 2D Diffraction-Limited Near
Infra-Red Spectro-Polarimeter (DL-NIRSP); and a Cryogenic Near Infra-Red
Spectro-Polarimeter (Cryo-NIRSP) for coronal magnetic field measurements
and on-disk observations of e.g. the CO lines at 4.7 microns. We
will provide a brief overview of the DKIST's unique capabilities to
perform spectroscopic and spectropolarimetric measurements of the solar
atmosphere using its first-light instrumentation suite, the status of
the construction project, and how facility and data access is provided
to the US and international community.
---------------------------------------------------------
Title: Microarsecond Solar Limb Astrometry from Space
Authors: Kuhn, J. R.; Cunnyngham, I.; Bush, R. I.; Emilio, M.; Scholl,
I. F.
2014AGUFMSH41C4157K Altcode:
The solar limb astrometry program for HMI has accumulated several
years of precise limb brightness and shape measurements. From above
the Earth's atmosphere, with the stable SDO/HMI instrument platform,
individual limb measurements are accurate to the 10's of milliarcsecond
level. The combined timeseries of solar limb shape is sensitive to
solar shape perturbations at the submicroarcsecond level. Oscillatory
phenomena (like solar g- and r-modes) may be detected at low frequencies
with effective velocity amplitudes of 10's of microns per second. We
describe here the low frequency shape and limb brightness oscillations
observed by HMI from 1 - 3000 microHz.
---------------------------------------------------------
Title: Combining Linear Polarization Measurements of both
Forbidden/Permitted Coronal Emission Lines for measuring the Vector
Magnetic Field in the Solar Corona
Authors: Dima, G. I.; Kuhn, J. R.; Mickey, D.
2014AGUFMSH23C..03D Altcode:
Measuring the coronal vector magnetic field is still a major challenge
in solar physics. This is due to the intrinsic weakness of the field (~4
G at a height of 0.1 Rsun above an active region) and the large thermal
broadening of coronal emission lines. Current methods deduce either
the direction of the magnetic field or the magnetic flux density. We
propose using concurrent linear polarization measurements in the near
IR of forbidden and permitted lines to calculate the coronal vector
magnetic field. The effect of the magnetic field on the polarization
properties of emitted light is encapsulated in the Hanle effect. In
the unsaturated Hanle regime both the direction and strength of the
magnetic field affect the linear polarization, while for saturated Hanle
the polarization is insensitive to the strength of the field. Coronal
forbidden lines are always in the saturated Hanle regime so the linear
polarization holds no information on the strength of the field. By
pairing measurements of both forbidden and permitted lines we would
be able to obtain both the direction and strength of the field. The
near-IR region of the spectrum offers the opportunity to study this
problem from the ground. The FeXIII 1.075 um and SiX 1.431 um forbidden
lines are strongly polarizable and are sufficiently bright over a
large field of view (out to 1.5 Rsun). Measurements of both these
lines can be paired up with the recently observed coronal HeI 1.083
um permitted line. The first data set used to test this technique was
taken during the March 29, 2006 total solar eclipse and consisted of
near-IR spectra covering the spectral region 0.9-1.8 um, with a field of
view of 3 x 3 Rsun. The data revealed unexpectedly strong SiX emission
compared to FeXIII. Using the HAO FORWARD suite of codes we produced
simulated emission maps from a global HMD model for the day of the
eclipse. Comparing the intensity variation of the measurements and the
model we predict that SiX emission is more extended for this day that
the model would suggest, further supporting the possible usefulness
of SiX polarimetry. The development of this method and associated
tools will be critical in interpreting the high spectral, spatial
and temporal IR measurements that will be possible when the Daniel
K. Inouye Solar Telescope (DKIST) is completed in a few years time.
---------------------------------------------------------
Title: A Mach-Zender Holographic Microscope for Quantifying Bacterial
Motility
Authors: Niraula, B.; Nadeau, J. L.; Serabyn, E.; Wallace, J. K.;
Liewer, K.; Kuhn, J.; Graff, E.; Lindensmith, C.
2014AGUFM.P53A4004N Altcode:
New microscopic techniques have revolutionized cell biology over the
past two decades. However, there are still biological processes whose
details elude us, especially those involving motility: e.g. feeding
behavior of microorganisms in the ocean, or migration of cancer cells to
form metastases. Imaging prokaryotes, which range in size from several
hundred nm to a few microns, is especially challenging. An emerging
technique to address these issues is Digital Holographic Microscopy
(DHM). DHM is an imaging technique that uses the interference of
light to record and reproduce three-dimensional magnified images
of objects. This approach has several advantages over ordinary
brightfield microscopy for fieldwork: a larger depth of field,
hands-off operation, robustness regarding environmental conditions,
and large sampling volumes with quantitative 3D records of motility
behavior. Despite these promising features, real-time DHM was thought
to be impractical for technological and computational reasons until
recently, and there has so far been very limited application of DHM
to biology. Most existing instruments are limited in performance by
their particular (e.g. in-line, lens-less, phase-shifting) approach
to holography. These limitations can be mitigated with an off-axis
dual-path configuration. Here we describe the design and implementation
of a design for a Mach-Zehnder-type holographic microscope with
diffraction-limited lateral resolution, with intended applications in
environmental microbiology. We have achieved sub-micron resolution
and three-dimensional tracking of prokaryotic and eukaryotic test
strains designed to represent different modes and speeds of microbial
motility. Prokaryotes are Escherichia coli, Vibrio alginolyticus,
and Bacillus subtilis. Each shows a characteristic motility pattern,
as we illustrate in holographic videos in sample chambers 0.6 mm in
depth. The ability to establish gradients of attractants with bacterial
taxis towards the attractant is also established. The eukaryotic
strains are Euglena gracilis, which demonstrates both phototaxis
and geotaxis, and Paramecium micromultinucleatum. The challenges of
optimizing resolution vs. field of view, and of handling the large
volumes of data generated during holographic imaging, are discussed.
---------------------------------------------------------
Title: Bacterial Motility As a Biosignature: Tests at Icy Moon
Analogue Sites
Authors: Nadeau, J. L.; Lindensmith, C.; Deming, J. W.; Stocker, R.;
Graff, E.; Serabyn, E.; Wallace, J. K.; Liewer, K.; Kuhn, J.
2014AGUFM.P53A4005N Altcode:
Extraterrestrial life in our Solar System, if present, is almost certain
to be microbial. Methods and technologies for unambiguous detection
of living or extinct microorganisms are needed for life-detection
missions to the Jovian and Saturnian moons, where liquid water
is known to exist. Our research focuses specifically on microbial
meaningful motion as a biosignature—"waving crowds" at the micron
scale. Digital Holographic Microscopy (DHM) is an excellent tool for
unambiguous identification of bacterial and protozoal swimming, even
in the presence of turbidity, drift, and currents. The design of a
holographic instrument with bacteria scale resolution was described
in the previous talk. In this presentation, we will illustrate the
design challenges for construction of a field instrument for extreme
environments and space, and present plans for scientific investigations
at analogue sites for the coming season. The challenges of creating
a field instrument involve performance trade-offs, the ability to
operate at extreme temperatures, and handling large volumes of data. A
fully autonomous instrument without external cables or power is also
desirable, and this is something that previous holographic instruments
have not achieved. The primary issues for space exploration are
identification of a laser and drive electronics that are qualified
for the expected radiation environments of the moons around gas
giant planets. Tests in Earth analogue environments will establish
performance parameters as well as answer scientific questions that
traditional microscopic techniques cannot. Specifically, we will visit
a Greenland field site to determine whether or not microorganisms are
motile within the brine-filled interior network of sea ice, and if they
can be autonomously tracked using the instrument. Motility within the
liquid phase of a frozen matrix has been hypothesized to explain how
bacteria contribute to the biogeochemical signatures detected in ice,
but observational evidence of motility in natural samples at subzero
temperatures does not exist. Complementing tests for bacterial motility
in ice-brines, we will also test for motility in the subzero waters
directly beneath the ice, where motility has long been suspected but
also never observed.
---------------------------------------------------------
Title: The Daniel K. Inouye Solar Telescope: A Project Update.
Authors: Rimmele, T.; Berger, T.; McMullin, J.; Warner, M.; Casinsi,
R.; Kuhn, J.; Lin, H.; Woeger, F.; Schmidt, W.; Tritschler, A.;
Inouye, Daniel K.; Solar Telescope Team
2014amos.confE..43R Altcode:
The Advanced Technology Solar Telescope will be the largest solar
facility ever built. Designed and developed to meet the needs of
critical high resolution and high sensitivity spectral and polarimetric
observations of the sun, this facility will support key experiments
for the study of solar magnetism and its influence on the solar wind,
flares, coronal mass ejections and solar irradiance variability. The
4-meter diameter facility will operate over a broad wavelength range
(0.35 to 28 microns), using state-of-the-art adaptive optics systems to
provide diffraction limited imaging and the ability to resolve features
approximately 20 km on the Sun. Five first light instruments will be
available at the start of operations. Key subsystems have been designed
and fabrication is well underway, including the site construction,
which began in December 2012. We provide an update on the development
of the facilities both on site at the Haleakala Observatories in Maui
and the development of components around the world. We present the
overall construction and integration schedule leading to the start of
operations in mid-2019 and touch on operations aspects.
---------------------------------------------------------
Title: Construction status of the Daniel K. Inouye Solar Telescope
Authors: McMullin, Joseph P.; Rimmele, Thomas R.; Martínez Pillet,
Valentin; Berger, Thomas E.; Casini, Roberto; Craig, Simon C.; Elmore,
David F.; Goodrich, Bret D.; Hegwer, Steve L.; Hubbard, Robert P.;
Johansson, Erik M.; Kuhn, Jeffrey R.; Lin, Haosheng; McVeigh, William;
Schmidt, Wolfgang; Shimko, Steve; Tritschler, Alexandra; Warner,
Mark; Wöger, Friedrich
2014SPIE.9145E..25M Altcode:
The Daniel K. Inouye Solar Telescope (DKIST, renamed in December 2013
from the Advanced Technology Solar Telescope) will be the largest
solar facility built when it begins operations in 2019. Designed
and developed to meet the needs of critical high resolution and high
sensitivity spectral and polarimetric observations of the Sun, the
observatory will enable key research for the study of solar magnetism
and its influence on the solar wind, flares, coronal mass ejections
and solar irradiance variations. The 4-meter class facility will
operate over a broad wavelength range (0.38 to 28 microns, initially
0.38 to 5 microns), using a state-of-the-art adaptive optics system to
provide diffraction-limited imaging and the ability to resolve features
approximately 25 km on the Sun. Five first-light instruments will be
available at the start of operations: Visible Broadband Imager (VBI;
National Solar Observatory), Visible SpectroPolarimeter (ViSP; NCAR High
Altitude Observatory), Visible Tunable Filter (VTF; Kiepenheuer Institut
für Sonnenphysik), Diffraction Limited Near InfraRed SpectroPolarimeter
(DL-NIRSP; University of Hawai'i, Institute for Astronomy) and the
Cryogenic Near InfraRed SpectroPolarimeter (Cryo-NIRSP; University of
Hawai'i, Institute for Astronomy). As of mid-2014, the key subsystems
have been designed and fabrication is well underway, including the
site construction, which began in December 2012. We provide an update
on the development of the facilities both on site at the Haleakalā
Observatories on Maui and the development of components around the
world. We present the overall construction and integration schedule
leading to the handover to operations in mid 2019. In addition, we
outline the evolving challenges being met by the project, spanning the
full spectrum of issues covering technical, fiscal, and geographical,
that are specific to this project, though with clear counterparts to
other large astronomical construction projects.
---------------------------------------------------------
Title: Development and recent results from the Subaru coronagraphic
extreme adaptive optics system
Authors: Jovanovic, N.; Guyon, O.; Martinache, F.; Clergeon, C.;
Singh, G.; Kudo, T.; Newman, K.; Kuhn, J.; Serabyn, E.; Norris, B.;
Tuthill, P.; Stewart, P.; Huby, E.; Perrin, G.; Lacour, S.; Vievard,
S.; Murakami, N.; Fumika, O.; Minowa, Y.; Hayano, Y.; White, J.; Lai,
O.; Marchis, F.; Duchene, G.; Kotani, T.; Woillez, J.
2014SPIE.9147E..1QJ Altcode:
The Subaru Coronagraphic Extreme Adaptive Optics (SCExAO) instrument
is one of a handful of extreme adaptive optics systems set to come
online in 2014. The extreme adaptive optics correction is realized by
a combination of precise wavefront sensing via a non-modulated pyramid
wavefront sensor and a 2000 element deformable mirror. This system
has recently begun on-sky commissioning and was operated in closed
loop for several minutes at a time with a loop speed of 800 Hz, on
~150 modes. Further suppression of quasi-static speckles is possible
via a process called "speckle nulling" which can create a dark hole
in a portion of the frame allowing for an enhancement in contrast,
and has been successfully tested on-sky. In addition to the wavefront
correction there are a suite of coronagraphs on board to null out
the host star which include the phase induced amplitude apodization
(PIAA), the vector vortex, 8 octant phase mask, 4 quadrant phase mask
and shaped pupil versions which operate in the NIR (y-K bands). The
PIAA and vector vortex will allow for high contrast imaging down
to an angular separation of 1 λ/D to be reached; a factor of 3
closer in than other extreme AO systems. Making use of the left
over visible light not used by the wavefront sensor is VAMPIRES and
FIRST. These modules are based on aperture masking interferometry and
allow for sub-diffraction limited imaging with moderate contrasts of
~100-1000:1. Both modules have undergone initial testing on-sky and
are set to be fully commissioned by the end of 2014.
---------------------------------------------------------
Title: Looking beyond 30m-class telescopes: the Colossus project
Authors: Kuhn, J. R.; Berdyugina, S. V.; Langlois, M.; Moretto, G.;
Thiébaut, E.; Harlingten, C.; Halliday, D.
2014SPIE.9145E..1GK Altcode:
The exponential growth in exoplanet studies is a powerful reason for
developing very large optical systems optimized for narrow-field
science. Concepts which cross the boundary between fixed aperture
telescopes and interferometers, combined with technologies that decrease
the system moving mass, can violate the cost and mass scaling laws that
make conventional large-aperture telescopes relatively expensive. Here
we describe a concept which breaks this scaling relation in a large
optical/IR system called "Colossus"1.
---------------------------------------------------------
Title: L'-band AGPM vector vortex coronagraph's first light on
LBTI/LMIRCam
Authors: Defrère, D.; Absil, O.; Hinz, P.; Kuhn, J.; Mawet, D.;
Mennesson, B.; Skemer, A.; Wallace, K.; Bailey, V.; Downey, E.;
Delacroix, C.; Durney, O.; Forsberg, P.; Gomez, C.; Habraken, S.;
Hoffmann, W. F.; Karlsson, M.; Kenworthy, M.; Leisenring, J.; Montoya,
M.; Pueyo, L.; Skrutskie, M.; Surdej, J.,
2014SPIE.9148E..3XD Altcode: 2014arXiv1410.6244D
We present the first observations obtained with the L'-band AGPM vortex
coronagraph recently installed on LBTI/LMIRCam. The AGPM (Annular
Groove Phase Mask) is a vector vortex coronagraph made from diamond
subwavelength gratings. It is designed to improve the sensitivity and
dynamic range of high-resolution imaging at very small inner working
angles, down to 0.09 arcseconds in the case of LBTI/LMIRCam in the L'
band. During the first hours on sky, we observed the young A5V star
HR8799 with the goal to demonstrate the AGPM performance and assess
its relevance for the ongoing LBTI planet survey (LEECH). Preliminary
analyses of the data reveal the four known planets clearly at high SNR
and provide unprecedented sensitivity limits in the inner planetary
system (down to the diffraction limit of 0.09 arcseconds).
---------------------------------------------------------
Title: The Constant Size and Shape of the Sun
Authors: Bush, Rock; Emilio, Marcelo; Kuhn, Jeffrey Richard
2014AAS...22421833B Altcode:
Over the last four years, the Helioseismic and Magnetic Imager (HMI)
instrument on the Solar Dynamics Observatory spacecraft has been
measuring the radius and oblateness of the Sun. The primary observations
for the solar radius are full Sun images taken twice per day in the
continuum wing of the 617.3 nm Fe I absorption line. The solar radius
is defined as the mean distance from the center of the Sun to the
inflection point of the limb darkening function. After correcting for
the varying Sun-spacecraft distance and temperature variation of the
optics, the measured solar radius is essentially constant over the
rising phase of the solar cycle.Measurements of the solar oblateness
are obtained twice per year in April and October when the spacecraft is
rotated 360 degrees around the Sun-spacecraft line. HMI observations
taken during these roll maneuvers allow the instrument distortion to
be separated from the solar shape. There is an apparent spring to fall
change which maybe due to seasonal variation of the measurements which
have not been corrected. The long term trend of the solar oblateness,
however, does not show a correlation with the current solar sunspot
cycle.
---------------------------------------------------------
Title: Enabling Technologies for Detecting Life in the Universe:
The Colossus Project
Authors: Kuhn, J.; Berdyugina, S.; Halliday, D.; Harlingten, C.;
Langlois, M.; Moretto, G.
2014ebi..conf.4.19K Altcode:
An international consortium of scientists, engineers, and private
interests formed two in 2012 to develope a large telescope with
the capability of detecting life signatures, and potentially even
Earth-like civilizations, on hundreds of nearby exoplanets. This
"Colossus Telescope" departs from all currently planned large optical
telescope designs in order to achieve the required coronagraphic
performance, angular resolution, and flux sensitivity. As a nearly
filled-aperture, highly redundant-baseline optical and IR imaging
instrument, it has several advantages for studying exoplanets. This
presentation introduces the instrument concept and some strategies
for finding life within about 25pc of the Sun.
---------------------------------------------------------
Title: L'-band AGPM vector vortex coronagraph's first light on
LBTI/LMIRCAM
Authors: Defrère, D.; Absil, O.; Hinz, P.; Mawet, D.; Kuhn, J.; Mawet,
D.; Mennesson, B.; Skemer, A.; Wallace, K.; Bailey, V.; Downey, E.;
Delacroix, C.; Durney, O.; Forsberg, P.; Gomez, C.; Habraken, S.;
Karlsson, M.; Kenworthy, M.; Leisenring, J.; Montoya, M.; Pueyo, L.;
Skrutskie, M.; Surdej, J.
2014ebi..confP4.75D Altcode:
We present the first science observations obtained with the L'-band
AGPM coronagraph recently installed on LBTI/LMIRCAM. The AGPM (Annular
Groove Phase Mask) is a vector vortex coronagraph made from diamond
sub-wavelength gratings tuned to the L'-band. It is designed to improve
the sensitivity and dynamic range of high-resolution imaging at very
small inner working angles, down to 0.09 arcseconds in the case of
LBTI/LMIRCAM in the L'- band. <P />During the first hours on sky,
we observed the young A5V star HR8799 with the goal to obtain the
best sensitivity/contrast ever in the inner region (<1") of the
planetary system. Preliminary analyses of the data reveal the four
known planets clearly at high SNR. The performance of the instrument in
this mode will be presented and compared to straight imaging (without
coronagraph) which is used for the ongoing LBTI planet survey (LEECH,
see abstract by A. Skemer).
---------------------------------------------------------
Title: Detecting extraterrestrial life with the Colossus telescope
using photosynthetic biosignatures
Authors: Berdyugina, S.; Kuhn, J.; Harrington, D.; Moretto, G.;
Langlois, M.; Halliday, D.; Harlingten, C.
2014ebi..confP4.89B Altcode:
We propose to search for life on Earth-like planets in habitable
zones using photosynthesis biosignatures. Many life forms on Earth
process the solar light and utilize it to support their own activity
and to provide a valuable energy source for other life forms. We expect
therefore that photosynthesis is very likely to arise on another planet
and can produce conspicuous biosignatures. We have recently identified
biological polarization effects, e.g., selective light absorption or
scattering by photosynthetic molecules which can be used for remote
detection of extraterrestrial life. Here we present synthetic spectra
and polarization of Earth-like planets with photosynthetic life and
evaluate the sensitivity of the Colossus telescope for their remote
detection in the solar neighborhood.
---------------------------------------------------------
Title: Submicron-AlGaN/GaN MMICs for space applications
Authors: Quay, R.; Waltereit, P.; Kuhn, J.; Bruckner, P.; van
Heijningen, M.; Jukkala, P.; Hirche, K.; Ambacher, O.
2013imsd.conf97533Q Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Investigating the magnetism of brown dwarfs
Authors: Kuzmychov, O.; Berdyugina, S. V.; Harrington, D.; Kuhn, J.
2013MmSAI..84.1127K Altcode: 2013arXiv1309.4617K
We model the spectra of two brown dwarfs observed with the low
resolution spectropolarimeter LRIS (R ∼ 3000, Keck observatory)
during several rotational phases in order to infer their magnetic
properties. The spectra modeled include the intensity signal (Stokes
I/I_c) as well as the polarimetric signals (Stokes Q/I_c, U/I_c and
V/I_c), all coming from the 0-0 vibrational band of the CrH molecule
at ≈ 8610 Å. In order to model the Stokes profiles, we solve a
set of the radiative transfer equations for the CrH transitions in
the presence of an external magnetic field. We present here the upper
limits for the magnetic field strengths for the objects observed, based
on the modeling of the intensity signal I/I_c and the signal-to-noise
information only. The proper modeling of the polarimetric signals,
that requires more careful data reduction, is underway. Nevertheless,
our preliminary results show a hint for kG magnetic fields for both
brown dwarfs, that is in a good agreement with the result obtained
from the simultaneous radio, Halpha and X-Ray observations of one
another radio pulsating brown dwarf.
---------------------------------------------------------
Title: Solar Dark Matter and Dark Energy: How can CryoNIRSP Help?
Authors: Kuhn, J. R.; Scholl, I. F.; Mickey, D. L.
2012ASPC..463..207K Altcode:
ATST will be the world's most expensive optical telescope ever built and
provide the largest jump in our ground-based solar observing capability
since Galileo. It is more than “just a solar telescope” as it will
dominate the solar and stellar science landscape for many years to
come. Given the telescope's ground-breaking new capabilities we should
expect its initial instrumentation to have comparable revolutionary
performance and to expect “discovery” science from the ATST soon
after first light. The CryoNIRSP instrument is one such facility and
the only explicitly coronal instrument designed to take advantage
of the full ATST photometric dynamic range, from typical daytime to
night-time light flux levels. This brief paper summarizes its design
and capabilities.
---------------------------------------------------------
Title: Construction of the Advanced Technology Solar Telescope -
A Progress Report.
Authors: Rimmele, T. R.; Keil, S.; McMullin, J.; Goode, P. R.;
Knoelker, M.; Kuhn, J. R.; Rosner, R.; ATST Team
2012IAUSS...6E.206R Altcode:
The 4m Advance Technology Solar Telescope (ATST) will be the most
powerful solar telescope and the world's leading ground-based resource
for studying solar magnetism that controls the solar wind, flares,
coronal mass ejections and variability in the Sun's output. The ATST
will provide high resolution and high sensitivity observations of the
dynamic solar magnetic fields throughout the solar atmosphere, including
the corona at infrared wavelengths. With its 4 m aperture, ATST will
resolve magnetic features at their intrinsic scales. A high order
adaptive optics system delivers a corrected beam to the initial set of
five state-of-the-art, facility class instrumentation located in the
coude laboratory facility. Photopheric and chromospheric magnetometry
is part of the key mission of four of these instruments. Coronal
magnetometry and spectroscopy will be performed by two of these
instruments at infrared wavelengths. The ATST project has transitioned
from design and development to its construction phase. Site construction
is expected to begin in the first half of 2012. The project has awarded
design and fabrication contracts for major telescope subsystems. A
robust instrument program has been established and all instruments
have passed preliminary design reviews or critical design reviews. A
brief summary of the science goals and observational requirements of
the ATST will be given, followed by a summary of the project status of
the telescope and discussion of the approach to integrating instruments
into the facility.
---------------------------------------------------------
Title: Construction of the Advanced Technology Solar Telescope
Authors: Rimmele, T. R.; Keil, S.; McMullin, J.; Knölker, M.; Kuhn,
J. R.; Goode, P. R.; Rosner, R.; Casini, R.; Lin, H.; Tritschler,
A.; Wöger, F.; ATST Team
2012ASPC..463..377R Altcode:
The 4m Advance Technology Solar Telescope (ATST) will be the most
powerful solar telescope and the world's leading ground-based resource
for studying solar magnetism that controls the solar wind, flares,
coronal mass ejections and variability in the Sun's output. The
project has entered its construction phase. Major subsystems have
been contracted. As its highest priority science driver ATST shall
provide high resolution and high sensitivity observations of the
dynamic solar magnetic fields throughout the solar atmosphere,
including the corona at infrared wavelengths. With its 4m aperture,
ATST will resolve features at 0.″03 at visible wavelengths and
obtain 0.″1 resolution at the magnetically highly sensitive near
infrared wavelengths. A high order adaptive optics system delivers a
corrected beam to the initial set of state-of-the-art, facility class
instrumentation located in the Coudé laboratory facility. The initial
set of first generation instruments consists of five facility class
instruments, including imagers and spectro-polarimeters. The high
polarimetric sensitivity and accuracy required for measurements of
the illusive solar magnetic fields place strong constraints on the
polarization analysis and calibration. Development and construction
of a four-meter solar telescope presents many technical challenges,
including thermal control of the enclosure, telescope structure and
optics and wavefront control. A brief overview of the science goals
and observational requirements of the ATST will be given, followed by a
summary of the design status of the telescope and its instrumentation,
including design status of major subsystems, such as the telescope
mount assembly, enclosure, mirror assemblies, and wavefront correction
---------------------------------------------------------
Title: Eclipse Spectropolarimetry of the ɛ Aurigae System
Authors: Geise, K.; Stencel, R. E.; Manset, N.; Harrington, D.;
Kuhn, J.
2012JAVSO..40..767G Altcode:
The recent eclipse of the enigmatic binary star system, epsilon Aurigae,
offered a special opportunity to explore the role of spectropolarimetry
in discovery of unknown facets of the objects involved. Here we present
spectropolarimetric results for H-alpha, H-beta, Ca I (422.6 nm),
and K I (769.9 nm) based on more than 50 epochs of high dispersion
spectra obtained with the ESPaDOnS instrument at CFHT during 2006-2012.
---------------------------------------------------------
Title: The Precise Solar Shape and Its Variability
Authors: Kuhn, J. R.; Bush, R.; Emilio, M.; Scholl, I. F.
2012Sci...337.1638K Altcode:
The precise shape of the Sun has not been convincingly determined,
despite half a century of modern photoelectric observations. The
expected deviation of the solar-limb shape from a perfect circle is
very small, but such asphericity is sensitive to the Sun’s otherwise
invisible interior conditions, as well as the solar atmosphere. We use
evidence from a long-running experiment based in space to show that,
when analyzed with sufficiently high spatial resolution, the Sun’s
oblate shape is distinctly constant and almost completely unaffected by
the solar-cycle variability seen on its surface. The solar oblateness
is significantly lower than theoretical expectations by an amount that
could be explained by a slower differential rotation in the outer few
percent of the Sun.
---------------------------------------------------------
Title: Advanced Technology Solar Telescope Construction: Progress
Report
Authors: Rimmele, Thomas R.; McMullin, J.; Keil, S.; Goode, P.;
Knoelker, M.; Kuhn, J.; Rosner, R.; ATST Team
2012AAS...22012202R Altcode:
The 4m Advance Technology Solar Telescope (ATST) on Haleakala will be
the most powerful solar telescope and the world’s leading ground-based
resource for studying solar magnetism that controls the solar wind,
flares, coronal mass ejections and variability in the Sun’s
output. The ATST will provide high resolution and high sensitivity
observations of the dynamic solar magnetic fields throughout the solar
atmosphere, including the corona at infrared wavelengths. With its 4
m aperture, ATST will resolve magnetic features at their intrinsic
scales. A high order adaptive optics system delivers a corrected
beam to the initial set of five state-of-the-art, facility class
instrumentation located in the coude laboratory facility. Photopheric
and chromospheric magnetometry is part of the key mission of four
of these instruments. Coronal magnetometry and spectroscopy will be
performed by two of these instruments at infrared wavelengths. The
ATST project has transitioned from design and development to its
construction phase. Site construction is expected to begin in April
2012. The project has awarded design and fabrication contracts for major
telescope subsystems. A robust instrument program has been established
and all instruments have passed preliminary design reviews or critical
design reviews. A brief overview of the science goals and observational
requirements of the ATST will be given, followed by a summary of the
project status of the telescope and discussion of the approach to
integrating instruments into the facility. <P />The National Science
Foundation (NSF) through the National Solar Observatory (NSO) funds
the ATST Project. The NSO is operated under a cooperative agreement
between the Association of Universities for Research in Astronomy,
Inc. (AURA) and NSF.
---------------------------------------------------------
Title: A RHESSI and SDO Campaign Measuring Latitude-dependent Limb
Profiles and Oblateness of the Optical Solar Disk II
Authors: Fivian, Martin; Hudson, H. S.; Lin, R. P.; Bush, R. I.;
Emilio, M.; Kuhn, J. R.; Scholl, I. F.
2012AAS...22020511F Altcode:
The SDO spacecraft conducts special roll maneuvers every 6 months. These
SDO maneuvers enable its HMI instrument to obtain precise observations
of the global structure of the limb. During the SDO roll on 2011
April 6 05:50-12:30 UT, we also successfully obtained RHESSI optical
observations at very high cadence, 128 samples per sec for each
of the three linear CCDs. A second coordinated observation with
optimized parameter settings for RHESSI is planned for the time of
the SDO roll maneuver in April 2012. The data from the two instruments
(RHESSI/SAS and SDO/HMI), give different means for the investigation of
the variation of the solar limb properties as a function of position
angle (latitude). At the normal RHESSI cadence very long integrations
(of order 3 months) are needed to obtain precise limb measurements, but
in this case we are able to report results within the exact time frame
of the SDO roll maneuver. The special RHESSI data rate was about 10,000
times larger than the standard rate and will achieve high precision in
a relatively short time. We will compare these results with our earlier
RHESSI observations (Fivian et al., 2008) and those obtained by Kuhn et
al. (1998) and Emilio et al. (2007) with the earlier MDI roll maneuvers,
and as well as with the most recent analysis of HMI data.
---------------------------------------------------------
Title: Measuring the Solar Radius from Space during the 2003 and
2006 Mercury Transits
Authors: Emilio, M.; Kuhn, J. R.; Bush, R. I.; Scholl, I. F.
2012ApJ...750..135E Altcode: 2012arXiv1203.4898E
The Michelson Doppler Imager (MDI) aboard the Solar and Heliospheric
Observatory observed the transits of Mercury on 2003 May 7 and 2006
November 8. Contact times between Mercury and the solar limb have been
used since the seventeenth century to derive the Sun's size but this
is the first time that high-quality imagery from space, above the
Earth's atmosphere, has been available. Unlike other measurements,
this technique is largely independent of optical distortion. The true
solar radius is still a matter of debate in the literature as measured
differences of several tenths of an arcsecond (i.e., about 500 km)
are apparent. This is due mainly to systematic errors from different
instruments and observers since the claimed uncertainties for a single
instrument are typically an order of magnitude smaller. From the MDI
transit data we find the solar radius to be 960farcs12 ± 0farcs09
(696, 342 ± 65 km). This value is consistent between the transits
and consistent between different MDI focus settings after accounting
for systematic effects.
---------------------------------------------------------
Title: High Resolution Spectropolarimetry of the H<SUB>α</SUB>
Line: Obscured Stars and Absorptive Polarization
Authors: Harrington, D. M.; Kuhn, J. R.
2011ASPC..449..295H Altcode:
The near-star environment around obscured stars is very dynamic. Many
classes of stars show evidence for winds, disks, inflows and outflows
with many phenomena occurring simultaneously. These processes are
involved in stellar evolution, star and planet formation, and influence
the formation and habitability of planets around host stars. Even
for the nearest stars, this region will not be imaged even after
the completion of the next generation of telescopes. Other methods
for measuring the physical properties of circumstellar material must
be developed. The polarization of light across spectral lines is a
signature that contains information about the circumstellar material
on these small spatial scales. We used the HiVIS (R=13 000 to 50 000)
and ESPaDOnS (R=68 000) spectropolarimeters to monitor several classes
of stars on over a hundred nights of observing from 2004-2008. In 10/30
classical Be stars, the traditional broad depolarization morphology is
reproduced, but with some additional absorptive effects in 4 of these
10 stars. In Herbig Ae/Be stars roughly 2/3 of the stars (14/20) with
strong absorptive components (either central or blue-shifted) showed
clear spectropolarimetric signatures typically centered on absorptive
components of the spectral lines. They were typically 0.3% to 2% with
some signatures being variable in time. Post-AGB and RV Tau type evolved
stars showed very strong absorptive polarimetric effects (5/6 PAGB and
4/4 RV Tau) very similar to the Herbig Ae/Be stars. These observations
were inconsistent with the traditional scattering models and inspired
the development of a new explanation of the observed polarization. This
new model, based on optical-pumping, has the potential to provide
direct measurements of the circumstellar gas properties.
---------------------------------------------------------
Title: Does the sun change its shape?
Authors: Kuhn, J. R.; Bush, R. I.; Emilio, M.; Scholl, I.
2011sdmi.confE..39K Altcode:
Its not easy to change the radius or the shape of the Sun. It must
come with a large energy cost and will be difficult to disentangle
from the complicated physics at the boundary between the radiatively
opaque and transparent solar atmosphere. HMI offers great advantages
for measuring the limb physics which we're using to look for solar
cycle variations that could be clues to how the interior changes. This
talk will update the ongoing effort to understand the solar limb better.
---------------------------------------------------------
Title: Deriving Telescope Mueller Matrices Using Daytime Sky
Polarization Observations
Authors: Harrington, David M.; Kuhn, J. R.; Hall, Shannon
2011PASP..123..799H Altcode: 2011arXiv1105.2615H
Telescopes often modify the input polarization of a source so that the
measured circular or linear output state of the optical signal can be
significantly different from the input. This mixing, or polarization
“cross talk,” is defined by the optical system Mueller matrix. We
describe an efficient method here for recovering the input polarization
state of the light and the full 4 × 4 Mueller matrix of the telescope
with an accuracy of a few percent without external masks or telescope
hardware modification. Observations of the bright, highly polarized
daytime sky using the Haleakala 3.7 m AEOS telescope and a coudé
spectropolarimeter demonstrate the technique.
---------------------------------------------------------
Title: A RHESSI And SDO Campaign Measuring Latitude-dependent Limb
ProfilesAnd Oblateness Of The Optical Solar Disk
Authors: Fivian, Martin; Hudson, H. S.; Lin, R. P.; Bush, R. I.;
Emilio, M.; Kuhn, J. R.; Scholl, I. F.
2011SPD....42.1706F Altcode: 2011BAAS..43S.1706F
The SDO spacecraft conducted a special roll maneuver, 2011 April
6 05:50-12:30 UT, to enable its HMI instrument to obtain precise
observations of the global structure of the limb. Similar maneuvers
had been carried out with SOHO for MDI in the past. On this occasion
we also successfully obtained RHESSI optical observations at very
high cadence, 128 samples per sec for each of the three linear
CCDs. The data from the two instrument (RHESSI/SAS and SDO/HMI),
give different means for the investigation of the variation of the
solar limb properties as a function of position angle (latitude). At
the normal RHESSI cadence very long integrations (of order 3 months)
are needed to obtain precise limb measurements, but in this case we
expect to be able to report results within the exact time frame of
the SDO roll maneuver. The special RHESSI data rate was about 10,000
times larger than the standard rate and will achieve high precision in
a relatively short time. We will compare these results with our earlier
RHESSI observations (Fivian et al., 2008) and those obtained by Kuhn et
al. (1998) and Emilio et al. (2007) with the earlier MDI roll maneuvers.
---------------------------------------------------------
Title: Extreme Limb Polarization Measurement From HMI: A Progress
Report
Authors: Scholl, I. F.; Kuhn, J. R.; Bush, R. I.; Emilio, M.
2011ASPC..437..201S Altcode:
We have obtained the first direct measurement of the continuum
polarization near the extreme limb using the Helioseismic Imager (HMI)
on board the Solar Dynamics Observatory (SDO). The polarization is
small (much less than 1%) but easily distinguished from statistical
and systematic noise sources. These measurements differ from previous
attempts to measure small continuum polarization that depended on a
model of line polarization to infer the continuum (cf. Stenflo 2005)
polarization.
---------------------------------------------------------
Title: Using Absorptive Linear Polarization Spectroscopy to Understand
Imbedded Stars
Authors: Kuhn, J. R.; Geiss, B.; Harrington, D. M.
2011ASPC..437..245K Altcode: 2010arXiv1010.0705K
Sensitive measurements of the linearly polarized spectra of stars can
be used to deduce geometric properties of their otherwise unresolved
circumstellar environments. This paper describes some of the evidence
for optical pumping and absorptive linear polarization and explores
some interesting applications of linear spectropolarimetry for obtaining
spatial information from imbedded stars.
---------------------------------------------------------
Title: Solar Polarization Workshop 6
Authors: Kuhn, J. R.; Harrington, D. M.; Lin, H.; Berdyugina, S. V.;
Trujillo-Bueno, J.; Keil, S. L.; Rimmele, T.
2011ASPC..437.....K Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Precision and Resolution in Stellar Spectropolarimetry
Authors: Harrington, D. M.; Kuhn, J. R.
2011ASPC..437..257H Altcode: 2010arXiv1010.0704H
Stellar spectropolarimetry is a relatively new remote sensing tool
for exploring stellar atmospheres and circumstellar environments. We
present the results of our HiVIS survey and a multi-wavelength ESPaDOnS
follow-up campaign showing detectable linear polarization signatures
in many lines for most obscured stars. This survey shows polarization
at and below 0.1% across many lines are common in stars with often
much larger H<SUB>α</SUB> signatures. These smaller signatures
are near the limit of typical systematic errors in most night-time
spectropolarimeters. In an effort to increase our precision and
efficiency for detecting small signals we designed and implemented
the new HiVIS bi-directionally clocked detector synchronized with the
new liquid-crystal polarimeter package. We can now record multiple
independent polarized spectra in a single exposure on identical
pixels and have demonstrated 10<SUP>-4</SUP> relative polarimetric
precision. The new detector allows for the movement of charge on the
device to be synchronized with phase changes in the liquid-crystal
variable retarders at rates of > 5Hz. It also allows for more
efficient observing on bright targets by effectively increasing the
pixel well depth. With the new detector, low and high resolution
modes and polarization calibrations for the instrument and telescope,
we substantially reduce limitations to the precision and accuracy of
this new spectropolarimetric tool.
---------------------------------------------------------
Title: The Search for Molecular Hydrogen in the IR Second Solar
Spectrum
Authors: White, Amanda; Kuhn, J. R.
2011AAS...21743602W Altcode: 2011BAAS...4343602W
Molecular hydrogen in sunspots should be a dominant molecular species
and an important factor in spot dynamics. The rotational and vibrational
transitions of molecular hydrogen are extremely weak in comparison
to the overall intensity spectrum of the sun making the molecule
difficult to observe. Molecular lines, however, are prominent in
the linearly polarized spectrum of the sun, also called the Second
Solar Spectrum. Using the Scatter-free Observatory for Limb Active
Regions and Coronae (SOLAR-C) located on the summit of Haleakala and
a spectropolarimeter, we have observed the linear polarized spectrum
of the sun near the 2.128 micron line of molecular hydrogen and begun
to catalog the second solar spectrum in the IR. <P />This work was
conducted as part of a Research Experience for Undergraduates (REU)
position at the University of Hawai'i's Institute for Astronomy and
funded by the NSF.
---------------------------------------------------------
Title: Properties of the Diffuse Neutral Helium in the Inner
Heliosphere
Authors: Moise, E.; Raymond, J.; Kuhn, J. R.
2010ApJ...722.1411M Altcode:
Sensitive SOLARC imaging spectropolarimetric observations from Haleakala
reveal a diffuse coronal surface brightness in the He I 1083 nm line. A
series of observations suggests that this signal originates from an
"inner source" of neutral helium atoms in the solar corona. Here, we
explore the possibility that this cold coronal component originates from
helium ions that are neutralized by the near-Sun dust and subsequently
excited to the metastable 1s2s <SUP>3</SUP> S state, which then scatters
photons from the solar disk. This picture suggests a deficit of coronal
dust inside about 2-4 R <SUB>sun</SUB> in order to account for both
the flat radial brightness distribution and the small velocity line
width of the observations. We find a strong correlation between the
polarized He brightness and coronal white light brightness that supports
the argument that electronic collisional excitation of the metastable
helium triplet level is responsible for our polarization signal.
---------------------------------------------------------
Title: The Lyot Project Direct Imaging Survey of Substellar
Companions: Statistical Analysis and Information from Nondetections
Authors: Leconte, Jérémy; Soummer, Rémi; Hinkley, Sasha;
Oppenheimer, Ben R.; Sivaramakrishnan, Anand; Brenner, Douglas; Kuhn,
Jeffrey; Lloyd, James P.; Perrin, Marshall D.; Makidon, Russell;
Roberts, Lewis C., Jr.; Graham, James R.; Simon, Michal; Brown,
Robert A.; Zimmerman, Neil; Chabrier, Gilles; Baraffe, Isabelle
2010ApJ...716.1551L Altcode: 2010arXiv1006.3409L
The Lyot project used an optimized Lyot coronagraph with extreme
adaptive optics at the 3.63 m Advanced Electro-Optical System
telescope to observe 86 stars from 2004 to 2007. In this paper, we
give an overview of the survey results and a statistical analysis
of the observed nondetections around 58 of our targets to place
constraints on the population of substellar companions to nearby
stars. The observations did not detect any companion in the substellar
regime. Since null results can be as important as detections,
we analyzed each observation to determine the characteristics of
the companions that can be ruled out. For this purpose, we use a
Monte Carlo approach to produce artificial companions and determine
their detectability by comparison with the sensitivity curve for
each star. All the non-detection results are combined using a
Bayesian approach and we provide upper limits on the population
of giant exoplanets and brown dwarfs for this sample of stars. Our
nondetections confirm the rarity of brown dwarfs around solar-like
stars and we constrain the frequency of massive substellar companions
(M>40 M <SUB>J</SUB>) at orbital separation between and 10 and 50
AU to be lsim20%.
---------------------------------------------------------
Title: On the Constancy of the Solar Radius. III.
Authors: Bush, R. I.; Emilio, M.; Kuhn, J. R.
2010ApJ...716.1381B Altcode:
The Michelson Doppler Imager on board the Solar and Heliospheric
Observatory satellite has operated for over a sunspot cycle. This
instrument is now relatively well understood and provides a nearly
continuous record of the solar radius in combination with previously
developed algorithms. Because these data are obtained from above
Earth's atmosphere, they are uniquely sensitive to possible long-term
changes of the Sun's size. We report here on the first homogeneous,
highly precise, and complete solar-cycle measurement of the Sun's
radius variability. Our results show that any intrinsic changes in
the solar radius that are synchronous with the sunspot cycle must
be smaller than 23 mas peak to peak. In addition, we find that the
average solar radius must not be changing (on average) by more than
1.2 mas yr<SUP>-1</SUP>. If ground- and space-based measurements
are both correct, the pervasive difference between the constancy of
the solar radius seen from space and the apparent ground-based solar
astrometric variability can only be accounted for by long-term changes
in the terrestrial atmosphere.
---------------------------------------------------------
Title: Achromatizing a Liquid-Crystal Spectropolarimeter: Retardance
vs. Stokes-Based Calibration of HiVIS
Authors: Harrington, D. M.; Kuhn, J. R.; Sennhauser, C.; Messersmith,
E. J.; Thornton, R. J.
2010PASP..122..420H Altcode: 2010arXiv1002.1409H
Astronomical spectropolarimeters can be subject to many sources
of systematic error that limit the precision and accuracy of
the instrument. We present a calibration method for observing
high-resolution polarized spectra using chromatic liquid-crystal
variable retarders (LCVRs). These LCVRs allow for polarimetric
modulation of the incident light without any moving optics at
frequencies ≥10 Hz. We demonstrate a calibration method using pure
Stokes input states that enables an achromatization of the system. This
Stokes-based deprojection method reproduces input polarization
even though highly chromatic instrument effects exist. This process
is first demonstrated in a laboratory spectropolarimeter where we
characterize the LCVRs and show example deprojections. The process
is then implemented on the newly upgraded HiVIS spectropolarimeter
on the 3.67 m Advanced Electro-Optical System (AEOS) telescope. The
HiVIS spectropolarimeter has also been expanded to include broadband
full-Stokes spectropolarimetry using achromatic wave plates in addition
to the tunable full-Stokes polarimetric mode using LCVRs. These two new
polarimetric modes in combination with a new polarimetric calibration
unit provide a much more sensitive polarimetric package with greatly
reduced systematic error.
---------------------------------------------------------
Title: FIRS: a new instrument for photospheric and chromospheric
studies at the DST.
Authors: Jaeggli, S. A.; Lin, H.; Mickey, D. L.; Kuhn, J. R.; Hegwer,
S. L.; Rimmele, T. R.; Penn, M. J.
2010MmSAI..81..763J Altcode:
The simultaneous observation of select spectral lines at optical and
infrared wavelengths allows for the determination of the magnetic
field at several photospheric and chromospheric heights and thus
the 3D magnetic field gradient in the solar atmosphere. The Facility
Infrared Spectropolarimeter (FIRS) is a newly completed, multi-slit,
dual-beam spectropolarimeter installed at the Dunn Solar Telescope
(DST) at Sacramento Peak (NSO/SP). Separate optics and polarimeters
simultaneously observe two band-passes at visible and infrared
wavelengths with a choice of two modes: the Fe I 6302 Å and 15648 Å
lines in the photosphere; or the Fe I 6302 Å and He I 10830 Å line
in the photosphere and high chromosphere, respectively. FIRS can also
operate simultaneously with a white light camera, G-band imager, and
the Interferometric Bi-dimensional Spectrometer (IBIS) observing the
mid-chromospheric Ca II 8542 Å line. The instrument uses four parallel
slits to sample four slices of the solar surface simultaneously to
achieve fast, diffraction-limited precision imaging spectropolarimetry,
enabling the study of MHD phenomena with short dynamic time scales.
---------------------------------------------------------
Title: The Near-Star Environment: Spectropolarimetry of Herbig
Ae/Be Stars
Authors: Harrington, D. M.; Kuhn, J. R.
2009ASPC..420...77H Altcode: 2007arXiv0711.2604H
The near-star environment around young stars is very dynamic with winds,
disks, and outflows. These processes are involved in star and planet
formation, and influence the formation and habitability of planets
around host stars. Even for the closest young stars, this will not be
imaged even after the completion of the next generation of telescopes
decades from now and other proxies must be used. The polarization of
light across individual spectral lines is such a proxy that contains
information about the geometry and density of circumstellar material on
these small spatial scales. We have recently built a high-resolution
spectropolarimeter (R 13000 to 50000) for the HiVIS spectrograph on
the 3.67m AEOS telescope. We used this instrument to monitor several
young intermediate-mass stars over many nights. These observations show
clear spectropolarimetric signatures typically centered on absorptive
components of the spectral lines, with some signatures variable in
time. The survey also confirms the large spectroscopic variability
in these stars on timescales of minutes to months, and shows the
dynamic bullets and streamers in the stellar winds. These observations
were largely inconsistent with the traditional scattering models and
inspired the development of a new explanation of their polarization,
based on optical-pumping, that has the potential to provide direct
measurements of the circumstellar gas properties.
---------------------------------------------------------
Title: Line-profile Variability from Tidal Flows in Alpha Virginis
(Spica)
Authors: Harrington, David; Koenigsberger, Gloria; Moreno, Edmundo;
Kuhn, Jeffrey
2009ApJ...704..813H Altcode: 2009arXiv0908.3336H
We present the results of high precision, high-resolution (R ~ 68,000)
optical observations of the short-period (4 days) eccentric binary
system Alpha Virginis (Spica) showing the photospheric line-profile
variability that in this system can be attributed to non-radial
pulsations driven by tidal effects. Although scant in orbital-phase
coverage, the data provide signal-to-noise ratio > 2000 line profiles
at full spectral resolution in the wavelength range Δλ4000-8500 Å,
allowing a detailed study of the night-to-night variability as well as
changes that occur on ~2 hr timescale. Using an ab initio theoretical
calculation, we show that the line-profile variability can arise as
a natural consequence of surface flows that are induced by the tidal
interaction.
---------------------------------------------------------
Title: New Solar System Researches expected by a New Telescope
Project at Mt. Haleakala, Hawaii
Authors: Kagitani, Masato; Okano, S.; Kasaba, Y.; Kuhn, J.;
Berdyugina, S.
2009DPS....41.4509K Altcode:
We Tohoku University starts the project for the new ground-based
telescope dedicated to planets and exoplanets, in collaboration
with the Institute for Astronomy of University of Hawaii(IfA/UH)
and ETH Zurich. <P />The summit of Mt. Haleakala in Maui, Hawaii is
one of the best sites with clear skies, good seeing, and low humidity
conditions as well as good accessibility despite its high altitude
(elv. 3,000m). Haleakala High Altitude Observatory is operated by
IfA/UH, and we have been making observation of planets there since
2000. <P />Currently, our observation facility consists of a 40cm
telescope. We have been making observations of faint atmospheric and
plasma features around bright planets, Io plasma torus, Mercury and
Lunar sodium tail, and so on. Atmospheric escapes from Mars and Venus,
the exoplanets close to mother stars are also possible future important
topics. When we try to observe those faint emissions surrounding the
bright objects, intense scattered light causes a serious problem. The
new telescope shall avoid the diffraction due to a spider structure
that holds a secondary mirror and to minimize the scattered light
from mirror surfaces as far as possible. Such telescope with a wide
dynamic range dedicated to planetary and exoplanetary sciences does
not exist yet. <P />The project, called PLANETS (Poralized Light
from Atmospheres of Nearby Extra Terrestrial Planets), develops a new
telescope (tentatively named as JHET; Japan Hawaii Europe Telescope)
which consists of an off-axis primary mirror with a diameter of
1.8m, and Gregorian optics on an equatorial mount. State-of-art
adaptive optics and masking technologies will also be adopted to
eliminate the scattering light. This telescope will enables us to do
spectro-polarimetric observations and faint plasma and atmospheres
around the bright bodies. <P />We will introduce the progress of our
ground-based observations and the future plan involving the wide area
of the international communities.
---------------------------------------------------------
Title: Speckle Suppression Through Dual Imaging Polarimetry, and a
Ground-based Image of the HR 4796A Circumstellar Disk
Authors: Hinkley, Sasha; Oppenheimer, Ben R.; Soummer, Rémi; Brenner,
Douglas; Graham, James R.; Perrin, Marshall D.; Sivaramakrishnan,
Anand; Lloyd, James P.; Roberts, Lewis C., Jr.; Kuhn, Jeffrey
2009ApJ...701..804H Altcode: 2009arXiv0906.3010H
We demonstrate the versatility of a dual imaging polarimeter working
in tandem with a Lyot coronagraph and adaptive optics to suppress
the highly static speckle noise pattern—the greatest hindrance
to ground-based direct imaging of planets and disks around nearby
stars. Using a double difference technique with the polarimetric data,
we quantify the level of speckle suppression, and hence improved
sensitivity, by placing an ensemble of artificial faint companions
into real data, with given total brightness and polarization. For
highly polarized sources within 0farcs5, we show that we achieve 3
to 4 mag greater sensitivity through polarimetric speckle suppression
than simply using a coronagraph coupled to a high-order adaptive optics
system. Using such a polarimeter with a classical Lyot coronagraph at
the 3.63 m Advanced Electro-Optical System telescope, we have obtained
a 6.5σ detection in the H band of the 76 AU diameter circumstellar
debris disk around the star HR 4796A. Our data represent the first
definitive ground-based near-IR polarimetric image of the HR 4796A
debris disk and clearly show the two outer ansae of the disk, evident
in Hubble Space Telescope NICMOS/STIS imaging. Comparing our peak
linearly polarized flux with the total intensity in the lobes as
observed by NICMOS, we derive a lower limit to the fractional linear
polarization of >29% caused by dust grains in the disk. In addition,
we fit simple morphological models of optically thin disks to our data
allowing us to constrain the dust disk scale height (2.5<SUP>+5.0</SUP>
<SUB>-1.3</SUB> AU) and scattering asymmetry parameter (g = langcos
θrang = 0.20<SUP>+.07</SUP> <SUB>-.10</SUB>). These values are
consistent with several lines of evidence suggesting that the HR 4796A
disk is dominated by a micron-sized dust population, and are indeed
typical of disks in transition between those surrounding the Herbig
Ae stars to those associated with Vega-like stars.
---------------------------------------------------------
Title: Ubiquitous Hα-Polarized Line Profiles: Absorptive
Spectropolarimetric Effects and Temporal Variability in Post-AGB,
Herbig Ae/Be, and Other Stellar Types
Authors: Harrington, D. M.; Kuhn, J. R.
2009ApJ...695..238H Altcode: 2008arXiv0812.2598H
We show here that the absorptive Hα polarized line profile previously
seen in many Herbig Ae/Be (HAeBe) stars is a nearly ubiquitous feature
of other types of embedded or obscured stars. This characteristic 1%
linear polarization variation across the absorptive part of the Hα
line is seen in post-AGB stars as well as RV Tau, δ Scuti, and other
types. Each of these stars shows evidence of obscuration by intervening
circumstellar hydrogen gas and the polarization effect is in the
absorptive component, consistent with an optical pumping model. We
present ESPaDOnS spectropolarimetric observations of nine post-AGB
and RV Tau types in addition to many multi-epoch HiVIS observations
of these targets. We find significant polarization changes across
the Hα line in 8/9 stars with polarization amplitudes of 0.5% to
over 3% (5/6 post-AGB and 3/3 RV Tau). In all but one of these, the
polarization change is dominated by the absorptive component of the
line profile. There is no evidence that subclasses of obscured stars
showing stellar pulsations (RV Tau for post-AGB stars and δ Scuti for
Herbig Ae/Be stars) show significant spectropolarimetric differences
from the main class. Significant temporal variability is evident from
both HiVIS and ESPaDOnS data for several stars presented here: 89 Her,
AC Her, SS Lep, MWC 120, AB Aurigae, and HD144668. The morphologies
and temporal variability are comparable to existing large samples of
Herbig Ae/Be and Be type stars. Since post-AGB stars have circumstellar
gas that is very different from Be stars, we discuss these observations
in the context of their differing environments.
---------------------------------------------------------
Title: Spectropolarimetric Observations of Herbig Ae/Be
Stars. II. Comparison of Spectropolarimetric Surveys: Haebe, Be and
Other Emission-Line Stars
Authors: Harrington, D. M.; Kuhn, J. R.
2009ApJS..180..138H Altcode: 2008arXiv0809.3849H
The polarization of light across individual spectral lines contains
information about the circumstellar environment on very small
spatial scales. We have obtained a large number of high-precision,
high-resolution spectropolarimetric observations of Herbig Ae/Be,
Classical Be and other emission-line stars collected on 117 nights
of observations with the Hi-Resolution Visible spectropolarimeter at
a resolution of R = 13, 000 on the 3.67 m Advanced Electro-Optical
System telescope. We also have many observations from the ESPaDOnS
spectropolarimeter at a resolution of R = 68, 000 on the 3.6 m
Canada-France-Hawaii Telescope. In roughly ~2/3 of the so-called
"windy" or "disky" Herbig Ae/Be stars, the detected H<SUB>α</SUB>
linear polarization varies from our typical detection threshold near
0.1% to over 2%. In all but one HAe/Be star, the detected polarization
effect is not coincident with the H<SUB>α</SUB> emission peak but
is detected in and around the obvious absorptive part of the line
profile. The qu-loops are dominated by the polarization in this
absorptive region. In several stars, the polarization varies in time
mostly in the absorptive component and is not necessarily tied to
corresponding variations in intensity. This is a new result not seen
at lower resolution. In the Be and emission-line stars, ten out of a
sample of 30 show a typical broad depolarization effect but four of
these ten show weaker effects only visible at high resolution. Another
five of 30 show smaller amplitude, more complex signatures. Six stars
of alternate classification showed large amplitude (1%-3%) absorptive
polarization effects. These detections are largely inconsistent with
the traditional disk-scattering and depolarization models.
---------------------------------------------------------
Title: Spectropolarimetry of the Deep Impact Target Comet 9P/Tempel
1 with HiVIS
Authors: Harrington, D. M.; Meech, K. J.; Kolokolova, L.; Kuhn, J. R.;
Whitman, K.
2009diwo.conf..155H Altcode: 2007astro.ph..3335H
Spectropolarimetry of the Deep Impact target, comet 9P/ Tempel 1,
was performed during the impact event on July 4th, 2005 with the HiVIS
Spectropolarimeter and the AEOS 3.67-m telescope on Haleakala, Maui. We
observed atypical polarization spectra that changed significantly in
the few hours after the impact. The polarization is sensitive to the
geometry, size and composition of the scattering particles. Our first
measurement, beginning 8 minutes after impact and centered at 6:30UT,
showed a polarization of 4% at 650 nm falling to 3% at 950 nm. The next
observation, centered an hour later, showed a polarization of 7% at 650
nm falling to 2% at 950nm. This corresponds to a spectropolarimetric
gradient, or slope, of -0.9% per 1000Å 40 minutes after impact,
decreasing to a slope of -2.3% per 1000Å 75 minutes after impact. Both
are atypical blue polarization slopes. The polarization values of 4 and
7% at 650 nm are typical for comets at this scattering angle, whereas
the low polarization of 2 and 3% at 950 nm is not. This, combined
with the IR spectroscopy performed by a number of observers during
the event, suggests an increase in size, number, and crystallinity of
the individual silicate particles (monomers) that are a constituant
of the dust particles (aggregates) in the ejecta.
---------------------------------------------------------
Title: Spectropolarimetric Observations of the Helium 10830 Å Line:
A Search for the Signature of Optical Pumping
Authors: Goldbaum, Nathan Jonathan; Kuhn, J. R.
2009AAS...21349204G Altcode: 2009BAAS...41..472G
In order to characterize the center-to-limb and latitudinal variation of
the polarization of the He I 10830 Å line we observed the limb of the
sun at several position angles using the Scatter-Free Observatory for
Limb Active Regions and Coronae (SOLARC), an imaging spectropolarimeter
located on the summit of Haleakala, Maui. The data was reduced and
analyzed to produce profiles of the magnitude of the Stokes Q/I and
U/I signals as a function of latitude and solar radius. Modeling of
the observed profiles should allow us to detect whether the observed
linear polarization signal is due entirely to scattering polarization
or possibly includes absorptively polarized light transmitted through
an optically pumped gas. This work was conducted as part of a Research
Experience for Undergraduates (REU) position at the University of
Hawaii's Institute for Astronomy and funded by the NSF
---------------------------------------------------------
Title: Measuring Electron Temperature and Flow Speed using Thomson
Scattered Emission from the Corona Observed with the Solar-C
Coronagraph
Authors: Davila, J. M.; Reginald, N.; St. Cyr, O. C.; Kuhn, J.
2008AGUFMSH11A..05D Altcode:
A method for measuring the density, temperature, and velocity of
coronal electrons was proposed by Reginald and Davila (2000) based on
an extension the Thomson scattering theory of Cram (1976) to include
flows. In this method the electron density is measured in the usual
way (e.g. in LASCO or MkIV coronagraph images) by observing the total
coronal intensity. The electron temperature and flow speed are obtained
by obtaining ratios of spectral intensity measured in 50 A passbands
or by fitting a portion of the spectrum to coronal models. Observations
during the total solar eclipse of 2000 near Lusaka, Zambia demonstrated
the feasibility of the method (Reginald et. al., 2003) using the first
generation Multi-Aperture Coronal Spectrometer (MACS-1) instrument, and
with the second-generation MACS in Libya in 2006 reasonable temperature
and flow speeds were obtained. In this paper we continue this work by
reporting on the results of new observations taken from the ground at
the Solar-C coronagraph. Although eclipse measurements provide the best
observation (nearly free of scattered light but with limited duration),
the Solar-C coronagraph observations allowed several days of nearly
continuous observation from which the repeatability and accuracy of the
measurement could be determined. To deal with the increased atmospheric
scatter, observations at Solar-C were done in polarized brightness
(pB). Results will be reported in this talk.
---------------------------------------------------------
Title: Electroexcitation of the Roper resonance for
1.7<Q<SUP>2</SUP><4.5GeV<SUP>2</SUP> in e→p→enπ<SUP>+</SUP>
Authors: Aznauryan, I. G.; Burkert, V. D.; Kim, W.; Park, K.; Adams,
G.; Amaryan, M. J.; Ambrozewicz, P.; Anghinolfi, M.; Asryan, G.;
Avakian, H.; Bagdasaryan, H.; Baillie, N.; Ball, J. P.; Baltzell,
N. A.; Barrow, S.; Batourine, V.; Battaglieri, M.; Bedlinskiy, I.;
Bektasoglu, M.; Bellis, M.; Benmouna, N.; Berman, B. L.; Biselli,
A. S.; Blaszczyk, L.; Bonner, B. E.; Bookwalter, C.; Bouchigny, S.;
Boiarinov, S.; Bradford, R.; Branford, D.; Briscoe, W. J.; Brooks,
W. K.; Bültmann, S.; Butuceanu, C.; Calarco, J. R.; Careccia, S. L.;
Carman, D. S.; Casey, L.; Cazes, A.; Chen, S.; Cheng, L.; Cole, P. L.;
Collins, P.; Coltharp, P.; Cords, D.; Corvisiero, P.; Crabb, D.; Crede,
V.; Cummings, J. P.; Dale, D.; Dashyan, N.; de Masi, R.; de Vita, R.;
de Sanctis, E.; Degtyarenko, P. V.; Denizli, H.; Dennis, L.; Deur,
A.; Dhamija, S.; Dharmawardane, K. V.; Dhuga, K. S.; Dickson, R.;
Djalali, C.; Dodge, G. E.; Donnelly, J.; Doughty, D.; Dugger, M.;
Dytman, S.; Dzyubak, O. P.; Egiyan, H.; Egiyan, K. S.; Fassi, L. El;
Elouadrhiri, L.; Eugenio, P.; Fatemi, R.; Fedotov, G.; Feldman, G.;
Feuerbach, R. J.; Forest, T. A.; Fradi, A.; Funsten, H.; Gabrielyan,
M. Y.; Garçon, M.; Gavalian, G.; Gevorgyan, N.; Gilfoyle, G. P.;
Giovanetti, K. L.; Girod, F. X.; Goetz, J. T.; Gohn, W.; Golovatch,
E.; Gonenc, A.; Gordon, C. I. O.; Gothe, R. W.; Graham, L.; Griffioen,
K. A.; Guidal, M.; Guillo, M.; Guler, N.; Guo, L.; Gyurjyan, V.;
Hadjidakis, C.; Hafidi, K.; Hafnaoui, K.; Hakobyan, H.; Hakobyan,
R. S.; Hanretty, C.; Hardie, J.; Hassall, N.; Heddle, D.; Hersman,
F. W.; Hicks, K.; Hleiqawi, I.; Holtrop, M.; Hyde, C. E.; Ilieva, Y.;
Ireland, D. G.; Ishkhanov, B. S.; Isupov, E. L.; Ito, M. M.; Jenkins,
D.; Jo, H. S.; Johnstone, J. R.; Joo, K.; Juengst, H. G.; Kalantarians,
N.; Keller, D.; Kellie, J. D.; Khandaker, M.; Kim, K. Y.; Klein, A.;
Klein, F. J.; Klimenko, A. V.; Kossov, M.; Krahn, Z.; Kramer, L. H.;
Kubarovsky, V.; Kuhn, J.; Kuhn, S. E.; Kuleshov, S. V.; Kuznetsov,
V.; Lachniet, J.; Laget, J. M.; Langheinrich, J.; Lawrence, D.; Lee,
T.; Li, Ji; Lima, A. C. S.; Livingston, K.; Lu, H. Y.; Lukashin,
K.; MacCormick, M.; Markov, N.; Mattione, P.; McAleer, S.; McKinnon,
B.; McNabb, J. W. C.; Mecking, B. A.; Mehrabyan, S.; Melone, J. J.;
Mestayer, M. D.; Meyer, C. A.; Mibe, T.; Mikhailov, K.; Minehart, R.;
Mirazita, M.; Miskimen, R.; Mokeev, V.; Morand, L.; Moreno, B.; Moriya,
K.; Morrow, S. A.; Moteabbed, M.; Mueller, J.; Munevar, E.; Mutchler,
G. S.; Nadel-Turonski, P.; Nasseripour, R.; Niccolai, S.; Niculescu,
G.; Niculescu, I.; Niczyporuk, B. B.; Niroula, M. R.; Niyazov,
R. A.; Nozar, M.; O'Rielly, G. V.; Osipenko, M.; Ostrovidov, A. I.;
Park, S.; Pasyuk, E.; Paterson, C.; Pereira, S. Anefalos; Philips,
S. A.; Pierce, J.; Pivnyuk, N.; Pocanic, D.; Pogorelko, O.; Polli,
E.; Popa, I.; Pozdniakov, S.; Preedom, B. M.; Price, J. W.; Prok,
Y.; Protopopescu, D.; Qin, L. M.; Raue, B. A.; Riccardi, G.; Ricco,
G.; Ripani, M.; Ritchie, B. G.; Rosner, G.; Rossi, P.; Rowntree, D.;
Rubin, P. D.; Sabatié, F.; Saini, M. S.; Salamanca, J.; Salgado, C.;
Santoro, J. P.; Sapunenko, V.; Schott, D.; Schumacher, R. A.; Serov,
V. S.; Sharabian, Y. G.; Sharov, D.; Shaw, J.; Shvedunov, N. V.;
Skabelin, A. V.; Smith, E. S.; Smith, L. C.; Sober, D. I.; Sokhan,
D.; Stavinsky, A.; Stepanyan, S. S.; Stepanyan, S.; Stokes, B. E.;
Stoler, P.; Strakovsky, I. I.; Strauch, S.; Suleiman, R.; Taiuti, M.;
Takeuchi, T.; Tedeschi, D. J.; Tkabladze, A.; Tkachenko, S.; Todor,
L.; Tur, C.; Ungaro, M.; Vineyard, M. F.; Vlassov, A. V.; Watts,
D. P.; Weinstein, L. B.; Weygand, D. P.; Williams, M.; Wolin, E.;
Wood, M. H.; Yegneswaran, A.; Yun, J.; Yurov, M.; Zana, L.; Zhang,
B.; Zhang, J.; Zhao, B.; Zhao, Z. W.
2008PhRvC..78d5209A Altcode: 2008arXiv0804.0447A
The helicity amplitudes of the electroexcitation of the Roper resonance
are extracted for 1.7<Q<SUP>2</SUP><4.5GeV<SUP>2</SUP> from
recent high precision JLab-CLAS cross section and longitudinally
polarized beam asymmetry data for π<SUP>+</SUP> electroproduction
on protons at W=1.15-1.69 GeV. The analysis is made using two
approaches, dispersion relations and a unitary isobar model,
which give consistent Q<SUP>2</SUP> behavior of the helicity
amplitudes for the γ<SUP>*</SUP>p→N(1440)P<SUB>11</SUB>
transition. It is found that the transverse helicity amplitude
A<SUB>1/2</SUB>, which is large and negative at Q<SUP>2</SUP>=0,
becomes large and positive at Q<SUP>2</SUP>≃2GeV<SUP>2</SUP>,
and then drops slowly with Q<SUP>2</SUP>. The longitudinal
helicity amplitude S<SUB>1/2</SUB>, which was previously found
from CLAS e→p→epπ<SUP>0</SUP>,enπ<SUP>+</SUP> data to be
large and positive at Q<SUP>2</SUP>=0.4,0.65GeV<SUP>2</SUP>,
drops with Q<SUP>2</SUP>. Available model predictions for
γ<SUP>*</SUP>p→N(1440)P<SUB>11</SUB> allow us to conclude that these
results provide strong evidence in favor of N(1440)P<SUB>11</SUB> as
a first radial excitation of the 3q ground state. The results of the
present paper also confirm the conclusion of our previous analysis
for Q<SUP>2</SUP><1 GeV<SUP>2</SUP> that the presentation of
N(1440)P<SUB>11</SUB> as a qG3 hybrid state is ruled out.
---------------------------------------------------------
Title: High Resolution Spectropolarimetry of the H-alpha Line:
Obscured Stars and Absorptive Polarization
Authors: Harrington, D. M.; Kuhn, J. R.
2008arXiv0809.3297H Altcode:
The near-star environment around obscured stars is very dynamic. Many
classes of stars show evidence for winds, disks, inflows and outflows
with many phenomena occurring simultaneously. These processes are
involved in stellar evolution, star and planet formation, and influence
the formation and habitability of planets around host stars. Even
for the nearest stars, this region will not be imaged even after
the completion of the next generation of telescopes. Other methods
for measuring the physical properties of circumstellar material must
be developed. The polarization of light across spectral lines is a
signature that contains information about the circumstellar material
on these small spatial scales. We used the HiVIS (R=13000 to 50000)
and ESPaDOnS (R=68000) spectropolarimeters to monitor several classes
of stars on over a hundred nights of observing from 2004-2008. In 10/30
classical Be stars, the traditional broad depolarization morphology is
reproduced, but with some additional absorptive effects in 4 of these
10 stars. In Herbig Ae/Be stars roughly 2/3 of the stars (14/20) with
strong absorptive components (either central or blue-shifted) showed
clear spectropolarimetric signatures typically centered on absorptive
components of the spectral lines. They were typically 0.3% to 2% with
some signatures being variable in time. Post-AGB and RV-Tau type evolved
stars showed very strong absorptive polarimetric effects (5/6 PAGB and
4/4 RVTau) very similar to the Herbig Ae/Be stars. These observations
were inconsistent with the traditional scattering models and inspired
the development of a new explanation of the observed polarization. This
new model, based on optical-pumping, has the potential to provide
direct measurements of the circumstellar gas properties.
---------------------------------------------------------
Title: Inner Source Diffuse Helium Observations
Authors: Moise, E.; Kuhn, J.; Raymond, J.; Armstrong, J. D.
2008ESPM...12.2.88M Altcode:
Sensitive SOLARC imagining spectropolarimetric observations from
Haleakala reveal a diffuse coronal surface brightness in the He I
1083nm line. A series of observations obtained during the last two
years suggests that this signal originates from an "inner source"
of neutral helium atoms in the solar corona. We argue here that this
cold coronal component is likely to originate from the near-sun dust,
and that there is a deficit of coronal dust close to the Sun.
---------------------------------------------------------
Title: The Solar-System-Scale Disk around AB Aurigae
Authors: Oppenheimer, Ben R.; Brenner, Douglas; Hinkley, Sasha;
Zimmerman, Neil; Sivaramakrishnan, Anand; Soummer, Remi; Kuhn, Jeffrey;
Graham, James R.; Perrin, Marshall; Lloyd, James P.; Roberts, Lewis
C., Jr.; Harrington, David M.
2008ApJ...679.1574O Altcode: 2008arXiv0803.3629O
The young star AB Aurigae is surrounded by a complex combination of
gas-rich and dust-dominated structures. The inner disk, which has not
been studied previously at sufficient resolution and imaging dynamic
range, seems to contain very little gas inside a radius of least 130 AU
from the star. Using adaptive optics coronagraphy and polarimetry, we
have imaged the dust in an annulus between 43 and 302 AU from the star,
a region never seen before. An azimuthal gap in an annulus of dust at
a radius of 102 AU, along with a clearing at closer radii inside this
annulus, suggests the formation of at least one small body at an orbital
distance of ~100 AU. This structure seems consistent with crude models
of mean motion resonances or accumulation of material at two of the
Lagrange points relative to the putative object and the star. We also
report a low significance detection of a point source in this outer
annulus of dust. This source may be an overdensity in the disk due to
dust accreting onto an unseen companion. An alternate interpretation
suggests that the object's mass is between 5 and 37 times the mass of
Jupiter. The results have implications for circumstellar disk dynamics
and planet formation.
---------------------------------------------------------
Title: The Facility IR Spectropolarimeter for the Dunn Solar Telescope
Authors: Jaeggli, S. A.; Lin, H.; Mickey, D. L.; Kuhn, J. R.; Hegwer,
S. L.; Rimmele, T. R.; Penn, M. J.
2008AGUSMSH31A..11J Altcode:
The Facility IR Spectropolarimeter(FIRS) is a multi-slit
spectropolarimeter designed for the Dunn Solar Telescope (DST) at the
National Solar Observatory on Sacramento Peak (NSO/SP) in New Mexico to
study magnetism on the solar surface. The instrument samples adjacent
slices of the solar surface using four parallel slits to achieve high
cadence, diffraction-limited, precision imaging-spectropolarimetry. Due
to the versatile, multi-armed design of the spectrograph, up to
four spectral lines at visible and infrared wavelengths, covering
four different heights in the solar atmosphere, can be observed
simultaneously. In this poster-paper we will describe the design,
capabilities, and performance of the instrument.
---------------------------------------------------------
Title: First Direct Detection of Magnetic Fields in Starspots and
Stellar Chromospheres
Authors: Berdyugina, S. V.; Fluri, D. M.; Afram, N.; Suwald, F.;
Petit, P.; Arnaud, J.; Harrington, D. M.; Kuhn, J. R.
2008ASPC..384..175B Altcode: 2008csss...14..175B; 2007astro.ph..3559B
Here we report on the first detection of circular polarization in
molecular lines formed in cool magnetic regions (starspots) and in
chromospheric emission lines formed in hot plages on the surfaces
of active stars. <P />Our survey of G-K-M stars included young
main-sequence dwarfs and RS~CVn-type giants and subgiants. All
stars were found to possess surface magnetic fields producing
Stokes V LSD signals in atomic lines of 0.05% to 0.5%. Several stars
clearly showed circular polarization in molecular lines of 0.1% to
1%. The molecular Stokes V signal is reminiscent of that observed in
sunspots. Chromospheric magnetic fields were detected on most active
targets in Stokes~V profiles of emission lines with peak polarization
up to 2%. The observed molecular circular polarization on M dwarfs
indicates single-polarity magnetic fields covering at least 10% of
the stellar disk. Smaller signals on K stars imply that their magnetic
fields are apparently weaker, more entangled than on M dwarfs, or more
diluted by the bright photosphere.
---------------------------------------------------------
Title: Spectropolarimetric Observations of Herbig Ae/Be
Stars. I. HiVIS Spectropolarimetric Calibration and Reduction
Techniques
Authors: Harrington, D. M.; Kuhn, J. R.
2008PASP..120...89H Altcode: 2007arXiv0711.2327H
Using the High-Resolution Visible Spectrograph (HiVIS)
spectropolarimeter built for the Haleakala 3.7 m Advanced
Electro-optical System (AEOS) telescope in Hawaii, we are collecting
a large number of high precision spectropolarimetric observations of
stars. In order to precisely measure very small polarization changes,
we have performed a number of polarization calibration techniques on the
AEOS telescope and HiVIS spectrograph. We have extended our dedicated
IDL reduction package and have performed some hardware upgrades to
the instrument. We have also used the ESPaDOnS spectropolarimeter on
CFHT to verify the HiVIS results with back-to-back observations of
MWC 361 and HD 163296. Comparison of this and other HiVIS data with
stellar observations from the Intermediate-dispersion Spectroscopic
and Imaging System (ISIS) and William-Wehlau (WW) spectropolarimeters
in the literature further shows the usefulness of this instrument.
---------------------------------------------------------
Title: Curvature adaptive optics and low light imaging
Authors: Ftaclas, C.; Chun, M.; Kuhn, J.; Ritter, J.
2008amos.confE..20F Altcode:
We review the basic approach of curvature adaptive optics (AO) and
show how its many advantages arise. A curvature wave front sensor
(WFS) measures exactly what a curvature deformable mirror (DM)
generates. This leads to the computational and operational simplicity
of a nearly diagonal control matrix. The DM automatically reconstructs
the wave front based on WFS curvature measurements. Thus, there is no
formal wave front reconstruction. This poses an interesting challenge
to post-processing of AO images. Physical continuity of the DM and
the reconstruction of phase from wave front curvature data assure
that each actuated region of the DM corrects local phase, tip-tilt
and focus. This gain in per-channel correction efficiency, combined
with the need for only one pixel per channel detector reads in the WFS
allows the use of photon counting detectors for wave front sensing. We
note that the use of photon counting detectors implies penalty-free
combination of correction channels either in the WFS or on the DM. This
effectively decouples bright and faint source performance in that one
no longer predicts the other. The application of curvature AO to the
low light moving target detection problem, and explore the resulting
challenges to components and control systems. Rapidly moving targets
impose high-speed operation posing new requirements unique to curvature
components. On the plus side, curvature wave front sensors, unlike
their Shack-Hartmann counterparts, are tunable for optimum sensitivity
to seeing and we are examining autonomous optimization of the WFS to
respond to rapid changes in seeing.
---------------------------------------------------------
Title: Observing Interstellar Neutral Helium from the Ground
Authors: Moise, E.; Kuhn, J.
2007AGUFMSH14A1698M Altcode:
Cool neutral Helium is now being observed near the Sun. Routinely from
sensitive IR spectropolarimetry data using SOLARC at Haleakala and from
eclipses, observations reveal scattered photospheric light at 1083nm
from He I far above the solar limb. Here we report on observations of
this transient coronal constituent that help to understand whether
this comes from the coronal "inner source" or from the interstellar
Helium wind.
---------------------------------------------------------
Title: Detection of an Extended Near-Sun Neutral Helium Cloud from
Ground-based Infrared Coronagraph Spectropolarimetry
Authors: Kuhn, J. R.; Arnaud, J.; Jaeggli, S.; Lin, H.; Moise, E.
2007ApJ...667L.203K Altcode:
Sensitive spectropolarimetric observations from the Haleakala SOLARC
coronagraph and infrared imaging spectropolarimeter have detected an
extended diffuse surface brightness flux at the 1083 nm wavelength
of neutral helium (He I). This has the polarization signature of
light scattered by an extended He I cloud in the vicinity of the
Sun. The He I scattered surface brightness appears to be consistent
with a previous eclipse measurement and satellite observations of the
local interstellar medium (LISM) helium wind (LISW), obtained using
observations of the He I UV resonance line at 58.4 nm. The sensitivity
of the infrared coronagraphic method suggests that the LISW interaction
with the local solar wind can have observable consequences that may
yield a useful ground-based technique for studying the coronal and
interplanetary plasma.
---------------------------------------------------------
Title: A New Mechanism for Polarizing Light from Obscured Stars
Authors: Kuhn, J. R.; Berdyugina, S. V.; Fluri, D. M.; Harrington,
D. M.; Stenflo, J. O.
2007ApJ...668L..63K Altcode: 2007arXiv0708.0599K
Recent spectropolarimetric observations of Herbig Ae/Be stellar systems
show linear polarization variability with wavelength and epoch near
their obscured Hα emission. Surprisingly, this polarization is
not coincident with the Hα emission peak but is variable near the
absorptive part of the line profile. With a new and novel model, we
show here that this is evidence of optical pumping-anisotropy of the
incident radiation that leads to a linear polarization-dependent optical
depth within the intervening hydrogen wind or disk cloud. This effect
can yield a larger polarization signal than scattering polarization
in these systems.
---------------------------------------------------------
Title: Spectropolarimetry of the Hα Line in Herbig Ae/Be Stars
Authors: Harrington, D. M.; Kuhn, J. R.
2007ApJ...667L..89H Altcode: 2007arXiv0708.0601H
Using the HiVIS spectropolarimeter built for the Haleakala 3.7 m
AEOS telescope, we have obtained a large number of high-precision
spectropolarimetrc observations (284) of Herbig AeBe stars collected
over 53 nights totaling more than 300 hr of observing. Our sample of
five HAeBe stars, AB Aurigae, MWC 480, MWC 120, MWC 158, and HD 58647,
all show systematic variations in the linear polarization amplitude and
direction as a function of time and wavelength near the Hα line. In
all our stars, the Hα line profiles show evidence of an intervening
disk or outflowing wind, evidenced by strong emission with an absorptive
component. The linear polarization varies by 0.2%-1.5% with the change
typically centered in the absorptive part of the line profile. These
observations are inconsistent with a simple disk-scattering model or
a depolarization model that produce polarization changes centered on
the emissive core. We speculate that polarized absorption via optical
pumping of the intervening gas may be the cause.
---------------------------------------------------------
Title: The Lyot Project: Status and Results
Authors: Sivaramakrishnan, A.; Oppenheimer, B. R.; Soummer, R.;
Hinkley, S.; Brenner, D.; Leconte, J.; Roberts, L. C.; Perrin, M. D.;
Lloyd, J. P.; Makidon, R. B.; Kuhn, J. R.
2007lyot.confE..21S Altcode:
The Lyot Project near-IR coronagraph, operating behind the AEOS 3.6m
941-channel adaptive optics system, has opened up new search areas
in the mass-separation parameter space of faint companions to nearby
stars brighter than V=7. As the first so-called extreme AO system
on sky, often operating at a 90% Strehl ratio at H with an upgraded
AEOS AO system, its use has uncovered some hitherto unforeeseen
difficulties in the search for faint companions. The coronagraph
possesses a simultaneous dual-polarization mode and a novel technique
for precision relative astrometry and photometry. We have also developed
a refinement of the angular differential imaging technique in order to
suppress the static and quasi-static speckles that limit our dynamic
range. We are about to explore newer coronagraph designs, and place
an Integral Field Unit spectrograph behind the coronagraph.
---------------------------------------------------------
Title: The Lyot Project: Survey Analysis
Authors: Leconte, J.; Soummer, R.; Oppenheimer, B. R.; Hinkley, S.;
Brenner, D.; Sivaramakrishnan, A.; Kuhn, J.; Perrin, M. D.; Roberts,
L. C., Jr.; Simon, M.; Brown, R. A.; Chabrier, G.; Baraffe, I.
2007lyot.confE..44L Altcode:
The Lyot project survey has observed 57 stars so far. We have developed
some image processing and analysis tools to reduce speckle noise with
Angular Differential Imaging, and to estimate the detection sensitivity
(dynamic range) from the data. We apply these techniques to each
star of the survey, and give a general overview of the instrument
sensitivity. We use a Monte-Carlo based approach to define the possible
population of companions around these stars, and we determine the
completeness of each observation as a function of mass and semi-major
axis, according to the measured dynamic range for each star. We use
the overall survey non-detection results to constrain the possible
population of companions.
---------------------------------------------------------
Title: Mees Imaging Solar Spectrometer
Authors: Lin, Haosheng; Li, J.; Kuhn, J. R.; Mickey, D.; Habbal,
S. R.; Jaeggli, S. S.
2007AAS...210.9215L Altcode: 2007BAAS...39R.210L
We propose the construction of a new instrument, the Mees Imaging Solar
Spectrometer (MISS), optimized for spectroscopic study of energetic
solar events such as filament eruptions and solar flares, and their
relationship to coronal mass ejections. MISS is a fiber-optics-based
imaging spectrograph. It will be able to perform simultaneous
spectroscopic observations of selected spectral lines and continuum
over an extended field with high spatial and spectral resolution
and high cadence. It will operate nominally in a low-resolution (20"
per pixel), full-disk patrol mode, and can be rapidly switched to a
high-resolution (1" per pixel) region-of-interest mode of observation
when energetic events are detected. Several spectral lines, from CaII
H & K to HeI 1083 nm can be recorded in rapid succession. These
advanced imaging spectroscopic capabilities make it an ideal instrument
for the study of the rapid change of the physical conditions of the
solar atmosphere during these energetic events.
---------------------------------------------------------
Title: Observing Interstellar Neutral Helium from the Ground
Authors: Moise, Elena; Kuhn, J.
2007AAS...21012007M Altcode: 2007BAAS...39..246M
Cool neutral Helium is now being observed near the Sun. Routine
observations by SOLARC at Haleakala Observatory (by means of IR
spectropolarimetry) reveal the existence of scattered photospheric
light at 1083nm from HeI far above the solar limb. Here we report on
recent observations of this transient coronal constituent that help us
understand whether this cool HeI comes from the coronal "inner source"
or from the interstellar Helium wind.
---------------------------------------------------------
Title: A Changing Solar Shape
Authors: Kuhn, Jeffrey R.; Emilio, M.; Bush, R.; Scherrer, P.
2007AAS...21012001K Altcode: 2007BAAS...39..245K
The Sun's shape is sensitive to the influence of gravity, rotation, and
local turbulence and magnetic fields in its outer atmosphere. In 1997
the Michelson Doppler Imager (MDI) aboard the Solar and Heliospheric
Observatory (SOHO) allowed a precise measurement of the oblateness from
above the atmosphere. In 2001 this technique was repeated and we report
here on the detection of a time-variable solar shape from these data.
---------------------------------------------------------
Title: What Makes The Advanced Technology Solar Telescope (ATST)
So Advanced?
Authors: Kuhn, Jeffrey R.; Rimmele, T.; ATST Design Team
2007AAS...210.6701K Altcode: 2007BAAS...39..175K
-- Its the science! While its true that we haven't advanced ground-based
solar astronomy by a leap as big as this since Galileo, its the
qualitatively new insights that we expect with ATST that drive its
design. ATST isn't so much a telescope as much as it is a sensitive
magnetometer, and a high dynamic range imaging spectropolarimeter. In
this talk we'll try to draw the lines between the questions you've
always wanted to ask about the Sun, and this unique optical and
infrared instrument.
---------------------------------------------------------
Title: Molecular Hydrogen Dynamics in the Cool Photosphere
Authors: Downs, Cooper; Kuhn, J.
2007AAS...210.2501D Altcode: 2007BAAS...39..131D
Molecular hydrogen can be a major component of the cool solar
photosphere in magnetic regions. The steep dependence in the abundance
fraction of the molecular species with temperature can produce strong
relative density gradients that can dominate the local hydrostatic
pressure. These pressure gradients can produce "diffusive" shock
fronts that may have important dynamical consequences on, for example,
sunspot penumbrae formation. We explore some simple analytic and
numerical multi-fluid models that illustrate these dynamical effects.
---------------------------------------------------------
Title: A Changing Solar Shape
Authors: Emilio, M.; Bush, R. I.; Kuhn, J.; Scherrer, P.
2007ApJ...660L.161E Altcode:
The Sun's shape is sensitive to the influence of gravity, rotation,
and local turbulence and magnetic fields in its outer atmosphere. A
careful measurement of this shape has long been sought to better
understand the solar structure and its change during the 11 yr solar
cycle. Numerous disparate measurements of the solar oblateness or
the fractional difference between equatorial and polar radii have
been difficult to interpret, in part because this quantity is much
smaller than terrestrial atmospheric seeing and most instrumental
noise sources. In 1997 the Michelson Doppler Imager (MDI) aboard
the Solar and Heliospheric Observatory (SOHO) obtained a precise
measurement of the oblateness from above the atmosphere by utilizing
a spacecraft roll procedure to remove instrumental influences. In 2001
this technique was repeated, and we report here on the detection of a
time-variable solar shape from these data. The changing oblateness we
find from 1997 to 2001 is smaller than the apparent discrepancy between
earlier ground-based observations, but is significantly larger than
MDI's astrometric measurement uncertainty. The shape change appears
to be anticorrelated with the observed helioseismic variability. This
fact and our MDI measurements suggest that the outer solar atmosphere
expands nonhomologously during the cycle. It is possible that solar
cycle changes in the turbulent pressure in the outer atmosphere can
account for both the optical limb change and the helioseismic acoustic
global solar shape change.
---------------------------------------------------------
Title: The Lyot Project: status and results
Authors: Sivaramakrishnan, Anand; Oppenheimer, Ben R.; Hinkley, Sasha;
Brenner, Douglas; Soummer, Rémi; Mey, Jacob L.; Lloyd, James P.;
Perrin, Marshall D.; Graham, James R.; Makidon, Russell B.; Roberts,
Lewis C.; Kuhn, Jeffrey R.
2007CRPhy...8..355S Altcode:
We present a retrospective on, and some new imaging data from The
Lyot Project JHK coronagraph which is used behind the 3.6 m AEOS
941-channel AO telescope on Mt. Haleakala, on the island of Maui in
Hawaii. This instrument is the first ‘extreme adaptive optics’
(ExAO) coronagraph ever; it opens up new scientific search spaces in
direct imaging of faint companions of nearby stars. It also blazed
a trail for current ExAO systems being developed for ESO-VLT and
Gemini telescopes. Amongst other things, the Lyot Project has been
used to demonstrate a device for precision coronagraphic astrometry
and photometry using the novel technique of placing a wire grid
over the pupil to create stable fiducial ghost images, to show the
effects of frozen actuators on a deformable mirror, to refine angular
differential imaging for use on the Coudé focus of Alt-Az telescopes,
and to develop a coronagraphic data reduction pipeline. To cite this
article: A. Sivaramakrishnan et al., C. R. Physique 8 (2007).
---------------------------------------------------------
Title: Spectropolarimetry of the Deep Impact target Comet 9P/Tempel
1 with HiVIS
Authors: Harrington, D. M.; Meech, K.; Kolokolova, L.; Kuhn, J. R.;
Whitman, K.
2007Icar..187..177H Altcode:
High resolution spectropolarimetry of the Deep Impact target, Comet
9P/Tempel 1, was performed during the impact event on July 4th, 2005
with the HiVIS spectropolarimeter and the AEOS 3.67-m telescope on
Haleakala, Maui. We observed atypical polarization spectra that changed
significantly in the few hours after the impact. The polarization of
scattered light as a function of wavelength is very sensitive to the
size and composition (complex refractive index) of the scattering
particles as well as the scattering geometry. As opposed to most
observations of cometary dust, which show an increase in the linear
polarization with the wavelength (at least in the visible domain and
for phase angles greater than about 30, a red polarization spectrum)
observations of 9P/Tempel 1 at a phase angle of 41° beginning 8 min
after impact and centered at 6:30 UT showed a polarization of 4% at 650
nm falling to 3% at 950 nm. The next observation, centered an hour later
showed a polarization of 7% at 650 nm falling to 2% at 950 nm. This
corresponds to a spectropolarimetric gradient, or slope, of -0.9% per
1000 Å 40 min after impact, decreasing to a slope of -2.3% per 1000 Å
an hour and a half after impact. This is an atypical blue polarization
slope, which became more blue 1 h after impact. The polarization values
of 4 and 7% at 650 nm are typical for comets at this scattering angle,
whereas the low polarization of 2 and 3% at 950 nm is not. We compare
observations of Comet 9P/Tempel 1 to that of a typical comet, C/2004
Machholz, at a phase angle of 30° which showed a typical red slope,
rising from 2% at 650 nm to 3% at 950 nm in two different observations
(+1.0 and +0.9% per 1000 Å).
---------------------------------------------------------
Title: Temporal Evolution of Coronagraphic Dynamic Range and
Constraints on Companions to Vega
Authors: Hinkley, Sasha; Oppenheimer, Ben R.; Soummer, Rémi;
Sivaramakrishnan, Anand; Roberts, Lewis C., Jr.; Kuhn, Jeffrey;
Makidon, Russell B.; Perrin, Marshall D.; Lloyd, James P.; Kratter,
Kaitlin; Brenner, Douglas
2007ApJ...654..633H Altcode: 2006astro.ph..9337H
The major obstacle to the direct detection of companions to nearby
stars is the overwhelming brightness of the host star. Current
instruments employing the combination of adaptive optics (AO) and
coronagraphy can typically detect objects within 2" of the star that are
~10<SUP>4</SUP>-10<SUP>5</SUP> times fainter. Correlated speckle noise
is one of the biggest obstacles limiting such high-contrast imaging. We
have obtained a series of 284 8 s, AO-corrected, coronagraphically
occulted H-band images of the star Vega at the 3.63 m AEOS telescope
located on Haleakala, Hawaii. This data set is unique for studying the
temporal behavior of speckle noise and represents the first time such a
study on highly corrected coronagraphic AO images has been carried out
in a quantitative way. We find the speckle pattern to be highly stable
in both position and time in our data. This is due to the fact that the
AO system corrects disturbances to the stellar wave front at the level
where the instrumental wave front errors dominate. Because of this,
we find that our detection limit is not significantly improved simply
with increased exposure time alone. However, we are able to improve our
dynamic range by 1.5-2 mag through subtraction of static/quasi-static
speckles in two rotating frames: the telescope pupil frame and the
deformable mirror frame. The highly stable nature of speckles will exist
for any program using coronagraphy and high-order AO. Furthermore,
from our data, we are able to constrain the mass of any purported
companion to Vega to be less than ~45M<SUB>J</SUB> at 8 AU and less
than ~30M<SUB>J</SUB> at 16 AU, radii not previously probed at these
sensitivities.
---------------------------------------------------------
Title: Spectropolarimetry of the Deep Impact target Comet 9P/Tempel
1 with HiVIS
Authors: Harrington, D. M.; Meech, K.; Kolokolova, L.; Kuhn, J. R.;
Whitman, K.
2007Icar..191S.381H Altcode: 2007Icar..191..381H; 2006astro.ph..8676H
High resolution spectropolarimetry of the Deep Impact target, Comet
9P/Tempel 1, was performed during the impact event on July 4th, 2005
with the HiVIS spectropolarimeter and the AEOS 3.67-m telescope on
Haleakala, Maui. We observed atypical polarization spectra that changed
significantly in the few hours after the impact. The polarization of
scattered light as a function of wavelength is very sensitive to the
size and composition (complex refractive index) of the scattering
particles as well as the scattering geometry. As opposed to most
observations of cometary dust, which show an increase in the linear
polarization with the wavelength (at least in the visible domain and
for phase angles greater than about 30, a red polarization spectrum)
observations of 9P/Tempel 1 at a phase angle of 41° beginning 8 min
after impact and centered at 6:30 UT showed a polarization of 4% at 650
nm falling to 3% at 950 nm. The next observation, centered an hour later
showed a polarization of 7% at 650 nm falling to 2% at 950 nm. This
corresponds to a spectropolarimetric gradient, or slope, of -0.9% per
1000 Å 40 min after impact, decreasing to a slope of -2.3% per 1000 Å
an hour and a half after impact. This is an atypical blue polarization
slope, which became more blue 1 h after impact. The polarization values
of 4 and 7% at 650 nm are typical for comets at this scattering angle,
whereas the low polarization of 2 and 3% at 950 nm is not. We compare
observations of Comet 9P/Tempel 1 to that of a typical comet, C/2004
Machholz, at a phase angle of 30° which showed a typical red slope,
rising from 2% at 650 nm to 3% at 950 nm in two different observations
(+1.0 and +0.9% per 1000 Å).
---------------------------------------------------------
Title: Broadband Spectroscopy of the Corona during the Total Solar
Eclipse of March 29, 2006
Authors: Jaeggli, Sarah A.; Habbal, S. R.; Kuhn, J. R.; Nayfeh, M. H.
2006AAS...209.1601J Altcode: 2006BAAS...38..918J
We present coronal observations from the total solar eclipse of 29
March 2006 taken near Waw al Namus, Libya. During the 4 minutes and 6
seconds of totality, observations were made with a tracking collecting
mirror and fiber-fed spectrograph. The spectrograph used is a high
quantum efficiency commercial Ocean Optics QE65000 Spectrometer with a
wavelength range of 350 to 1100 nm, and spectral resolution of about
0.75 nm. High quantum efficiency allowed for many short exposures
of the inner (100 msec) and outer (10,000 msec) corona during the
eclipse. Important spectral features, and the difference in color
between the inner and outer corona are identified. Atmospheric
contributions are discussed. Likely candidates for the nature of
dust grains contributing to the F-corona measurements are also
presented. These are compared with laboratory spectra of silicon
nanoparticles.
---------------------------------------------------------
Title: Osmotically Driven Neutral Sunspot Winds
Authors: Kuhn, J. R.; Morgan, H.
2006ASPC..354..230K Altcode:
The low ionization state in parts of a sunspot may play an important
role in its evolution and dynamical state. The cool magnetic interior
region of the umbra develops a substantial neutral atomic and molecular
hydrogen osmotic pressure which can drive a wind outward from the
umbra. Ambipolar diffusion against the magnetically pinned ionized
plasma component can also distort the umbral magnetic field into
a filamentary penumbral structure. This wind can contribute to the
development of the sunspot penumbra and the Evershed flow.
---------------------------------------------------------
Title: Polarimetric Imaging and Spectroscopy of the Corona from 400
to 2000 nm during the Total Solar Eclipse of 29 March 2006
Authors: Habbal, S. R.; Kuhn, J.; Mickey, D.; Morgan, H.; Jaeggli,
S.; Johnson, J.; Daw, A.; Arndt, M. B.; Nayfeh, M.; Roussev, I.
2006AGUFMSH44A..06H Altcode:
Total solar eclipses continue to offer unique opportunities for
exploring the solar corona, in particular for validating new concepts,
and testing new instrumentation. We report on the results of the
observations taken during the total solar eclipse of 29 March 2006. The
eclipse was observed from Waw AnNamous, Libya, under perfect seeing
conditions. A complement of imaging and spectroscopic polarization
measurements, covering the wavelength range from 400 to 2000 nm, were
used. Among the highlights of the observations were the unexpected
radial extent of the emission from the Fe XI 789.2 nm spectral line,
which has proven to have significant potential for future coronagraphic
measurements, and the appearance of presently unidentified spectral
lines in the visible and near infrared part of the spectrum. The
implications of these results for the coronal magnetic field, and the
near-Sun dust environment will be discussed.
---------------------------------------------------------
Title: The Coronal Solar Magnetic Observatory (COSMO)
Authors: Tomczyk, S.; Zurbuchen, T.; Kuhn, J.; Lin, H.; Judge, P.;
Burkepile, J.; Casini, R.
2006AGUFMSM12A..03T Altcode:
Measurement of magnetic fields in the corona is arguably the most
important observable required for advances in our understanding of
the emergence of magnetic flux into the solar atmosphere and the
processes responsible for the production of solar activity, coronal
heating and coronal dynamics. We discuss plans for the COronal Solar
Magnetic Observatory (COSMO), which is a proposed ground-based suite
of instruments designed to routinely study coronal magnetic fields and
their environment. The core of the facility includes a meter-class
coronagraph with instrumentation dedicated to measuring the coronal
magnetic field using the polarization of forbidden emission lines in
the infrared. Supporting instruments focus on prominence magnetometry
and the dynamics of the electron-scattered corona (K-corona) and
chromosphere. In addition to acquiring routine synoptic observations
of coronal magnetic fields, the COSMO project will include the
establishment of a community-based user advisory panel to accept
observational campaigns submitted by members of the scientific community
at-large. COSMO will enhance the value of existing and new observatories
on the ground (SOLIS, ATST, FASR) and in space (SOHO, TRACE, GOES,
Solar-B, STEREO and SDO) by providing unique and crucial observations
of the global coronal magnetic field and its evolution and dynamics.
---------------------------------------------------------
Title: The Challenges of Coronagraphic Astrometry
Authors: Digby, Andrew P.; Hinkley, Sasha; Oppenheimer, Ben R.;
Sivaramakrishnan, Anand; Lloyd, James P.; Perrin, Marshall D.;
Roberts, Lewis C., Jr.; Soummer, Rémi; Brenner, Douglas; Makidon,
Russell B.; Shara, Michael; Kuhn, Jeffrey; Graham, James; Kalas,
Paul; Newburgh, Laura
2006ApJ...650..484D Altcode:
A coronagraph in conjunction with adaptive optics provides an effective
means to image faint companions of nearby stars from the ground. The
images from such a system are complex, however, and need to be fully
characterized and understood before planets or disks can be detected
against the glare from the host star. Using data from the Lyot Project
coronagraph, we investigate the difficulties of astrometric measurements
in diffraction-limited coronagraphic images and consider the principal
problem of determining the precise location of the occulted star. We
demonstrate how the image structure varies when the star is decentered
from the optical axis and show how even small offsets (0.05λ/D or 5
mas) give rise to false sources in the image. We consider methods of
determining the star position from centroiding, instrument feedback, and
analysis of point-spread function symmetry and conclude that internal
metrology is the most effective technique. <P />Based on observations
made at the Maui Space Surveillance System operated by Detachment 15
of the US Air Force Research Laboratory's Directed Energy Directorate.
---------------------------------------------------------
Title: Progress on the 1.6-meter New Solar Telescope at Big Bear
Solar Observatory
Authors: Denker, C.; Goode, P. R.; Ren, D.; Saadeghvaziri, M. A.;
Verdoni, A. P.; Wang, H.; Yang, G.; Abramenko, V.; Cao, W.; Coulter,
R.; Fear, R.; Nenow, J.; Shoumko, S.; Spirock, T. J.; Varsik, J. R.;
Chae, J.; Kuhn, J. R.; Moon, Y.; Park, Y. D.; Tritschler, A.
2006SPIE.6267E..0AD Altcode: 2006SPIE.6267E..10D
The New Solar Telescope (NST) project at Big Bear Solar Observatory
(BBSO) now has all major contracts for design and fabrication in place
and construction of components is well underway. NST is a collaboration
between BBSO, the Korean Astronomical Observatory (KAO) and Institute
for Astronomy (IfA) at the University of Hawaii. The project will
install a 1.6-meter, off-axis telescope at BBSO, replacing a number
of older solar telescopes. The NST will be located in a recently
refurbished dome on the BBSO causeway, which projects 300 meters into
the Big Bear Lake. Recent site surveys have confirmed that BBSO is
one of the premier solar observing sites in the world. NST will be
uniquely equipped to take advantage of the long periods of excellent
seeing common at the lake site. An up-to-date progress report will
be presented including an overview of the project and details on the
current state of the design. The report provides a detailed description
of the optical design, the thermal control of the new dome, the optical
support structure, the telescope control systems, active and adaptive
optics systems, and the post-focus instrumentation for high-resolution
spectro-polarimetry.
---------------------------------------------------------
Title: The New HiVIS Spectropolarimeter and Spectropolarimetric
Calibration of the AEOS Telescope
Authors: Harrington, D. M.; Kuhn, J. R.; Whitman, K.
2006PASP..118..845H Altcode: 2006astro.ph..6503H
We have designed, built, and calibrated a new spectropolarimeter
for the HiVIS spectrograph (R ~ 12,000-49,000) on the Advanced
Electro-Optical System (AEOS) telescope. We have also conducted a
polarization calibration of the telescope and instrument. In this paper,
we introduce the design and use of the spectropolarimeter, in addition
to a new data-reduction package we have developed, and then discuss
the polarization calibration of the spectropolarimeter and the AEOS
telescope. We used observations of unpolarized standard stars at many
pointings to measure the telescope-induced polarization and compare
it with a Zemax model. The telescope induces polarization of 1%-6%,
with a strong variation with wavelength and pointing, consistent with
the expected altitude and azimuth variation. We then used scattered
sunlight as a linearly polarized source to measure the telescope's
spectropolarimetric response to linearly polarized light. Finally,
we made an all-sky map of the telescope's polarization response to
calibrate future spectropolarimetry.
---------------------------------------------------------
Title: Site testing for the Advanced Technology Solar Telescope
Authors: Hill, F.; Beckers, J.; Brandt, P.; Briggs, J.; Brown, T.;
Brown, W.; Collados, M.; Denker, C.; Fletcher, S.; Hegwer, S.; Horst,
T.; Komsa, M.; Kuhn, J.; Lecinski, A.; Lin, H.; Oncley, S.; Penn,
M.; Radick, R.; Rimmele, T.; Socas-Navarro, H.; Streander, K.
2006SPIE.6267E..1TH Altcode: 2006SPIE.6267E..59H
The Advanced Solar Technology Telescope (ATST) is a 4-m solar telescope
being designed for high spatial, spectral and temporal resolution,
as well as IR and low-scattered light observations. The overall
limit of performance of the telescope is strongly influenced by the
qualities of the site at which it is located. Six sites were tested
with a seeing monitor and a sky brightness instrument for 1.5 to 2
years. The sites were Big Bear (California), Haleakala (Hawaii), La
Palma (Canary Islands, Spain), Panguitch Lake (Utah), Sacramento Peak
(New Mexico), and San Pedro Martir (Baja California, Mexico). In this
paper we will describe the methods and results of the site survey,
which chose Haleakala as the location of the ATST.
---------------------------------------------------------
Title: Using Polarimetric Imaging and Spectroscopy of the Corona
from 400 to 1800 nm for Exploring the near Sun Plasma
Authors: Habbal, S. Rifai; Kuhn, J.; Mickey, D.; Jaeggli, S.; Morgan,
H.; Roussev, I.; Johnson, J.; Arndt, M. B.; Daw, A.; Nayfeh, M. H.
2006spse.conf...27H Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Infrared Coronal Polarimetry: Magnetometry and More
Authors: Kuhn, J.; Lin, H.; Jaeggli, S.; Arnaud, J.; Mickey, D.
2006cosp...36.1643K Altcode: 2006cosp.meet.1643K
Near-infrared spectropolarimetry of the solar corona is a powerful tool
for measuring the coronal magnetic field and even the local interstellar
wind Here we describe how sensitive imaging spectropolarimetric
observations are being obtained from the worlds largest coronagraph --
a reflecting off-axis telescope -- from the summit of Haleakala Hawai i
---------------------------------------------------------
Title: The Lyot project coronagraph: data processing and performance
analysis
Authors: Soummer, R.; Oppenheimer, B. R.; Hinkley, S.;
Sivaramakrishnan, A.; Makidon, R. B.; Digby, A.; Brenner, D.; Kuhn,
J.; Perrin, M. D.; Roberts, L. C., Jr.; Kratter, K.
2006EAS....22..199S Altcode:
In this communication we illustrate the main steps required for the
preprocessing of the Lyot Project Coronagraph data, starting from the
raw data to the reduced data. We then discuss the estimation of the
performance on direct, unocculted data, by measuring the Strehl Ratio
on these images. We show that Strehl Ratios of the order of 80% can be
obtained for the best images in the H Band, using the AEOS telescope
adaptive optics, and the Kermit infrared camera. We then present a
few methods to estimate the dynamic range in coronagraphic images,
and their results are discussed.
---------------------------------------------------------
Title: Scattered Light Suppression and IR Polarimetry
Authors: Kuhn, J. R.
2005ASPC..343...22K Altcode:
Dual-beam polarimetry is an effective tool for high dynamic range
imaging of circumstellar regions. We have achieved scattered light
suppression exceeding 5 magnitudes over angular scales where current
adaptive optics systems are not useful. This paper describes some
techniques and algorithms that are generally helpful for detecting
faint circumstallar scattered light associated with disk systems.
---------------------------------------------------------
Title: Using Imaging Infrared Coronal Spectropolarimetry to Measure
the Near-Sun Plasma
Authors: Kuhn, J.; Lin, H.; Arnaud, J.; Jaeggli, S.
2005AGUFMSH44A..08K Altcode:
A moderate aperture ground-based coronagraph and an imaging infrared
spectropolarimeter have provided our first direct longitudinal coronal
magnetograms. This talk will describe the advantages and subtleties of
these techniques for direct coronal magnetometry. We also summarize
some of the diagnostic potential of current and likely future IR
spectropolarimetric instruments (like the Advanced Technology Solar
Telescope) for measuring the properties of the near-solar plasma.
---------------------------------------------------------
Title: Solar Site Survey for the Advanced Technology Solar
Telescope. I. Analysis of the Seeing Data
Authors: Socas-Navarro, H.; Beckers, J.; Brandt, P.; Briggs, J.;
Brown, T.; Brown, W.; Collados, M.; Denker, C.; Fletcher, S.; Hegwer,
S.; Hill, F.; Horst, T.; Komsa, M.; Kuhn, J.; Lecinski, A.; Lin, H.;
Oncley, S.; Penn, M.; Rimmele, T.; Streander, K.
2005PASP..117.1296S Altcode: 2005astro.ph..8690S
The site survey for the Advanced Technology Solar Telescope concluded
recently after more than 2 years of data gathering and analysis. Six
locations, including lake, island, and continental sites, were
thoroughly probed for image quality and sky brightness. The present
paper describes the analysis methodology employed to determine the
height stratification of the atmospheric turbulence. This information
is crucial, because daytime seeing is often very different between the
actual telescope aperture (~30 m) and the ground. Two independent
inversion codes have been developed to simultaneously analyze
data from a scintillometer array and a solar differential image
monitor. We show here the results of applying them to a sample subset
of data from 2003 May that was used for testing. Both codes retrieve a
similar seeing stratification through the height range of interest. A
quantitative comparison between our analysis procedure and actual in
situ measurements confirms the validity of the inversions. The sample
data presented in this paper reveal a qualitatively different behavior
for the lake sites (dominated by high-altitude seeing) and the rest
(dominated by near-ground turbulence).
---------------------------------------------------------
Title: Exploring Halo Substructure with Giant Stars: The Velocity
Dispersion Profiles of the Ursa Minor and Draco Dwarf Spheroidal
Galaxies at Large Angular Separations
Authors: Muñoz, Ricardo R.; Frinchaboy, Peter M.; Majewski, Steven R.;
Kuhn, Jeffrey R.; Chou, Mei-Yin; Palma, Christopher; Sohn, Sangmo Tony;
Patterson, Richard J.; Siegel, Michael H.
2005ApJ...631L.137M Altcode: 2005astro.ph..4035M
We analyze velocity dispersion profiles for the Draco and Ursa Minor
(UMi) dwarf spheroidal (dSph) galaxies based on published and new Keck
HIRES spectra for stars in the outer UMi field. Washington + DDO51
filter photometric catalogs provide additional leverage on membership of
individual stars and, beyond 0.5 King limiting radii (r<SUB>lim</SUB>),
identify bona fide dSph members up to 4.5 times more efficiently than
simple color-magnitude diagram selections. Previously reported “cold
populations” at r<SUB>lim</SUB> are not obvious in the data and appear
only with particular binning; more or less constant and platykurtic
dispersion profiles are characteristic of these dSphs to large radii. We
report the discovery of UMi stars to at least 2.7r<SUB>lim</SUB>
(i.e., 210' or 4 kpc). Even with conservative assumptions, a UMi mass
of M>4.9×10<SUP>8</SUP> M<SUB>solar</SUB> is required to bind these
stars, implying an unlikely global mass-to-light ratio of M/L>900
(M/L)<SUB>solar</SUB>. We conclude that we have found stars tidally
stripped from UMi.
---------------------------------------------------------
Title: Are Neutral Sunspot Winds Important for Penumbral Dynamics
and the First Ionization Potential Effect?
Authors: Kuhn, J. R.; Lin, H.; Morgan, H.
2005astro.ph..9862K Altcode:
The low ionization state in parts of a sunspot may play an important
role in its evolution and dynamical state. The cool magnetic interior
region of the sunspot develops a substantial neutral atomic and
molecular hydrogen osmotic pressure which can drive a wind outward from
the umbra. Ambipolar diffusion against the magnetically pinned ionized
plasma component can also distort the umbral magnetic field into a
filamentary penumbral structure. This may be important for explaining
the development of the sunspot penumbra and the Evershed flow. This
fractionation process may also be important for the “First Ionization
Potential” (FIP) effect seen in the solar wind. In support of this
mechanism we find evidence for such ionization fractionization in UV
observations of molecular hydrogen in a sunspot umbra and penumbra.
---------------------------------------------------------
Title: High precision polarimetry with the Advanced Technology
Solar Telescope
Authors: Socas-Navarro, Hector; Elmore, David F.; Keller, Christoph
U.; Seagraves, Paul H.; Streander, Kim V.; Card, Gregory L.; Warner,
Mark; Kuhn, Jeffrey R.; Mickey, Donald L.
2005SPIE.5901...52S Altcode:
This paper addresses the issue of calibrating the Advanced Technology
Solar Telescope for high-precision polarimetry, in particular of the
optical train above the Gregorian station (where suitable calibration
optics will be placed). Conventional techniques would not be adequate
for this telescope given its large aperture. Here we explore two
different methods that are currently being considered by the design
team. The first one is the "sub-aperture" method, which uses small
calibration optics above the primary mirror to calibrate a small
sub-aperture of the system. This calibration is then extended to the
full aperture by means of actual observations. The second method is
based on analyzing the polarization observed in a spectral line with
a peculiar Zeeman pattern, such as the FeII 614.9 nm line, which does
not produce any intrinsic linear polarization. Numerical simulations
are presented that show the robustness of both techniques and their
respective advantages and disadvantages are discussed.
---------------------------------------------------------
Title: Spectropolarimetry of the dust coma of Deep Impact target
9P/Tempel 1
Authors: Harrington, D. M.; Meech, K. J.; Kuhn, J.; Kolokolova, L.;
Pittichova, J.; Harrington, D. M.; Meech, K. J.; Kuhn, J.; Kolokolova,
L.; Pittichova, J.
2005DPS....37.4402H Altcode: 2005BAAS...37Q.715H
Spectropolarimetry can be used to measure polarization of cometary
continua as a function of wavelength and phase angle to learn about
the dust properties. The wavelength dependence of the polarization
is mainly controlled by the complex refractive index of the material
making up the particles, and the spectral dependence of the intensity
is also sensitive to the size of the particles. We will use the new
IfA-designed high-resolution spectropolarimeter (R 12000 to 49000,
from 5400 to 9900 Angstroms) mounted on the AEOS 3.7m telescope on
Haleakala, Maui to characterize the size and composition of dust grains
ejected from the comets. We will combine optical measurements of dust
comae, Finson-Probstein dust-dynamical models (to get particle size
distributions), and polarization spectra to study the composition of the
dust grains in comet 9P/Tempel 1 both pre- and post impact to look for
dust compositional changes between the pristine interior materials and
the surface dust on the nucleus. <P />Support for this work was provided
through University of Maryland and University of Hawaii subcontract
Z667702, which was awarded under prime contract NASW-00004 from NASA.
---------------------------------------------------------
Title: Radial Alignment of Cluster Galaxies
Authors: Pereira, M. J.; Kuhn, J. R.
2005ApJ...627L..21P Altcode: 2004astro.ph.11710P
We report the discovery of a statistically significant radial alignment
of cluster galaxies in a sample of 85 X-ray-selected clusters observed
in the Sloan Digital Sky Survey. The tendency for alignment is a
robust feature of our sample and does not vary significantly with
individual cluster or galaxy properties. We use dynamical arguments
to show that a significant fraction of cluster galaxies should be
undergoing a parametric tidal resonance that can cause their long axes
to orient themselves toward the center of the cluster potential, and
therefore tentatively ascribe the observed radial alignment to this
dynamical effect.
---------------------------------------------------------
Title: The ATST Site Survey
Authors: Hill, F.; Beckers, J.; Brandt, P.; Briggs, J. W.; Brown, T.;
Brown, W.; Collados, M.; Denker, C.; Fletcher, S.; Hegwer, S.; Horst,
T.; Komsa, M.; Kuhn, J.; Lecinski, A.; Lin, H.; Oncley, S.; Penn, M.;
Radick, R.; Rimmele, T.; Socas-Navarro, H.; Soltau, D.; Streander, K.
2005AGUSMSP34A..04H Altcode:
The Advanced Technology Solar Telescope (ATST) will be the world's
largest aperture solar telescope, and is being designed for high
resolution, IR, and coronal research. It must be located at a site that
maximizes the scientific return of this substantial investment. We
present the instrumentation, analysis and results of the ATST site
survey. Two instrumentation sets were deployed at each of six sites to
measure seeing as a function of height, and sky brightness as a function
of wavelength and off-limb position. Analysis software was developed
to estimate the structure function Cn2 as a function of height near
the ground, and the results were verified by comparison with in-situ
measurements. Additional software was developed to estimate the sky
brightness. The statistics of the conditions at the sites were corrected
for observing habits and the annualized hours of specific observing
conditions were estimated. These results were used to identify three
excellent sites suitable to host the ATST: Haleakala, Big Bear and La
Palma. Among them, Haleakala is proposed as the optimal location of
the ATST, La Palma and Big Bear being viable alternative sites.
---------------------------------------------------------
Title: The New Solar Telescope at Big Bear Solar Observatory -
A Progress Report
Authors: Denker, C.; Cao, W.; Chae, J.; Coulter, R.; Kuhn, J. R.;
Marquette, W. H.; Moon, Y.; Park, Y.; Ren, D.; Tritschler, A.; Varsik,
J. R.; Wang, H.; Yang, G.; Shoumko, S.; Goode, P. R.
2005AGUSMSP43A..07D Altcode:
The New Solar Telescope (NST) is a new 1.6-meter, off-axis telescope
for the Big Bear Solar Observatory (BBSO) in California. The NST is
collaboration between BBSO, the Korean Astronomical Observatory (KAO)
and Institute for Astronomy (IfA) at the University of Hawaii. BBSO
is an ideal site for high-spatial resolution observations, since this
mountain-lake site provides consistent seeing conditions with extended
periods of excellent seeing from sunrise to sunset. These unique seeing
characteristics make BBSO ideally suited for combined high-resolution
campaigns and synoptic observations, which are essential for studies
of solar activity and space weather. In this progress report, we
present the latest information on the optical design, the optical
support structure, the telescope control system and the requisite
instrumentation for the telescope. Acknowledgements: This work has been
supported by NSF under grants ATM-0236945, ATM-0342560, MRI-0320540,
and Air Force DURIP F-49620-03-1-0271.
---------------------------------------------------------
Title: First-Light Instrumentation for the Advanced Technology
Solar Telescope
Authors: Rimmele, T.; Balasubramaniam, K.; Berger, T.; Elmore, D.;
Gary, A.; Keller, C.; Kuhn, J.; Lin, H.; Mickey, D.; Pevtsov, A.;
Robinson, B.; Sigwarth, M.; Soccas-Navarro, H.
2005AGUSMSP34A..03R Altcode:
The 4m Advanced Technology Solar Telescope (ATST) is the next
generation ground based solar telescope. In this paper we provide
an overview of the ATST post-focus instrumentation. The majority of
ATST instrumentation is located in an instrument Coude lab facility,
where a rotating platform provides image de-rotation. A high order
adaptive optics system delivers a corrected beam to the Coude lab
facility. Alternatively, instruments can be mounted at the Nasmyth
focus. For example, instruments for observing the faint corona
preferably will be mounted at Nasmyth where maximum throughput
is achieved. In addition, the Nasmyth focus has minimum telescope
polarization and minimum stray light. We give an overview of the
initial set of first generation instruments: the Visible-Light
Broadband Imager (VLBI), the Visible Spectro-Polarimeter (ViSP),
the Near-IR Spectro-Polarimeter (NIRSP), which includes a coronal
module, and the Visible Tunable Filter. We also discuss the unique and
efficient approach to the ATST instrumentation, which builds on the use
of common components such as detector systems, polarimetry packages
and various opto-mechanical components. For example, the science
requirement for polarimetric sensitivity (10-5 relative to intensity)
and accuracy (5'10-4 relative to intensity) place strong constraints
on the polarization analysis and calibration units. Consequently,
these systems are provided at the facility level, rather than making
it part of the requirement for each instrument.
---------------------------------------------------------
Title: Improving Ocean Analyses and ENSO Forecasts at NOAA Using
the Global Ocean Data Assimilation System and Altimetric Sea Level
Authors: Lillibridge, J.; Behringer, D.; Xue, Y.; Kuhn, J.
2005ESASP.572E.139L Altcode: 2005eers.sympE.139L
No abstract at ADS
---------------------------------------------------------
Title: Light-Weight Local Group Dwarf Spheroidal Galaxies
Authors: Kuhn, J. R.; Kocevski, D.; Fleck, J. -J.
2004ASPC..327..150K Altcode: 2003astro.ph..9207K
A simple and natural explanation for the dynamics and morphology
of the Local Group Dwarf Spheroidal galaxies, Draco (Dra) and Ursa
Minor (UMi), is that they are weakly unbound stellar systems with no
significant dark matter component. A gentle, but persistent, Milky Way
(MW) tide has left them in their current kinematic and morphological
state. This short paper reviews the parametric tidal interaction
model which accounts for their behavior and discusses new statistical
evidence from the observed stellar distribution in Dra which implies
that its total mass is not dominated by collisionless dark matter (DM).
---------------------------------------------------------
Title: The Lyot project: toward exoplanet imaging and spectroscopy
Authors: Oppenheimer, Ben R.; Digby, Andrew P.; Newburgh, Laura;
Brenner, Douglas; Shara, Michael; Mey, Jacob; Mandeville, Charles;
Makidon, Russell B.; Sivaramakrishnan, Anand; Soummer, Remi; Graham,
James R.; Kalas, Paul; Perrin, Marshall D.; Roberts, Lewis C., Jr.;
Kuhn, Jeffrey R.; Whitman, Kathryn; Lloyd, James P.
2004SPIE.5490..433O Altcode:
Among the adaptive optics systems available to astronomers,
the US Air Force Advanced Electro-Optical System (AEOS) is unique
because it delivers very high order wave front correction. The Lyot
Project includes the construction and installation of the world"s
first diffraction-limited, optimized coronagraph that exploits the
full astronomical potential of AEOS and represents a critical step
toward the long-term goal of directly imaging and studying extrasolar
planets (a.k.a. "exoplanets"). We provide an update on the Project,
whose coronagraph saw first light in March 2004. The coronagraph is
operating at least as well as predicted by simulations, and a survey
of nearby stars has begun.
---------------------------------------------------------
Title: On the Constancy of the Solar Diameter. II.
Authors: Kuhn, J. R.; Bush, R. I.; Emilio, M.; Scherrer, P. H.
2004ApJ...613.1241K Altcode:
The Michelson Doppler Imager instrument on board SOHO has operated for
most of a solar cycle. Here we present a careful analysis of solar
astrometric data obtained with it from above the Earth's turbulent
atmosphere. These data yield the most accurate direct constraint on
possible solar radius variations on timescales from minutes to years
and the first accurate determination of the solar radius obtained in
the absence of atmospheric seeing.
---------------------------------------------------------
Title: Coronal Magnetic Field Measurements
Authors: Lin, H.; Kuhn, J. R.; Coulter, R.
2004ApJ...613L.177L Altcode:
A long-standing solar problem has been to measure the coronal magnetic
field. We believe it determines the coronal structure and dynamics from
the upper chromosphere out into the heliospheric environment. It is only
recently that Zeeman splitting observations of infrared coronal emission
lines have been successfully used to deduce the coronal magnetic flux
density. Here we extend this technique and report first results from a
novel coronal magnetometer that uses an off-axis reflecting coronagraph
and optical fiber-bundle imaging spectropolarimeter. We determine the
line-of-sight magnetic flux density and transverse field orientation
in a two-dimensional map with a sensitivity of about 1 G with 20"
spatial resolution after 70 minutes of integration. These full-Stokes
spectropolarimetric measurements of the forbidden Fe XIII 1075 nm
coronal emission line reveal the line-of-sight coronal magnetic field
100" above an active region to have a flux density of about 4 G.
---------------------------------------------------------
Title: Evidence for Light-weight Local Group Dwarf Spheroidal Galaxies
Authors: Kuhn, J. R.; Kocevski, D.
2004IAUS..220..365K Altcode:
Local Group dwarf spheroidal (dS) galaxies are a testing ground for dark
matter dominated models of galaxy structure formation and dynamical
evolution. Using Keck HIRES kinematic data CFHT deep wide-field
photometry and a new analysis of a Mathieu equation description of
parametric tidal interactions we demonstrate that these galaxies are
unlikely to be in dynamical equilibrium. The data and models imply that
dS dynamics and morphology are controlled by multiple perigalacticon
orbit passes in mildly elliptical Milky Way orbits.
---------------------------------------------------------
Title: Latest Results from the ATST Site Survey
Authors: Hill, F.; Collados, M.; Navarro, H.; Beckers, J.; Brandt,
P.; Briggs, J.; Brown, T.; Denker, C.; Hegwer, S.; Horst, T.; Komsa,
M.; Kuhn, J.; Lin, H.; Oncley, S.; Penn, M.; Rimmele, T.; Soltau,
D.; Streander, K.
2004AAS...204.6909H Altcode: 2004BAAS...36..795H
We present the latest results and current status of the site survey
portion of the Advanced Technology Solar Telescope (ATST) project. The
ATST will provide high resolution solar data in the visible and IR. The
site is a major factor determining the performance of the telescope. The
most critical site characteristics are the statistics of daytime seeing
quality and sky clarity. These conditions are being measured by a suite
of instruments at three sites (Big Bear, Haleakala, La Palma). These
sites were chosen from a set of six that have been tested starting in
November 2001. The instrumentation includes a solar differential image
motion monitor, an array of scintillometers, a miniature coronagraph,
a dust monitor, and a weather station. The analysis of the data provides
an estimate of the seeing as a function of height near the ground. We
will present the latest results of the analysis of the survey data set.
---------------------------------------------------------
Title: On the Constancy of the Solar Diameter
Authors: Kuhn, J. R.; Bush, R.; Emilio, M.; Scherrer, P.
2004AAS...204.8801K Altcode: 2004BAAS...36..819K
The solar radius and its variation have now been measured during
most of a solar cycle from the Solar and Heliospheric Observatory,
using the Michelson Doppler Imager. These instruments provide unique
astrometric data from above the Earth's atmosphere. A new analysis
based on MDI data yields a refined measurement of the solar radius
and no evidence of secular or solar cycle size variations.
---------------------------------------------------------
Title: The New Solar Telescope at Big Bear Solar Observatory
Authors: Denker, C.; Marquette, W. H.; Varsik, J.; Wang, H.; Goode,
P. R.; Moretto, G.; Kuhn, J.; Coulter, R.
2004AAS...204.6908D Altcode: 2004BAAS...36R.795D
The New Solar Telescope (NST) at Big Bear Solar Observatory is
the replacement of the current 65 cm vacuum telescope. We present
the optical design of this novel off-axis telescope with a 1.6 m
clear aperture. The NST has been designed to exploit the excellent
seeing conditions at a lake-site observatory and provide data with a
spatial resolution close the telescope's diffraction limit from the
visible to the near-infrared (NIR) wavelength region. The post-focus
instrumentation is located in the Coudé-room, a new optical laboratory
below the observing floor, which also hosts a high-order adaptive optics
system. The main instruments are two imaging spectro-polarimeters for
visible and NIR observations and a real-time image reconstruction system
for visible-light multi-color photometry. This unique combination of
instruments will realize its full potential in the studies of active
region evolution and space weather forecasts.
---------------------------------------------------------
Title: Title Requested
Authors: Lin, H.; Kuhn, J. R.; Coulter, R.
2004AAS...204.9807L Altcode: 2004BAAS...36Q.985L
A critical problem for understanding the solar corona has been
to measure its magnetic field that we believe determines its
structure and dynamics from the upper chromosphere out into the
heliospheric environment. The direct measurement of this field has
been a longstanding problem. Only recently have Zeeman splitting
observations of infrared coronal emission lines (Lin et al. 2000) been
used to deduce the coronal magnetic flux density. We have extended
this technique and report here our first results from a novel coronal
magnetometer that uses an off-axis reflecting coronagraph (SOLARC) and
optical fiber-bundle imaging spectropolarimeter (OFIS). Our results
reveal the line-of-sight magnetic flux density with a sensitivity of
a few gauss with 20 arcsec spatial resolution and approximately 60min
temporal resolution. These full Stokes spectropolarimetric data of
the forbidden FeXIII emission line at 1075nm imply a line-of-sight
coronal magnetic field above an active region with a flux density of
9G. Although these first results from SOLARC/OFIS have relatively coarse
resolution, they have potential for solving our coronal "dark energy"
problem with infrared magnetometry. This research has been supported by
the Multidisciplinary University Research Initiative (MURI) of the DOD,
NASA, and the National Science Foundation Atmospheric Research Program.
---------------------------------------------------------
Title: Irradiance and solar cycle variability: clues in cycle phase
properties
Authors: Kuhn, J. R.
2004AdSpR..34..302K Altcode:
We see solar cycle-related variations in almost every coronal,
chromospheric, and photospheric measurement obtained over a
several-years timescale. With such an abundant observational
foundation, we should expect our physical models of the solar cycle
to be overconstrained. In fact this is not the case and the "standard
dynamo model" is not predictive. This paper describes some new thoughts
on how solar irradiance variations may provide clues to the solar
cycle regulation mechanism near the radiative-convection zone boundary.
---------------------------------------------------------
Title: Fundamentals of the Solar Interior and Atmosphere
Authors: Kuhn, Jeffrey R.; McCormack, John
2004GMS...141....3K Altcode:
The practical, and immediately useful, questions related to predicting
how terrestrial climate may change are completely dependent on the
theoretical (and perhaps more fundamental) questions about how the solar
cycle varies—what causes it, and how it changes the solar outputs
which affect the Earth. For example, we obviously don't have a chance of
accurately predicting whether the next solar cycle will be dangerously
high or low if we don't have a useful physical model for it. <P />As
we have learned from decades of solar-terrestrial research, it is
not easy to find a "useful physical" model of the solar cycle. Here
"useful" is synonymous with "predictive." Until recently we've only been
able to view the cycle using magnetic observables with retrospective
models. Interestingly, over about the last cycle, we have developed
new accurate photometric and helioseismic tools. These photometric
and acoustic observables hold the promise of finally elucidating the
solar cycle physics.
---------------------------------------------------------
Title: Solar Variability and its Effects on Climate. Geophysical
Monograph 141
Authors: Pap, Judit M.; Fox, Peter; Frohlich, Claus; Hudson, Hugh S.;
Kuhn, Jeffrey; McCormack, John; North, Gerald; Sprigg, William; Wu,
S. T.
2004GMS...141.....P Altcode:
This monograph presents a state-of-the-art description of the most
recent results on solar variability and its possible influence on the
Earth's climate and atmosphere. Our primary goal in doing so is to
review solar energy flux variations (both electromagnetic and particle)
and understand their relations to solar magnetic field changes and
global effects, their impact on different atmospheric layers, and—as
a collaboration of scientists working on solar-terrestrial physics—to
note unresolved questions on an important interdisciplinary area. <P
/>One of the highest-level questions facing science today is whether
the Earth's atmosphere and climate system changes in a way that we
can understand and predict. The Earth's climate is the result of
a complex and incompletely understood system of external inputs and
interacting parts. Climate change can occur on various time scales as a
consequence of natural variability—including solar variability—or
anthropogenic causes, or both. The Sun's variability in the form
of sunspots and related magnetic activity has been the subject of
careful study ever since the earliest telescopic observations. High
precision photometric observations of solar-type stars clearly show that
year-to-year brightness variations connected with magnetic activity
are a widespread phenomenon among such stars. As our nearest star,
the Sun is the only star where we can observe and identify a variety of
structures and processes which lead to variations in the solar energy
output, in both radiative and particle fluxes. Studying event tiny
changes in solar energy flux variations may teach us about internal
processes taking place in the Sun's convective zone and below.
---------------------------------------------------------
Title: Solar variability and climate changes
Authors: Labitzke, K.; Pap, J.; Kuhn, J. R.; Shea, M. A.
2004AdSpR..34..227L Altcode:
No abstract at ADS
---------------------------------------------------------
Title: On the constancy of the solar radius
Authors: Kuhn, J.; Bush, R.; Emilio, M.; Scherrer, P.
2004cosp...35.1918K Altcode: 2004cosp.meet.1918K
The MDI experiment aboard SOHO has operated for most of a solar
cycle. From it we have obtained the most sensitive constraints
on possible solar radius variations and changes in the solar limb
darkening function over a solar cycle timescale. Here we describe the
new measurements and their implications for our understanding of the
mechanisms of solar cycle variability.
---------------------------------------------------------
Title: Preface
Authors: Pap, Judit M.; Fox, Peter; Fröhlich, Claus; Hudson, Hugh S.;
Kuhn, Jeffrey; McCormack, John; North, Gerald; Sprigg, William; Wu,
S. T.
2004GMS...141D...7P Altcode:
This monograph presents a state-of-the-art description of the most
recent results on solar variability and its possible influence on the
Earth's climate and atmosphere. Our primary goal in doing so is to
review solar energy flux variations (both electromagnetic and particle)
and understand their relations to solar magnetic field changes and
global effects, their impact on different atmospheric layers, and—as
a collaboration of scientists working on solar-terrestrial physics—to
note unresolved questions on an important interdisciplinary area. <P
/>One of the highest-level questions facing science today is whether
the Earth's atmosphere and climate system changes in a way that we
can understand and predict. The Earth's climate is the result of
a complex and incompletely understood system of external inputs and
interacting parts. Climate change can occur on various time scales as a
consequence of natural variability—including solar variability—or
anthropogenic causes, or both. The Sun's variability in the form
of sunspots and related magnetic activity has been the subject of
careful study ever since the earliest telescopic observations. High
precision photometric observations of solar-type stars clearly show that
year-to-year brightness variations connected with magnetic activity
are a widespread phenomenon among such stars. As our nearest star,
the Sun is the only star where we can observe and identify a variety of
structures and processes which lead to variations in the solar energy
output, in both radiative and particle fluxes. Studying even tiny
changes in solar energy flux variations may teach us about internal
processes taking place in the Sun's convective zone and below.
---------------------------------------------------------
Title: Mechanisms of Solar Irradiance Variations
Authors: Kuhn, J. R.; Armstrong, J. D.
2004GMS...141...87K Altcode:
This section discusses how measurements of the Sun's surface brightness
may be used to determine its total emergent flux. We explore how
solar luminosity and irradiance changes are related but distinct
phenomena, which are not well treated in one-dimensional or diffusive
solar convection zone models. Efforts to improve our knowledge of
the solar luminosity are essential, since a refined understanding
of the variability of the total solar luminosity, or even of the
net emergent energy flux from isolated parts of the photosphere are
critical tools for understanding the physics of the convection zone
and for probing deeper into the solar interior. In combination with
magnetic, helioseismic, and numerical simulation observations and tools,
the global solar luminosity and irradiance variability can reveal much
about the mechanisms of the solar cycle.
---------------------------------------------------------
Title: The HAWAII-2 2048×2048 HgCdTe Detector Arrays
Authors: Hodapp, K. W.; Kuhn, J.; Thornton, R.; Irwin, E.; Yamada,
H.; Waterson, M.; Kozlowski, L.; Montroy, J. T.; Haas, A.; Vural,
K.; Cabelli, C.
2004ASSL..300..501H Altcode: 2004sdab.conf..501H
This paper discusses the design and testing of the new HAWAII-2
devices. The HAWAII-2 design is largely based on the very successful
HAWAII-1 devices developed by Rockwell, but with an extended detector
array size of 2048×2048. The device was designed for use in the
AEOS spectrograph, a cross-dispersed spectrograph intended to cover a
large spectral range in a single exposure, therefore, array size was
of paramount importance.
---------------------------------------------------------
Title: The New 1.7 m Off-Axis Solar Telescope (NST) Project: a Path
to Better Solar Science
Authors: Goode, P. R.; Didkovsky, L. V.; Kuhn, J.
2003AGUFMSH42B0532G Altcode:
Big Bear Solar Observatory (BBSO) of New Jersey Institute of Technology
is upgrading its 65 cm aperture vacuum telescope with a modern, off-axis
1.6 m clear aperture instrument - New Solar Telescope (NST). The NST
offers a significant incremental improvement in ground-based infrared
and visible light high angular resolution capabilities. It will fully
utilize the optical and dynamical range advantages of its unobstructed
(off-axis) pupil. The NST enhances our continuing program to understand
photospheric magneto-convection and chromospheric dynamics. This
new telescope will be the largest aperture solar telescope, and the
largest aperture off-axis telescope located in one of the best observing
sites. It will enable new, cutting edge science.
---------------------------------------------------------
Title: The Lyot Project: Toward Exoplanet and Circumstellar Disk
Imaging and Spectroscopy
Authors: Oppenheimer, B. R.; Digby, A. P.; Shara, M.; Brenner, D.;
Newburgh, L.; Makidon, R. B.; Sivaramakrishnan, A.; Soummer, R.;
Graham, J. R.; Kalas, P.; Perrin, M.; Kuhn, J. R.; Whitman, K.; Lloyd,
J. P.
2003AAS...20313604O Altcode: 2004BAAS...36Q.583O
We present the opto-mechanical design, expected performance, and a
progress report on the Lyot Project's new near-infrared coronagraph
designed and optimized to operate in tandem with the Advanced
Electro-Optical System at the Maui Space Surveilance System. This
coronagraph includes a number of novel features, such as active optical
alignment and a second stage tip/tilt loop. The in-lab construction
is nearly complete. We expect first light in March 2004, when we will
commence a survey for extremely faint objects, such as brown dwarfs
and large planets, and disks orbiting nearby stars. This instrument
will be more sensitive, by almost a factor of ten, than any other
existing instrument in the .2 to 1.5 arcsec range of separations from
the target stars. <P />The Lyot Project is funded by two grants from
the National Science Foundation. The US Air Force provides telescope
time, on-site support and 80% of the research funds for one of the
grants. The Project also benefits from the generosity of the American
Museum of Natural History's patrons.
---------------------------------------------------------
Title: Thermal IR Prospects for Coronal Magnetic Field Measurement
Authors: Kuhn, J. R.; Coulter, R.
2003AGUFMSH41D..06K Altcode:
The SOLARC Haleakala reflecting coronagraph was designed and built
for studying the IR solar corona. High dynamic range imaging and
spectroscopy in the thermal IR offers unique prospects for coronal
field measurements. Here we summarize the interesting opportunities,
our progress and results toward this goal.
---------------------------------------------------------
Title: Solar Radius Observer Satellite (SoROS)
Authors: Emilio, M.; Leister, N. V.; Teixeira, R.; Benevides-Soares,
P.; Kuhn, J.
2003ala..conf..177E Altcode:
It is known a long time ago that the Sun presents variations. The most
obvious of the manifestations is the variation of the solar spots in
his surface. With the invention of the telescope around 1600 regular
observations, but no systematic, of the solar surface began to be done
by several observatories in Europe. The manifestations of the activity
cycle in the production of solar energy are associated to the solar
wind, to the emission of particles and the magnetic fields on the solar
surface. While the energy of the solar wind is negligible compared
to the energy in the ultraviolet and in the visible, the relative
variations are significantly larger. But can those small fluctuations
of energy affect the climate? This mission aim to measure solar shape
and radius to test models to explain the variation of solar energy, help
to determine Sun's gravitational potential and its internal rotational
and for the first time, measure gmodes oscillations frequencies.
---------------------------------------------------------
Title: Um satélite brasileiro para observação do diâmetro solar
Authors: Emilio, M.; Leister, N. V.; Benevides Soares, P.; Teixeira,
R.; Kuhn, J.
2003BASBr..23..198E Altcode:
Propomos uma missão espacial para medir a forma e o diâmetro solar com
o objetivo de ajudar a determinar o potencial gravitacional do Sol e
a sua rotação com precisão, testar modelos teóricos de variação
de energia e pela primeira vez medir os modos g de oscilação. As
observações serão obtidas através do instrumento denominado APT
(Astrometric and Photometric Telescope) descrito por Kuhn(1983). A
sensibilidade do instrumento é de 0,2 mas em 27 dias para as
observações do diâmetro solar feitas a cada minuto. Esta é uma
missão de três anos de duração e pode complementar as medidas que
serão feitas pelo satélite PICARD (a ser lançado em 2007). Outros
parâmetros físicos podem ser obtidos com as mesmas imagens o que
certamente interessará à comunidade de física solar. Um primeiro
contato foi realizado com a agência espacial brasileira que pretende
lançar um satélite científico a cada dois anos.
---------------------------------------------------------
Title: Parametric Dwarf Spheroidal Tidal Interaction
Authors: Fleck, Jean-Julien; Kuhn, J. R.
2003ApJ...592..147F Altcode: 2003astro.ph..2463F
The time-dependent tidal interaction of the Local Group dwarf spheroidal
(dSph) galaxies with the Milky Way (MW) can fundamentally affect
their dynamical properties. The model developed here extends earlier
numerical descriptions of dSph-MW tidal interactions. We explore
the dynamical evolution of dSph systems in circular or elliptical MW
orbits in the framework of a parametric oscillator. An analytic model
is developed and compared with more general numerical solutions and
N-body simulation experiments.
---------------------------------------------------------
Title: 1.6 M Solar Telescope in Big Bear -- The NST
Authors: Goode, Philip R.; Denker, Carsten. J.; Didkovsky, Leonid I.;
Kuhn, J. R.; Wang, Haimin
2003JKAS...36S.125G Altcode:
No abstract at ADS
---------------------------------------------------------
Title: High Dynamic Range and the Search for Planets
Authors: Tokunaga, A. T.; Ftaclas, C.; Kuhn, J. R.; Baudoz, P.
2003IAUS..211..487T Altcode: 2002astro.ph..8328T
General arguments for optimized coronagraphy in the search for
planets are presented. First, off-axis telescopes provide the
best telescopic platforms for use with coronagraphy, and telescope
fabrication technology now allows the fabrication of such telescopes
with diameters of up to 6.5 m. We show that in certain circumstances
a smaller telescope with an off-axis primary has a signal-to-noise
advantage compared with larger Cassegrain telescopes. Second, to fully
exploit the advantages of the coronagraph for suppressing stray light,
it is necessary to use a high Strehl ratio adaptive optics system. This
can be best achieved initially with modest aperture telescopes of
3--4 m in diameter. Third, application of simultaneous differential
imaging and simultaneous polarimetric techniques are required to reach
the photon-limit of coronagraphic imaging. These three developments,
if pursued together, will yield significant improvements in the search
for planets.
---------------------------------------------------------
Title: The J- and K-Band Brightness of the Solar F Corona Observed
during the Solar Eclipse on 1998 February 26
Authors: Ohgaito, R.; Mann, I.; Kuhn, J. R.; MacQueen, R. M.;
Kimura, H.
2002ApJ...578..610O Altcode:
We analyze J- and K-band observations of the 1998 solar eclipse
and derive the F-corona brightness in the K band between 3 and
7 R<SUB>solar</SUB> from the center of the Sun and in the J band
out to 5 R<SUB>solar</SUB>. The falloff in the K-band brightness
from 3 to 7 R<SUB>solar</SUB> is fitted with a radial power law
with exponent -2.4+/-0.1 at the solar equator and with exponent
-2.9<SUP>+0.2</SUP><SUB>-0.1</SUB> at the solar pole. This slope is
gentler than that derived from observations in 1983 but is steeper
than that derived from observations for the 1991 eclipse. The radial
profiles agree well with models that explain the F corona with weakly
absorbing dust particles. Comparison of the J- and K-band brightness at
3 R<SUB>solar</SUB> from the center of the Sun indicates a reddening
of the F corona with respect to the solar spectrum. The reddening is,
however, less pronounced compared to the F corona observed during the
1983 total solar eclipse. This fact may be attributed to a change in
the composition of dust near the Sun. As with the radial profiles, the
reddening in 1998 is better explained with models that assume weakly
absorbing rather than strongly absorbing dust particles in the solar
corona. Similar to recent eclipse observations, we do not detect an
excess emission feature of near-solar dust in the F corona. We hence
can reject the hypothesis that suggests a correlation between the
detection of an emission feature and the solar activity cycle.
---------------------------------------------------------
Title: Sunspot bright rings - a probe into thermal conduction in
the solar convection zone
Authors: Armstrong, J. D.; Kuhn, J. R.
2002AAS...200.9102A Altcode: 2002BAAS...34..953A
The conductivity derived from mixing length theory has often been
used as an arguement that energy which one might consider "blocked"
by a sunspot, is quickly distributed through out the convection zone
and radiated over the thermal times scale of the convection zone. In
a complimentary view, facular regions are thought of as bright regions
which draw upon the thermal reserves of the entire convection zone. We
examine the bright rings seen around sunspots, and by comparing to
simple conductive models show that thermal perterbations in convective
regions do not behave in this manner.
---------------------------------------------------------
Title: Solar Irradiance Variations over Solar Cycles 21 to 23
Authors: Pap, J. M.; Kuhn, J.; Jones, H.; Turmon, M.; Arge, N.;
Schmutz, W.; Floyd, L.
2002AAS...200.2803P Altcode: 2002BAAS...34..679P
In this paper we describe the science requirements and a new measurement
strategy to better understand solar variability and its potential effect
on climate. We study the relation between the variations in solar total
and UV irradiances and solar magnetic fields as observed within the last
three decades. The results of our analysis raise important questions:
(1) is there a significant non-magnetic component in the observed
irradiance variations?; (2) may polar magnetic fields play a role
in irradiance changes?; (3) is there a strict linear relationship
between solar variability and irradiance variations as the current
irradiance models used in climate studies assume? The results presented
in this paper underscore the need to further develop new measurement
and analysis techniques to study and predict the climate impact of
solar variability.
---------------------------------------------------------
Title: The Solar Cycle as a Delayed Oscillator
Authors: Kuhn, J. R.; Armstrong, J. D.
2002AAS...200.8905K Altcode: 2002BAAS...34R.791K
Solar luminosity and irradiance variations provide an important
constraint on the physics of the solar cycle. Starting from magnetic
flux-transport models of the solar cycle it is possible to reproduce
many of the features of the magnetic, irradiance, and acoustic solar
cycle observables. This talk will describe how a “delayed oscillator"
model could explain the magnetic cycle.
---------------------------------------------------------
Title: Long-term solar irradiance variations: results and perspectives
Authors: Pap, J.; Fleck, B.; Frohlich, C.; Jones, H.; Kuhn, J.;
Schmutz, W.
2002cosp...34E.553P Altcode: 2002cosp.meetE.553P
In this paper we show the recent result on irradiance variations and
their relation to solar magnetic activity over solar cycles 21 to
23. Comparison of the multi-decade long irradiance and magnetic field
measurements indicates that the shape and magnitude of irradiance
variations are different from that of magnetic indices. Specifically,
while magnetic indices show that solar cycle 23 is weaker than the two
previous cycles, the long-term variation of total solar irradiance
over solar cycles 21 to 23 is rather symmetrical, showing that its
maximum and minimum levels were about the same within their measuring
uncertainties. These results raise questions like: (1) is there a
strict linear relationship between solar variability and irradiance
variations as the current irradiance models used in climate studies
assume?; (2) what is the role of polar magnetic fields in irradiance
changes?; (3) is there a significant non-magnetic component in the
observed irradiance variations? The results presented in this paper
underscore the need to further develop new measurement and analysis
techniques to study and predict the climate impact of solar variability.
---------------------------------------------------------
Title: Solar radius variations over the solar cycle: ground and
space experiments
Authors: Emilio, M.; Leister, N.; Kuhn, J.; Bush, R.; Benevides-Soares,
P.
2002cosp...34E2798E Altcode: 2002cosp.meetE2798E
An astrolabe observational program at São Paulo measures the solar
radius since 1974. Several ground experiments, including astrolabes,
show correlations between solar radius and solar magnetic activit. A
curious fact is that some measures in the ground show amplitude of
the order of 0.1 sec during the solar cycle. Theoretical forecasts,
heliosismologic observations and measurements made with SOHO satellite
shows that the amplitude of the radius variation must be of at least
one magnitude order lower. Would be these instruments measuring a
variation of the terrestrial atmosphere instead variation of the
solar radius? Errors of atmospheric refraction using astrolabes are
of second order. Theoretically, the first order errors vanish doing
the subtraction of the zenithal distances between upper and lower
solar limbs. Those of second order include possible variations of
atmospheric refraction in the interval of contact of each limb that
are about of 4 minutes. Could the atmospheric turbulence vary during
the solar cycle and explain the amplitude of the variation observed in
the radius made by the ground experiments? It is known that the solar
magnetic cycle intervenes with our atmosphere but still there is not a
model describing in details how this variation happens. We present hear
a study about the divergences among the space and ground experiments.
---------------------------------------------------------
Title: Physical mechanisms of the irradiance solar cycle
Authors: Kuhn, J.; Armstrong, J.
2002cosp...34E.695K Altcode: 2002cosp.meetE.695K
Despite more than two decades of satellite solar irradiance observations
we are unable to answer important questions like, could the next solar
cycle be three times larger than the current? Basic questions like,
is the cycle phase-amplitude variability a consequence of strongly
non-linear chaotic behavior or does the cycle result from stochastic
driving of a weakly non-linear system? (as Babcock and Leighton
suggested many years ago), have not been resolved. Finding a physical
model which simultaneously accounts for the Sun's photometric and
magnetic variability may be key to answering these questions. This
paper explores the physical connections between the global solar cycle
and the physical mechanisms of irradiance and magnetic variability.
---------------------------------------------------------
Title: Concepts for a Large-Aperture, High Dynamic Range Telescope
Authors: Kuhn, J. R.; Moretto, G.; Racine, R.; Roddier, F.; Coulter, R.
2001PASP..113.1486K Altcode:
This paper summarizes concept studies for a large telescope capable
of wide-field imaging and of the highest possible dynamic range for
photometry and angular resolution. Point-spread functions (PSFs) and
scattered light levels at large offsets are computed and compared
for four telescopes of the same light-gathering power but with
different pupil functions:1. a reference monolithic mirror telescope
with a 17.4 m primary,2. a segmented mirror telescope (SMT) with a
hexagonally segmented primary,3. a hexagonal off-axis telescope (HOT)
with a distributed aperture made of 6×6.5 m unobstructed circular
mirrors that are identical off-axis sections of a parent 20 m mirror,
and4. a square off-axis telescope (SOT) whose aperture is made of 4×8
m off-axis mirrors. The characteristics of the PSFs are examined in
the diffraction- and seeing-limited regimes, assuming (1) perfect
mirror figure and (2) realistic figure errors (edge defects). The
implications of field rotation with an altitude-azimuth mounting
are discussed in each case. The implementation of adaptive optics
(AO) and the properties of AO-compensated PSFs having a Strehl
ratio of 0.5, and of coronagraphic imaging, are also discussed for
the four configurations. It is shown that, in the seeing-limited
regime and as intuitively expected, the optical performance of all
four telescopes is comparable. With higher order adaptive optics and
for coronagraphic observations, the SOT and HOT are superior to the
SMT. This distinction becomes larger with relaxed constraints on mirror
edge-polishing requirements. A full optical design is presented for the
novel HOT configuration, and optical fabrication issues are briefly
addressed. Finally, science programs and possible instrumentation
layouts with the HOT are briefly explored for different modes of
operation. It appears that the natural “optical bench” configuration
of the HOT can provide a remarkably versatile and convenient environment
for instrument deployment.
---------------------------------------------------------
Title: Solar Radius Observations by the Michelson Doppler Imager
Authors: Bush, R. I.; Chu, K.; Kuhn, J. R.
2001AGUFMSH11B0715B Altcode:
The Michelson Doppler Imager (MDI) instrument on the SOHO spacecraft is
approaching the completion of six years of observing the Sun. During
this period, full disk continuum images with 4 arc-second resolution
have been taken at a cadence of at least four images per day. Because
of the absence of atmospheric blurring and the stable environment
of the L1 halo orbit, these images provide a long term measurement
of the solar limb. The determination of changes in the solar radius
from these images is affected by both an annual thermal variation in
the MDI front entrance window and by a slow shift in the instrument
focus due to aging of the entrance bandpass filter. These effects are
being modeled in order to determine an estimate of the solar cycle
variation in the solar radius. This research is supported by NASA
grant NAG5-10483 at Stanford University.
---------------------------------------------------------
Title: Erratum: He I 10830 Å Line Polarimetry: A New Tool to Probe
the Filament Magnetic Fields
Authors: Lin, Haosheng; Penn, Matt J.; Kuhn, Jeffrey R.
2001ApJ...560..534L Altcode:
In the paper “He I 10830 Å Line Polarimetry: A New Tool to Probe
the Filament Magnetic Fields” by Haosheng Lin, Matt J. Penn, and
Jeffrey R. Kuhn (<A href="/abs/1998ApJ...493..978">ApJ, 493, 978
[1998]</A>), several mathematical and typographical errors escaped
the authors' attention. These are mostly errors in the scaling
factor of the expressions, however, and they did not affect the
results of the paper. 1. There was an error in the scaling factor
in the right-hand side of equation (4). The correct expression for
equation (4) should be E<SUB>S</SUB>(r,ω,t)=-e(ω/c)<SUP>2</SUP>
(e<SUP>-i(ωt-k˙r)</SUP>)/r × r×x(ω) . This error propagated into
the paper and affected several equations derived later on. First,
the correct expression for equation (33) (and eq. [A24])
should be N(ω)~((ω<SUB>0</SUB>)/2m)(e/c)<SUP>2</SUP>1)/
(ω<SUB>0</SUB>-ω)+iΓ/2) Accordingly, the correction
expressions for equations (34), (35), and (36) are
NN<SUP>*</SUP>=1/4((ω<SUB>0</SUB>)/m)<SUP>2</SUP>(e/c)<SUP>4</SUP>
1/(ω<SUB>0</SUB>-ω)<SUP>2</SUP>+(Γ/2)<SUP>2</SUP>),
Re(iNN<SUP>*</SUP>)=1/4((ω<SUB>0</SUB>)/m)<SUP>2</SUP>
((e/c)<SUP>4</SUP>Γ/2)/[(ω<SUB>0</SUB>-ω)<SUP>2</SUP>+
(Γ/2)<SUP>2</SUP>]<SUP>2</SUP>,
Im(iNN<SUP>*</SUP>)=1/4((ω<SUB>0</SUB>)/m)<SUP>2</SUP>
(e/c)<SUP>4</SUP>(ω<SUB>0</SUB>-ω)/[(ω<SUB>0</SUB>-
ω)<SUP>2</SUP>+(Γ/2)<SUP>2</SUP>]<SUP>2</SUP> Similarly, this
correction should be applied to the coefficient of equations (A25),
(A26), and (A37). That is, the factor (eω<SUB>0</SUB>/2m)<SUP>2</SUP>
in equations (A25), (A25), and (A37) should be replaced by
(1/4)(ω<SUB>0</SUB>/m)<SUP>2</SUP>(e/c)<SUP>4</SUP>. Finally,
the correct expressions for the Doppler-broadened profiles
h(a,v), k(a,v), and f(a,v) in equations (39), (40),
and (41) should be h(a,v)=3/8(sqrt(π)e<SUP>2</SUP>)/mc
1/(▵ω<SUB>D</SUB>) a/πΣ<SUB>-∞</SUB><SUP>∞</SUP>
(e<SUP>-y^2</SUP>dy)((v-y)<SUP>2</SUP>+a<SUP>2</SUP>) =
3/8(sqrt(π)e<SUP>2</SUP>)/mc 1/(▵ω<SUB>D</SUB>) H(a,v),
k(a,v)=3/4(sqrt(π)e<SUP>2</SUP>)/mc 1/(▵ω<SUP>2</SUP><SUB>D</SUB>)
(a<SUP>2</SUP>)/πΣ<SUB>-∞</SUB><SUP>∞</SUP>
(e<SUP>-y^2</SUP>dy)([(v-y)<SUP>2</SUP>+a<SUP>2</SUP>]<SUP>2</SUP>),
f(a,v)=3/4(sqrt(π)e<SUP>2</SUP>)/mc
1/(▵ω<SUP>2</SUP><SUB>D</SUB>) πΣ<SUB>-∞</SUB><SUP>∞</SUP>
((v-y)e<SUP>-y^2</SUP>dy)([(v-y)<SUP>2</SUP>+a<SUP>2</SUP>]<SUP>2</SUP>.
2. The h<SUP>2</SUP> factor in equations (17), (22), and
(23) should be removed. 3. The sentence after equation (7)
should read “The oscillator solution can be written as
X(ω)=e<SUP>-1</SUP>(ω/c)<SUP>-2</SUP>NE<SUB>I</SUB>.”
---------------------------------------------------------
Title: Imaging Polarimetric Observations of a New Circumstellar
Disk System
Authors: Kuhn, J. R.; Potter, D.; Parise, B.
2001ApJ...553L.189K Altcode: 2001astro.ph..5239K
Few circumstellar disks have been observed directly. Here we use
sensitive differential polarimetric techniques to overcome atmospheric
speckle noise in order to image the circumstellar material around HD
169142. The detected envelope or disk is considerably smaller than
expectations based on the measured strength of the far-IR excess from
this system.
---------------------------------------------------------
Title: Physical Mechanisms of Solar Irradiance and Luminosity
Variations
Authors: Kuhn, J. R.
2001AGUSM..SP31B05K Altcode:
The solar irradiance and luminosity changes observed over the last
two decades measure distinct physical mechanisms, each triggered
differently by solar magnetic fields. The irradiance fluctuations,
associated with sunspots and bright faculae, are more aptly described
as extremes from a range of magnetic perturbations which includes the
magnetic network. We use accurate photometry from the ground and space
to illustrate this and to show how proxy measurements using CaII K or
magnetic flux density data can go awry while trying to identify the
mechanisms of solar variability. Very precise, spatially resolved, solar
surface brightness observations are a critical tool for understanding
stellar convection, and in particular how the base of the convection
zone evolves with the solar magnetic cycle. It is likely that our
understanding and ability to predict the importance of solar irradiance
variations, for example, for the terrestrial climate system, will depend
on future surface brightness data of similar and improved accuracy.
---------------------------------------------------------
Title: Coronagraphy with the AEOS High Order Adaptive Optics System
Authors: Lloyd, J. P.; Graham, J. R.; Kalas, P.; Oppenheimer, B. R.;
Sivaramakrishnan, A.; Makidon, R. B.; Macintosh, B. A.; Max, C. E.;
Baudoz, P.; Kuhn, J. R.; Potter, D.
2001AAS...198.7703L Altcode: 2001BAAS...33Q.902L
Adaptive Optics has recently become a widely used technique to acquire
sensitive, diffraction limited images in the near infrared with
large ground based telescopes. Most astronomical targets are faint;
driving astronomical AO systems towards large subapertures; resulting
in a compromise between guide star brightness, observing wavelength,
resolution and Strehl ratio. Space surveilance systems have recently
been developed that exploit high order adaptive optics systems to
take diffraction limited images in visible light on 4 meter class
telescopes on bright (V<8) targets. There is, however, a particular
niche that can be exploited by turning these visible light space
surveillance systems to astronomical use at infrared wavelengths. At
the longer wavelengths, the strehl ratio rises dramatically, thus
placing more light into the diffracted Airy pattern at the expense
of the atmospheric halo. A coronagraph can be used to suppress the
diffracted light, and observe faint companions and debris disks around
nearby, bright stars. Observations of these very high contrast objects
benefit greatly from much higher order adaptive optics systems than
are presently available to the astronomical commnunity. The National
Science Foundation and Air Force Office of Scientific Research is
sponsoring a program to conduct astronomical observations at the AEOS
facility. We are presently developing an astronomical coronagraph to be
deployed at the Air Force AEOS facility. We describe the coronagraph,
and discuss the advantages and limitations of ground based high order
AO for high contrast imaging.
---------------------------------------------------------
Title: An Off-axis Telescope Concept for High Contrast Imaging
Authors: Tokunaga, A. T.; Kuhn, J.; Baudoz, P.; Coulter, R.; Rayner,
J.; Toomey, D.; Moretto, G.
2001AAS...198.7710T Altcode: 2001BAAS...33..903T
A telescope concept is proposed to undertake studies of Kuiper Belt
Objects, Near-Earth Objects, and circumstellar disks and extra-solar
planets. These diverse scientific objectives require capabilities
ranging over wide-field imaging, high angular resolution, high
sensitivity in the optical and thermal infrared, and superb photometric
dynamic range. It is possible to achieve all of these performance
requirements using a 6.5m unobstructed, off-axis telescope. Unique
features include optimization for unprecedented low scattered light
and high dynamic range astronomy, extremely low infrared emissivity,
and innovative instruments uniquely designed to take full advantage
of these capabilities, such as coronagraphic instruments.
---------------------------------------------------------
Title: Limits on Lyot coronagraphy with AEOS adaptive optics telescope
Authors: Sivaramakrishnan, A.; Makidon, R. B.; Lloyd, J. P.;
Oppenheimer, B. R.; Graham, J. R.; Kalas, P. G.; Macintosh, B. A.;
Max, C. E.; Baudoz, P.; Kuhn, J.; Potter, D.
2001AAS...198.7705S Altcode: 2001BAAS...33..902S
The 3.6m Air Force Electo-Optical System telescope is the most advanced
adaptive optics (AO) system available to the astronomical community. Its
941-channel AO system feeds several stable instrument platforms at
a very slow Cassegrain focus. Its small secondary obscuration makes
it ideal for AO coronagraphy. We present estimates of current and
theoretical limits on dynamic range using a diffraction-limited Lyot
coronagraph optimized for the 3.6m AEOS telescope. We incorporate both
the effects of imperfect AO correction of the wavefront and telescope
guiding errors in our simulations. We calculate limits on faint
companion detection (in the H-band) for this system at separations
between 0.36 and 1.3 arcseconds.
---------------------------------------------------------
Title: One solar cycle later: reflections and speculations on
directions in helio- and asteroseismology in a new millennium
Authors: Kuhn, J. R.
2001ESASP.464....7K Altcode: 2001soho...10....7K
This talk reflects on our progress since the last helioseismology
symposium held here in Tenerife over one solar cycle ago. While
even a superficial inspection shows that the last decade of seismic
investigation of the Sun and other stars has been enormously revealing
- it appears that new observations are generating new questions at a
faster rate than our ability to solve old problems. Here we briefly
review some of this progress, and highlight questions and research
directions that might possibly be described at the next Tenerife
helioseismology meeting.
---------------------------------------------------------
Title: MDI-SOHO Measures of Solar Radius Variation
Authors: Emilio, M.; Kuhn, J. R.; Bush, R. I.; Scherrer, P.
2001IAUS..203..101E Altcode:
Why does the solar luminosity vary and could it change on human
timescales by enough to affect terrestrial climate? As important as
these questions are, we lack answers because we do not understand the
physical mechanisms which are responsible for the solar irradiance
cycle. Progress here depends on discovering how changes in the solar
interior affect energy flow from the radiative and convection zones out
through the photosphere. Measurements of small changes in the solar
radius are a critical probe of the Sun's interior stratification and
can tell us how and where the solar luminosity is gated or stored. Here
we report results from a sensitive 3 year satellite experiment designed
to detect solar diameter fluctuations.
---------------------------------------------------------
Title: Tidal Disruptions of the Ursa Minor and Draco Dwarf Spheroidal
Galaxies
Authors: Kocevski, D. D.; Kuhn, J. R.
2000AAS...197.3004K Altcode: 2000BAAS...32.1446K
Several of the local group dwarf spheroidal (dS) galaxies show evidence
of inflated velocity dispersions. A likely model for Ursa Minor,
Carina, and Draco is that their tidal interaction with the Milky Way has
pushed them far from virial equilibrium. We have obtained wide-field
V and I band photometry of the Ursa Minor and Draco dS galaxies using
the 12K CCD mosaic detector on the Canada-France-Hawaii telescope. We
present here the results of a sensitive search for extratidal stars
out to distances of 4 degrees from the centers of these galaxies. We
discuss the implications of these results for dark matter and Milky
Way tidal interaction models.
---------------------------------------------------------
Title: Using Precise Solar Limb Shape Measurements to Study the
Solar Cycle
Authors: Kuhn, J. R.; Floyd, L.; Fröhlich, C.; Pap, J. M.
2000SSRv...94..169K Altcode:
Despite 20 years of total solar irradiance measurements from space, the
lack of high precision spatially resolved observations limits definitive
answers to even simple questions like “Are the solar irradiance changes
caused solely by magnetic fields perturbing the radiative flux at the
photosphere?" More subtle questions like how the aspheric structure
of the sun changes with the magnetic cycle are only now beginning to
be addressed with new tools like p-mode helioseismology. Solar 5-min
oscillation studies have yielded precise information on the mean radial
interior solar structure and some knowledge about the rotational
and thermal solar asphericity. Unfortunately this progress has not
been enough to generate a self-consistent theory for why the solar
irradiance and luminosity vary with the magnetic cycle. We need sharper
tools to describe and understand the sun's global aspheric response
to its internal dynamo, and we need to be able to measure the solar
cycle manifestation of the magnetic cycle on entropy transport from
the interior to the photosphere in much the same way that we study the
fundamentally more complex problem of magnetic flux transport from the
solar interior. A space experiment called the Solar Physics Explorer for
Radius, Irradiance and Shape (SPHERIS) and in particular its Astrometric
and Photometric Telescope (APT) component will accomplish these goals.
---------------------------------------------------------
Title: A Least-squares Solution for the Effective Conductivity of
the Solar Convection Zone
Authors: Kuhn, J. R.; Georgobiani, D.
2000SSRv...94..161K Altcode:
Here we show how realistic numerical simulations of solar convection can
be parameterized with an effective thermal conductivity tensor. We show
that this diffusive approximation yields an accurate statistical (in the
sense of the χ^2 test) description of the thermal transport properties
of a perturbed solar convection zone. This parameterization will allow
more accurate large scale solar irradiance and luminosity calculations.
---------------------------------------------------------
Title: On the Constancy of the Solar Diameter
Authors: Emilio, M.; Kuhn, J. R.; Bush, R. I.; Scherrer, P.
2000ApJ...543.1007E Altcode:
Why does the solar luminosity vary and could it change on human
timescales by enough to affect terrestrial climate? As important as
these questions are, we lack answers because we do not understand the
physical mechanisms responsible for the solar irradiance cycle. Progress
here depends on discovering how changes in the solar interior affect
energy flow from the radiative and convection zones out through the
photosphere. Measurements of small changes in the solar radius are a
critical probe of the Sun's interior stratification; they can tell us
how and where the solar luminosity is gated or stored. Here we report
results from a sensitive 3 yr satellite experiment designed to detect
solar diameter fluctuations.
---------------------------------------------------------
Title: Physical Causes of Solar Variability - Discussion Session 1b
Authors: Kuhn, J. R.; Schüssler, M.
2000SSRv...94..177K Altcode:
This report is divided into three parts: Section 1 gives a short
introduction and a summary of the topics discussed. Section 2
is a position statement by J. Kuhn on the interpretation of the
irradiance measurements, while Section 3 gives a position statement
by M. Schüssler discussing observations of stars that could be useful
for understanding solar variability.
---------------------------------------------------------
Title: Solar Interior: Solar Diameter, Oblateness and Temperature
Authors: Kuhn, J.
2000eaa..bookE2245K Altcode:
The visible edge of the Sun is called the LIMB and is almost circular,
but very small deviations from a spherical Sun are measurable. The
largest deviation is a `flattening' of the polar radius in comparison
to the equatorial solar radius. The Sun's surface temperature is also
not spherically symmetric but has a tiny asphericity in the form of
a latitudinal temperature variation. The radius, sha...
---------------------------------------------------------
Title: Global Solar Corona Revealed by Time Series Observations
Authors: Li, Jing; Kuhn, J.; LaBonte, B.; Raymond, J. C.; Acton, L. W.
2000ApJ...538..415L Altcode:
Time series observations at UV (Extreme Ultraviolet Imaging
Telescope/Solar and Heliospheric Observatory) and X-ray (Soft
X-Ray Telescope/Yohkoh) wavelengths reveal properties of the global
solar corona that are not easily identified in a single image. A
median-filtering technique that rejects features varying with time
is used to isolate background corona. The coronal hole boundaries,
polar plumes, and polar rays in the inner corona are clearly seen in
Extreme Ultraviolet Imaging Telescope data over 5 months during the
last solar minimum (1996 January through May). For the first time,
we provide physical evidence for coronal hole boundaries in the
inner corona. The observations show clearly that the polar coronal
holes expand divergently with height. A simple latitudinal and radial
electron density distribution for the inner corona is found.
---------------------------------------------------------
Title: Rossby waves on the Sun as revealed by solar `hills'
Authors: Kuhn, J. R.; Armstrong, J. D.; Bush, R. I.; Scherrer, P.
2000Natur.405..544K Altcode:
It is a long-standing puzzle that the Sun's photosphere-its visible
surface-rotates differentially, with the equatorial regions rotating
faster than the poles. It has been suggested that waves analogous to
terrestrial Rossby waves, and known as r-mode oscillations, could
explain the Sun's differential rotation: Rossby waves are seen in
the oceans as large-scale (hundreds of kilometres) variations of
sea-surface height (5-cm-high waves), which propagate slowly either
east or west (they could take tens of years to cross the Pacific
Ocean). Calculations show that the solar r-mode oscillations have
properties that should be strongly constrained by differential
rotation. Here we report the detection of 100-m-high `hills' in the
photosphere, spaced uniformly over the Sun's surface with a spacing of
(8.7 +/- 0.6) × 10<SUP>4</SUP>km. If convection under the photosphere
is organized by the r-modes, the observed corrugated photosphere is
a probable surface manifestation of these solar oscillations.
---------------------------------------------------------
Title: Development Status of the Microshutter Arrays for the NGST MOS.
Authors: Moseley, S. H.; Fettig, R. K.; Kuhn, J.; Kutyrev, A. S.; Li,
M.; Mott, D. B.; Schwinger, D. S.; Wesenberg, R. P.; Woodgate, B. E.
2000AAS...196.3216M Altcode: 2000BAAS...32..722M
We are developing a two-dimensional array of microshutters that can be
used as a high efficiency, high contrast field selection device for
a multi-object spectrometer for the Next Generation Space Telescope
(NGST). The device is a close-packed array of randomly selectable
shutters with a cell size of 100 microns square and area filling factor
of about 80% produced in a 100 micrometer thick silicon wafer. Each
shutter, made of silicon nitride with an appropriate optical coating,
pivots on a torsion flexure along one edge. A CMOS circuit embedded
in the frame around the shutters allows independent individual
selection. An original double-shutter mechanism is employed for
actuation. It has been tested on a small size three by three shutter
array. Processing includes anisotropic back etching for wafer thinning,
an Inductive Coupled Plasma (ICP) back etch through the silicon to
the mechanical active nitride membrane and a Reactive Ion Etching
(RIE) to produce the shutters out of the nitride membrane. The layout
is based on a detailed mechanical analysis for which we determined
crucial material parameters experimentally. Our current array size is
128x128. We expect to have working arrays by the end of this year. This
project has been supported by NASA grants.
---------------------------------------------------------
Title: Microshutter Arrays for the Multi-Object Spectrometer on NGST
Authors: Moseley, S. H.; Bowers, C. W.; Fettig, R. K.; Gardner, J. P.;
Kimble, R. A.; Kuhn, J.; Kutyrev, A. S.; Malumuth, E. M.; Mentzell,
E. E.; Mott, D. B.; Schwinger, D. S.; Teplitz, H. I.; Wesenberg,
R. P.; Woodgate, B. E.
2000AAS...196.2302M Altcode: 2000BAAS...32R.705M
We present a concept for a high-efficiency, wide-band, multi-object
near-infrared spectrograph for the NGST. The spectrograph will
simultaneously cover the wavelength range of 0.6-5 microns with a 4K
by 4K mosaic array of InSb detectors and will offer low resolution
spectroscopy (R=25 - 100) of thousands of objects simultaneously,
higher resolution spectroscopy (R ~1500) of about a thousand objects
simultaneously, and an imaging mode for initial target acquisition
and configuration of a high transmission entrance aperture mask. The
key component of the spectrometer is the entrance aperture mask, a
programmable microshutter array. We have demonstrated basic mechanical
and electrostatic cell operation of a 3 by 3 array. We are currently in
the process of scaling it up to large arrays. The first working large
size arrays are expected to be tested by the end of this year. Our
spectrograph conceptual design includes two principal features
to address the demanding scientific requirements of the NGST, whose
primary targets will typically be highly redshifted and extremely faint:
1) our lowest resolution spectrograph design is based on refractive
dispersing elements (prisms) that permit us to obtain spectra over the
entire near-IR range of 0.6-5 microns ( 3 octaves) simultaneously for
all objects observed, rather than the 1 octave of coverage (to avoid
order confusion) available with a typical grating spectrograph. The use
of prisms as the only transmissive or dispersing elements, provides both
substantially higher throughput than grating/order sorter combinations
as well as the significant multiplexing advantage of complete wavelength
coverage in one exposure, 2) for higher resolutions than those available
to prisms, we evaluate the trade-off between using 3 or first order
gratings for R ~1500 and a prism cross-dispersed echelle for R ~5000.
---------------------------------------------------------
Title: A Least-Squares Solution for the Effective Conductivity of
the Solar Convection Zone
Authors: Kuhn, J. R.; Georgobiani, D.
2000svc..book..161K Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Using Precise Solar Limb Shape Measurements to Study the
Solar Cycle
Authors: Kuhn, J. R.; Floyd, L.; Fröhlich, C.; Pap, J. M.
2000svc..book..169K Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Tunable Filters on NGST
Authors: Satyapal, S.; Greenhouse, M. A.; Barclay, R.; Amato, D.;
Arritt, B.; Barry, R.; Holt, C.; Kuhn, J.; Higelman, T.; Fonneland,
N.; Lesyna, L.
2000ASPC..207..212S Altcode: 2000ngst.conf..212S
No abstract at ADS
---------------------------------------------------------
Title: Physical Causes of Solar Variability
Authors: Kuhn, J. R.; Schussler, M.
2000svc..book..177K Altcode:
No abstract at ADS
---------------------------------------------------------
Title: The Tunable Filter Program for NGST
Authors: Satyapal, S.; Greenhouse, M. A.; Barclay, R.; Amato, D.;
Arritt, B.; Barry, R.; Holt, C.; Kuhn, J.; Higeiman, T.; Fonneland,
N.; Lesnya, L.
2000ASPC..195..437S Altcode: 2000iutd.conf..437S
No abstract at ADS
---------------------------------------------------------
Title: A New Planetary Telescope Concept
Authors: Joseph, R. D.; Kuhn, J. R.; Tokunaga, A.; Coulter, R.;
Ftaclas, C.; Graves, J. E.; Hull, C.; Jewitt, D.; Mickey, D.; Moretto,
G.; Neill, D.; Northcott, M.; Roddier, F.; Roddier, C.; Siegmund,
W.; Owen, T.
1999DPS....31.5943J Altcode: 1999BAAS...31.1591J
The NASA IRTF is arguably the only ground-based telescope in the
world dedicated to planetary astronomy. Two decades of improvement
in infrared array technology, adaptive optics, and large mirror
fabrication techniques now make it imperative that the future needs
of NASA's Planetary Astronomy program be considered in the context of
the capabilities now possible for a modern telescope. In response to
a suggestion from NASA Headquarters we have developed an innovative
telescope concept which provides unique and unsurpassed scientific
capabilities to the planetary community. We call this facility the New
Planetary Telescope (NPT). We have assumed that the main objectives
for the NPT are studies of Kuiper Belt Objects, Near-Earth Objects,
studies of circumstellar disks and extra-solar planets, and ground-based
support for NASA flight missions. These diverse scientific objectives
require capabilities ranging over wide-field imaging, high angular
resolution, high sensitivity in the optical and thermal infrared,
and superb photometric dynamic range. This study shows that it is
possible to achieve all of these performance requirements using a
6.5m unobstructed, off-axis telescope. This concept has compelling
natural advantages for adaptive optics, coronagraphic astronomical
imaging, and thermal infrared imaging. Unique features of the NPT
include wide-field imaging capability, with a field-of-view of at
least two degrees, optimization for unprecedented low scattered light
and high dynamic range astronomy, extremely low infrared emissivity,
and innovative instruments uniquely designed to take full advantage
of these capabilities. This telescope concept breaks new ground
in telescope technology, and it is therefore an ideal technical
development project for NASA. NASA is currently at the forefront
of development in interferometry using the Keck telescopes. The NPT
complements and enhances this program since it provides an important
baseline to add to those already planned on Mauna Kea. Moreover, the
NPT is the ideal telescope for a full-fledged optical/infrared array
of interferometric telescopes.
---------------------------------------------------------
Title: Tunable Filters for NGST
Authors: Satyapal, S.; Greenhouse, M.; Barry, R.; Barclay, R.;
Amato, D.; Arritt, B.; Harvey, V.; Holt, C.; Kuhn, J.; Fonneland,
N.; Lesyna, L.
1999AAS...195.8606S Altcode: 1999BAAS...31Q1501S
Tunable filters will enhance the spectral resolution, sensitivity, and
field of view capabilities of a number of potential science instruments
on NGST. They will : 1) provide flexibility in wavelength and bandwidth
choice compared with a fixed inventory of filters in convential cameras,
2) improve the sensitivity of Fourier Transform Spectrometers when full
wavelength coverage imaging is not needed, and 3) provide a greater
multiplex advantage to multiobject spectrographs when limited spectral
coverage is desired. We display work in progress on a near-infrared
tunable bandpass filter for the wide field camera of the Next Generation
Space Telescope (NGST) Integrated Science Instrument Module (ISIM). This
Demonstration Unit for Low Order Cryogenic Etalon (DULCE), is designed
to demonstrate a high efficiency scanning Fabry-Perot etalon operating
in interference orders 1-4 at 30 K with a high stability DSP based servo
control system. DULCE is currently the only available tunable filter for
low order cryogenic operation in the near-infrared. In this application,
scanning etalons will illuminate the focal plane arrays with a single
order of interference to enable wide field low resolution (50 <
R < 200) hyperspectral imaging over a wide range of redshifts.
---------------------------------------------------------
Title: Interpreting the Solar Limb Shape Distortions
Authors: Armstrong, James; Kuhn, J. R.
1999ApJ...525..533A Altcode:
Accurate measurements of the solar oblateness have recently been
obtained from the SOHO/MDI satellite experiment. The new data are
sufficiently accurate to measure nonnegligible multipole shape terms
of higher order than the oblateness. Here we extend earlier solar
limb shape calculations and compare the new data with the helioseismic
evidence for a complex internal solar rotation profile. We find that
the quadrupole (l=2) and hexadecapole (l=4) shape terms are marginally
inconsistent with the solar rotation data.
---------------------------------------------------------
Title: The J- and K-Band brightness of the solar F-corona observed
during the solar eclipse on February 26, 1998.
Authors: Ohgaito, R.; Mann, I.; Kuhn, J. R.; MacQueen, R. M.; Lin,
H.; Edmunds, D.
1999BAAS...31.1159O Altcode:
No abstract at ADS
---------------------------------------------------------
Title: The J- and K-Band Brightness of the Solar F-Corona Observed
During the Solar Eclipse on February 26, 1998
Authors: Ohgaito, R.; Mann, I.; Kuhn, J. R.; MacQueen, R. M.; Lin,
H.; Edmunds, D.
1999DPS....31.5502O Altcode:
The solar eclipse on February 26 1998 was observed from an open flying
aircraft at an altitude of almost 6 km above the Pacific about 800
km southwest from Panama City. The solar F-corona, produced by light
scattering and thermal emission from dust around the Sun, was observed
with a low atmospheric straylight level in the J and K-band over a field
of view of 7 degrees. The data show no indication for the existence of
pronounced brightness features in the solar F-corona, such as often
discussed as evidence for the existence of dust rings. The shape
of the corona is slightly elliptic but symmetric in the north-south
direction. The data show a reddening of the coronal brightness compared
to the solar spectrum. The color of the F-corona is influenced by the
temperature of dust particles, by their spatial distribution, as well
as by their size distribution that influences especially the forward
scattering that is seen in the corona from dust particles close to the
observer. We will discuss the color variation from the solar equator
to the solar pole and with distances from the Sun and compare it to
models of dust light scattering and thermal emission.
---------------------------------------------------------
Title: Probable Detection of a Bright Infrared Coronal Emission Line
of Si IX near 3.93 Microns
Authors: Kuhn, J. R.; MacQueen, R. M.; Streete, J.; Tansey, G.; Mann,
I.; Hillebrand, P.; Coulter, R.; Lin, H.; Edmunds, D.; Judge, P.
1999ApJ...521..478K Altcode:
We report here the probable detection of an emission line of Si
IX that was observed from an open C130 aircraft over the Pacific
Ocean during the 1998 total solar eclipse. Although the IR data
themselves are inconclusive because of the uncertainty in the precise
central wavelengths of the narrowband filters during the eclipse,
the consistency of the measured IR limb excess with simultaneous EUV
emission measured by SOHO/Coronal Diagnostic Spectrometer and the EUV
Imager Telescope support our detection claim. This line appears to
be the brightest IR coronal line yet observed, and its existence may
significantly improve future prospects for obtaining optical coronal
magnetic field measurements.
---------------------------------------------------------
Title: Some Astronomical Performance Advantages of Off-Axis Telescopes
Authors: Kuhn, J. R.; Hawley, S. L.
1999PASP..111..601K Altcode:
Measurements requiring very high photometric dynamic range, like
astronomical observations of faint objects near bright sources (e.g.,
extrasolar planet detection), are often limited by the scattered
light characteristics of the telescope. Although the light-gathering
power of recently built telescopes has increased dramatically,
their scattered light performance has not. We compare models and
measurements of telescope scattered light and discuss some of the
scientific and technical issues that suggest how a low scattered
light design could extend the scientific capabilities of moderate
(4 m aperture) telescopes.
---------------------------------------------------------
Title: The Tunable Filter Program for NGST
Authors: Satyapal, S.; Greenhouse, M. A.; Barclay, R.; Amato, D.;
Arritt, B.; Barry, R.; Holt, C.; Irish, S.; Kuhn, J.; Kutyrev, A.;
Morrel, A.; Higelman, T.; Fonneland, N.; Lesyna, L.
1999AAS...194.9109S Altcode: 1999BAAS...31..984S
We display work in progress on a near-infrared tunable bandpass filter
for the wide field camera of the Next Generation Space Telescope (NGST)
Integrated Science Instrument Module (ISIM). This Demonstration Unit
for Low Order Cryogenic Etalon (DULCE), is designed to demonstrate a
high efficiency scanning Fabry-Perot etalon operating in interference
orders 1-4 at 30 K with a high stability DSP based servo control
system. DULCE has heritage in a Northrop Grumman system designed
for 1st order operation at 300 K, and is being developed jointly
by GSFC and NGC as an option to satisfy NGST requirements. In this
application, scanning etalons will illuminate the focal plane arrays
with a single order of interference to enable wide field low resolution
(50 << R << 200) hyperspectral imaging over a wide range
of redshifts. We discuss specific science applications that will be
enabled by near-infrared tunable filters.
---------------------------------------------------------
Title: What can irradiance measurements tell us about the solar
magnetic cycle?
Authors: Kuhn, J. R.; Lin, H.; Coulter, R.
1999AdSpR..24..185K Altcode:
New full-disk satellite and ground-based experiments operating at
visible wavelengths can routinely produce solar photometric data of
sufficient accuracy to directly observe the photospheric signature
of total irradiance variations. Such data are likely to directly
test causal (as opposed to statistical) models of the irradiance
mechanisms. This is an important step, since without a physical
understanding of these changes we can neither predict nor rule out the
possibility of future (or past) large solar influences on the earth's
climate variability.
---------------------------------------------------------
Title: Near-Infrared Tunable Bandpass Filters for the NGST ISIM
Authors: Satyapal, S.; Greenhouse, M. A.; Barclay, R.; Amato, D.;
Arritt, B.; Barry, R.; Irish, S.; Kuhn, J.; Kutyrev, A.; Morell, A.;
Hilgeman, T.; Lesyna, L.; Fonneland, N.
1998AAS...193.3505S Altcode: 1998BAAS...30.1296S
We display work in progress on a near-infrared tunable bandpass filter
for the wide field camera of the Next Generation Space Telescope (NGST)
Integrated Science Instrument Module (ISIM). This Demonstration Unit
for Low Order Cryogenic Etalon (DULCE), is designed to demonstrate a
high efficiency scanning Fabry-Perot etalon operating in interference
orders 1-4 at 30 K with a high stability DSP based servo control
system. DULCE has heritage in a Northrop Grumman system designed for
1st order operation at 300 K, and is being developed jointly by GSFC
and NGC as an option to satisfy NGST requirements. In this application,
scanning etalons will illuminate the focal plane arrays with a single
order of interference to enable wide field low resolution (50 <
R < 200) hyperspectral imaging over a wide range of redshifts.
---------------------------------------------------------
Title: The sun's shape and brightness
Authors: Kuhn, J. R.; Bush, R. I.; Scherrer, P.; Scheick, X.
1998Natur.392..155K Altcode:
We present satellite data that show that the sun's shape and temperature
vary with latitude in an unexpectedly complex way. Although the solar
oblateness shows no evidence of varying with the solar cycle, we find
a significant hexadecapole shape term which may vary. We also see a
variation of about 1.5 K in the surface temperature with latitude. Based
on these results, we suggest that sensitive observations of brightness
variations be used as a record of the surface 'shadow' of cyclical
changes in the solar interior.
---------------------------------------------------------
Title: He i 10830 Angstrom Line Polarimetry: A New Tool to Probe
the Filament Magnetic Fields
Authors: Lin, Haosheng; Penn, Matt J.; Kuhn, Jeffrey R.
1998ApJ...493..978L Altcode:
In this paper, we present a new Stokes polarization observation of a
solar filament using the neutral helium line at 10830 Å. Similar to the
prominence Hanle effect, the polarization of the filament is due to the
resonant scattering and magnetic depolarization of the photospheric
radiation; it differs only in the scattering geometry. Since this
represents one of the first filament polarization observations, we
also present a classical derivation of a set of diagnostic formulae
that relate the filament polarization signals to the vector magnetic
field. <P />We measured the full Stokes profiles (I, Q, U, V) by
scanning the slit of the spectrograph parallel to the axis of a small
filament. In one section of the filament, the polarization signals
showed that the axial component of the magnetic field reverses direction
on either side of the filament axis. This axial field reversal is not
predicted by any of the existing magnetic field models of the filament,
nor was it observed by previous prominence Hanle effect observations. We
propose that a tilted magnetic field loop across the filament axis
can explain the observed axial field reversal. <P />This observation
also serves to demonstrate that measurements of the polarization of
the He I 10830 Å radiation from filaments is a useful new tool for
the diagnostics of filament magnetic field structures.
---------------------------------------------------------
Title: On the Origin of the Helioseismic Solar Cycle Variations
Authors: Kuhn, J. R.
1998ESASP.418..871K Altcode: 1998soho....6..871K
With more than one solar cycle's worth of measurements of helioseismic
variations, can we make sense of these changes? How much of the solar
cycle mechanism do we really understand -- particularly as to how
it affects the global acoustic, irradiance/luminosity, and outward
magnetic appearance of the sun? In combination with all of the solar
observables, what does the helioseismic data reveal (if anything) about
solar interior changes? This paper will highlight some of the relevant
measurements while attempting to illuminate the physical connections
between the local and global solar observations (as inferred from
helioseismic, photometric, and numerical experiments).
---------------------------------------------------------
Title: Importance of Monitoring Solar Global Properties: Luminosity,
Radius and Oscillations
Authors: Pap, J. M.; Kuhn, J. R.; Fröhlich, C.; Ulrich, R.; Jones,
A.; Rozelot, J. P.
1998ESASP.417..267P Altcode: 1998cesh.conf..267P
No abstract at ADS
---------------------------------------------------------
Title: Space-based near infrared coronal observations
Authors: Mann, I.; Kuhn, J. R.
1998AdSpR..21..315M Altcode:
We propose a set of observations of the near infrared coronal
brightness. Such a study allows unique measurements of the near
solar dust dynamics and material properties. In addition, recent
suggestions for a cool gas component in the corona will be investigated
by observations of the infrared neutral helium line. These observations
are difficult and require an upper atmospheric or satellite platform
to reduce the noise background.
---------------------------------------------------------
Title: Heat Transport in the Convective Zone and Deviations from
the Mixing Length Models
Authors: Georgobiani, D.; Kuhn, J. R.; Nordlund, AA.; Stein, R. F.
1998ESASP.418..771G Altcode: 1998soho....6..771G
For several decades, the heat transport in the solar convective
zone has been thought to be isotropic. Attempts to describe it in
terms of the mixing length theory seemed to be quite successful. In
contradiction with such an idealized picture, recent numerical
and observational data have demonstrated a highly non-isotropic,
inhomogeneous structure of the convective zone. This work presents the
results of calculations of the thermal conductivity in the convective
zone, using the numerical model of Stein-Nordlund. Thermal conductivity
is assumed to be a 3D tensor. Its vertical and horizontal diagonal
components differ in magnitudes for each given depth. Moreover, the
horizontal component stays negative, while increasing with depth. Both
features are naturally explained by the physical properties of the
solar convective zone. Implications for global questions of solar
convection are considered.
---------------------------------------------------------
Title: We must Choose the Simplest Physical Theory: LEVIN-LI-VITÁNYI
Theorem and its Potential Physical Applications
Authors: Fox, D.; Schmidt, M.; Koshelev, M.; Kreinovich, V.; Longpré,
L.; Kuhn, J.
1998mebm.conf..239F Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Sound speed variations near the photosphere due to entropy
perturbations in 3d numerical experiments
Authors: Georgobiani, D.; Kuhn, J. R.; Stein, R. F.
1997ASSL..225..127G Altcode: 1997scor.proc..127G
Results on how the temperature distribution near the solar photosphere
is altered by perturbing the entropy of rising fluid in the convection
zone several megameters below the surface, are presented. Effects on
the emergent intensity and implications for helioseismic observations
are described.
---------------------------------------------------------
Title: HE I 10830 A Line Polarimetry: A New Tool to Probe the Filament
Magnetic Fields
Authors: Lin, Haosheng; Penn, Matt J.; Kuhn, Jeffrey R.
1997STIN...9822262L Altcode:
In this paper, we present a new Stokes polarization observation of a
solar filament using the neutral Helium line at 10830 A. Similar to the
prominence Hanle effect, the polarization of the filament is due to the
resonant scattering and magnetic depolarization of the photospheric
radiation; it differs only in the scattering geometry. Since this
represents one of the first filament polarization observations, we
also present a classical derivation of a set of diagnostic formulae
that relate the filament polarization signals to the vector magnetic
field. We measured the full Stokes profiles (I, Q, U, V) by scanning the
slit of the spectrograph parallel to the axis of a small filament. In
one section of the filament, the polarization signals showed that the
axial component of the magnetic field reverses direction on either side
of the filament axis. This axial field reversal is not predicted by
any of the existing magnetic field models of the filament, nor was it
observed by previous prominence Hanle effect observations. We propose
that a tilted magnetic field loop across the filament axis can explain
the observed axial field reversal. This observation also serves to
demonstrate that measurements of the polarization of the He I 10830 A
radiation from filaments is a useful new tool for the diagnostics of
filament magnetic field structures.
---------------------------------------------------------
Title: Solar Oblateness Measurements by the MDI Instrument on SOHO
Authors: Bush, R. I.; Kuhn, J. R.; Scheick, X.
1997SPD....28.0202B Altcode: 1997BAAS...29Q.893B
The Michelson Doppler Imager instrument on the SOHO spacecraft provides
high precision measurements of the solar limb brightness because of the
absence of atmospheric blurring. This paper will describe the solar
oblateness determined from MDI observations during a roll maneuver
of the SOHO spacecraft performed on 20 March 1997. This maneuver was
requested by the SOI-MDI team in order to obtain precise measurements
of the solar limb and consisted of two 360 degree rolls of the SOHO
spacecraft about the axis pointing to the center of the sun.. By
observing the solar limb during the spacecraft roll, the static
solar shape can be extracted from the distortion caused by the MDI
optics. The primary observable for this activity was the full-disk
computed continuum using 1.96" pixels. The first complete roll was
performed in increments of 30 degrees, and a second roll was performed
in the opposite direction in increments of 90 degrees. The dwell time
at each roll position was nominally 25 minutes, with about 10 minutes
required to roll the spacecraft 30 degrees and precisely determine the
new location. The calibration and analysis of these continuum images
to determine the solar oblateness will be detailed
---------------------------------------------------------
Title: Precision solar astrometry from SoHO/MDI
Authors: Kuhn, J. R.; Bogart, R.; Bush, R.; Sá, L.; Scherrer, P.;
Scheick, X.
1997IAUS..181..103K Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Tidal Streams from the Carina and Draco Dwarf Galaxies
Authors: Smith, H. A.; Kuhn, J. R.; Hawley, S. L.
1997ASPC..127..163S Altcode: 1997pmga.conf..163S
No abstract at ADS
---------------------------------------------------------
Title: Tidal Disruption and Tails from the Carina Dwarf Spheroidal
Galaxy
Authors: Kuhn, J. R.; Smith, Horace A.; Hawley, Suzanne L.
1996ApJ...469L..93K Altcode:
New photometry of regions beyond the classical tidal radius of Carina
exposes a Carina-like stellar distribution that is about 1% of the
central surface density and which extends at least as far as 2 deg (3.5
kpc) from Carina's center. The detections of a spatially extended RR
Lyrae distribution, and a significant Carina-like stellar population at
large central distances confirm predictions of the time-dependent tidal
interaction model and suggest that Carina is not in virial equilibrium.
---------------------------------------------------------
Title: Accounting for the Solar Acoustic and Luminosity Variations
from the Deep Convection Zone
Authors: Kuhn, J. R.; Stein, R. F.
1996ApJ...463L.117K Altcode:
Recent helioseismic observations (Duvall et al.) have demonstrated
how new data analysis techniques can determine local changes in the
acoustic properties beneath the photosphere. The recent results provide
compelling evidence of a latitudinal sound speed variation. Using
results from numerical simulations, we show here how this acoustic
variation has the correct form and amplitude needed to account for
the previously observed solar photometric changes. In this picture,
both the acoustic and irradiance changes may be caused by magnetically
induced entropy fluctuations near the base of the solar convection zone.
---------------------------------------------------------
Title: Infrared lines as probes of solar magnetic
features. XII. Magnetic flux tubes: evidence of convective collapse?
Authors: Solanki, S. K.; Zufferey, D.; Lin, H.; Rueedi, I.; Kuhn, J. R.
1996A&A...310L..33S Altcode:
The magnetic field in the solar photosphere is mainly composed of
magnetic flux tubes. Their formation is not well understood, largely due
to an absence of observational tests of theoretical predictions. Here we
use infrared polarimetric data to test and confirm the prediction that
whereas the field strength of large flux tubes is almost independent
of their magnetic flux, small flux tubes show a strong dependence. Our
work thus strengthens the case for convective collapse as the source of
concentrated solar magnetic fields. We also present the first direct
measurement of the intrinsic field strength of typical intranetwork
elements. A significant fraction of them is in equipartition with the
kinetic energy of convection. Nevertheless, our results suggest that
as far as their internal structure is concerned intranetwork magnetic
features are better described by flux tubes than by turbulent fields.
---------------------------------------------------------
Title: The Precision Solar Photometric Telescopes
Authors: Coulter, R. L.; Kuhn, J. R.; Lin, H.
1996AAS...188.5604C Altcode: 1996BAAS...28..912C
The Precision Solar Photometric Telescopes Program (PSPT) is a
community based activity to develop a network of 2 or 3 small aperture
telescopes for obtaining accurate solar differential photometry. This
effort is centered at the National Solar Observatory (Sunspot, NM)
and is funded by the NSF Atmospheric Radiative Inputs of the Sun to
Earth (RISE) program and the Astronomy Division. The PSPT is a small,
low-scattered-light refracting telescope consisting of a 15-cm doublet
objective, a magnetostrictive tip-tilt mirror for fast guiding,
a .25nm band-pass CaK filter (393.3nm), two continuum filters and
a 2048x2048 CCD camera. The PSPTs will provide full-disk images at
0.1% photometric precision to allow detailed study of the total solar
irradiance variation at various temporal scales. These instruments will
operate as a multiple station network to allow occasional long unbroken
time-series of photometry. The network will produce photometrically
calibrated solar images sufficient for detailed study of photospheric
features such as limb-darkening, faculae, sunspots and plages. RISE/PSPT
will also provide precise measurements of sunspot coordinates, umbral
and penumbral areas, and contrasts. The overall design of the PSPT
will be described. Recent developments, test results, and an outline
of expected data products will be presented.
---------------------------------------------------------
Title: The precision solar photometric telescopes.
Authors: Coulter, R. L.; Kuhn, J. R.; Lin, H.
1996BAAS...28R.911C Altcode:
No abstract at ADS
---------------------------------------------------------
Title: He I 10830 Angstroms Polarimetry of Filament
Authors: Lin, H.; Kuhn, J. R.; Penn, M.
1996AAS...188.8001L Altcode: 1996BAAS...28..956L
Full Stokes parameters (IQUV) were obtained from a filament at the He
I 10830 Angstroms wavelength. These observations provide information
on the vector magnetic field configuration of the filaments, which,
up-to-date, were mostly infered from indirect observations like
the photospheric magnetograms and Hα images. We will present the
instrumentation, as well as the magnetic field configuration of the
filament derived from these data, and discuss their implications to
filament models.
---------------------------------------------------------
Title: Observations of Tidal Disruption of the Carina Dwarf Spheroidal
Galaxy
Authors: Kuhn, J. R.; Smith, H. A.; Hawley, S. L.
1996AAS...188.7705K Altcode: 1996BAAS...28S.954K
New observations of the Carina dwarf spheroidal galaxy have been
obtained at angular distances as far as 2 degrees from its center. Along
the Carina major axis we detect RR Lyraes at Carina's MW distance, but
well beyond its classical tidal radius. Color-magnitude observations
show the existence of a surface density of Carina-population stars which
is a few percent of the central density as far as 3.5kpc away from the
dS center along its major axis. These measurements support the model
of Carina as a tidally disrupting galaxy with no excess dark matter.
---------------------------------------------------------
Title: Earth-Based Observations of the Galileo Probe Entry Site
Authors: Orton, G.; Ortiz, J. L.; Baines, K.; Bjoraker, G.; Carsenty,
U.; Colas, F.; Dayal, A.; Deming, D.; Drossart, P.; Frappa, E.;
Friedson, J.; Goguen, J.; Golisch, W.; Griep, D.; Hernandez,
C.; Hoffmann, W.; Jennings, D.; Kaminski, C.; Kuhn, J.; Laques,
P.; Limaye, S.; Lin, H.; Lecacheux, J.; Martin, T.; McCabe, G.;
Momary, T.; Parker, D.; Puetter, R.; Ressler, M.; Reyes, G.; Sada,
P.; Spencer, J.; Spitale, J.; Stewart, S.; Varsik, J.; Warell, J.;
Wild, W.; Yanamandra-Fisher, P.; Fazio, G.; Hora, J.; Deutsch, L.
1996Sci...272..839O Altcode:
Earth-based observations of Jupiter indicate that the Galileo probe
probably entered Jupiter's atmosphere just inside a region that has
less cloud cover and drier conditions than more than 99 percent of the
rest of the planet. The visual appearance of the clouds at the site was
generally dark at longer wavelengths. The tropospheric and stratospheric
temperature fields have a strong longitudinal wave structure that is
expected to manifest itself in the vertical temperature profile.
---------------------------------------------------------
Title: Sound Speed Variations Near the Photosphere due to Entropy
Perturbations in 3D Numerical Experiments
Authors: Georgobiani, D.; Kuhn, J. R.; Stein, R. F.
1996AAS...188.6910G Altcode: 1996BAAS...28..937G
Results on how the temperature distribution near the solar photosphere
is altered by perturbing the entropy of fluid in the convection zone
several megameters below the surface are presented. Effects on the
emergent intensity and implications for helioseismic observations
are described.
---------------------------------------------------------
Title: Observations of tidal disruption of the Carina dwarf spheroidal
galaxy.
Authors: Kuhn, J. R.; Smith, H. A.; Hawley, S. L.
1996BAAS...28..954K Altcode:
No abstract at ADS
---------------------------------------------------------
Title: The Near-Infrared Coronal Spectrum
Authors: Kuhn, J. R.; Penn, M. J.; Mann, I.
1996ApJ...456L..67K Altcode:
Sensitive measurements of the near-infrared coronal spectrum were
obtained from the 1994 total solar eclipse. A new [S IX] emission line
at 1.25249 +/- 0.00003 mu m has been detected, and a bright, potentially
important diagnostic, [Si X] line at 1.43 mu m has been confirmed. Upper
limits on the intensity of several other predicted IR emission lines
have been established. Also, diffuse He I emission, perhaps geocoronal,
has been observed with a significant heliocentric redshift.
---------------------------------------------------------
Title: Infrared Spectroscopic Observations of Neutral Helium during
the 1994 Eclipse
Authors: Mann, I.; Kuhn, J. R.; Penn, M. J.
1996ASPC..104..345M Altcode: 1996pcdi.conf..345M; 1996IAUCo.150..345M
No abstract at ADS
---------------------------------------------------------
Title: Global changes in the Sun.
Authors: Kuhn, J. R.
1996stsu.conf..231K Altcode:
The following topics were dealt with: some interesting non-acoustic
observables (global observations, solar neutrino variations? another
solar mode?); interpreting velocity and shape data; interpreting
brightness data; experimenting below the photosphere; numerical
experiments, deep questions?
---------------------------------------------------------
Title: Using Scintillation Measurements to Achieve High Spatial
Resolution in Photometric Solar Observations
Authors: Coulter, R.; Kuhn, J. R.; Rimmele, T.
1996SoPh..163....7C Altcode:
The RISE/PSPT (`Radiative Inputs from the Sun to the Earth/Precision
Solar Photometric Telescopes') experiment will attain high differential
photometric precision in full-disk solar images with 1 arc sec
pixels. To achieve this spatial resolution it will be necessary to
use frame selection techniques to minimize the effects of atmospheric
`seeing'. We report here on experiments to use a simple scintillation
monitor as a trigger or `veto' for imaging observations.
---------------------------------------------------------
Title: Preliminary Results of the Analysis of CAII K Spectroheliograms
Authors: Kariyappa, R.; Pap, J. M.; Balasubramaniam, K. S.; Kuhn, J. R.
1995ESASP.376b.429K Altcode: 1995help.confP.429K; 1995soho....2..429K
No abstract at ADS
---------------------------------------------------------
Title: Mapping Prominence Magnetic Fields: New He I 1083 nm Data
Authors: Penn, M.; Kuhn, J.
1995SPD....26..618P Altcode: 1995BAAS...27..965P
No abstract at ADS
---------------------------------------------------------
Title: Imaging Spectropolarimetry of the He i 1083 Nanometer Line
in a Flaring Solar Active Region
Authors: Penn, M. J.; Kuhn, J. R.
1995ApJ...441L..51P Altcode:
Slit spectra, simultaneously measuring left and right circular
polarization of the solar spectrum at 1082.9 +/- 0.4 nm, were taken
using the National Solar Observatory (NSO) Vacuum Tower Telescope
(VTT) at Sacramento Peak with a 128 x 128 pixel HgCdTe IR camera. By
moving the slit the solar active region NOAA 7629 was scanned with a
cadence of 246 s from 1724 to 1902 UT on 1993 December 6. The region
was in the decay phase of a C9.7 flare. Intensity, velocity and
longitudinal magnetic field in both the Si I (photospheric) and He I
(chromospheric) lines are computed from fits to the line profiles
in left and right polarizations. Analysis of these quantities show:
(1) He I line emission in three decaying flare kernels, (2) Zeeman
splitting of the He I emission measuring the longitudinal magnetic
field inside the flare kernels; (3) dark He I active region filaments
avoid strong longitudinal chromospheric magnetic field, and an active
filament (with a transverse speed of 9 km/s) produces fluctuations
in the strength of the longitudinal magnetic fields, and (4) bipolar
moving magnetic features (MMFs) and emerging active region bipoles
(EARBs) are observed at photospheric but not chromospheric heights.
---------------------------------------------------------
Title: The Near Infrared Coronal Spectrum: Results from the 1994
Eclipse
Authors: Kuhn, J.; Penn, M.; Mann, I.
1995SPD....26..609K Altcode: 1995BAAS...27..963K
No abstract at ADS
---------------------------------------------------------
Title: CLEAR : A Concept for a "Coronagraph and Low Emissivity
Astronomical Reflector" for Solar and Nighttime Observations
Authors: Beckers, J. M.; Kuhn, J.; Neidig, D.; Rabin, R.; Rimmele,
T.; Smartt, R. N.
1995SPD....26..722B Altcode: 1995BAAS...27..971B
No abstract at ADS
---------------------------------------------------------
Title: Using Eclipse Observations to Test Scintillation Models
Authors: Georgobiani, D.; Kuhn, J. R.; Beckers, J. M.
1995SoPh..156....1G Altcode:
Near second and third contact during a solar eclipse the spatial
spectrum of the solar illumination changes as the relative power
at high spatial frequencies increases strongly. Since groundlevel
atmospheric scintillation depends on a weighted integral of the image
power spectrum, we can expect to see a measureable time dependence
to solar scintillation during an eclipse. This effect was observed
during an annular solar eclipse and quantitatively compared with a
scintillation model.
---------------------------------------------------------
Title: Solar Variability in Irradiance and Oscillations
Authors: Kuhn, J. R.
1995ESASP.376a.145K Altcode: 1995heli.conf..145K; 1995soho....1..145K
The signature of the solar cycle appears clearly in helioseismic
frequencies and splittings. We have learned that it is the changing
outer superadiabatic region of the Sun that is responsible, but
can we learn about the deeper solar-cycle mechanism from the surface
changes? In particular, how do magnetic fields perturb the global modes,
the solar irradiance, and the luminosity? One-dimensional models do not
capture the physics of this problem. The author shows that progress
will follow from numerical experiments, helioseismic inference, and
accurate solar photometry.
---------------------------------------------------------
Title: Infrared tools for solar astrophysics: What's next?
Authors: Kuhn, Jeffrey R.; Penn, Matthew J.
1995itsa.conf.....K Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Infrared Coronal Magnetic Field Measurements
Authors: Kuhn, J. R.
1995itsa.conf...89K Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Polarimetric IR Array Observations of a Flare
Authors: Penn, M. J.; Kuhn, J. R.
1995itsa.conf..393P Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Ground-based Detection of an Infrared [Si x] Coronal Emission
Line and Improved Wavelengths for the Infrared [Fe xiii] Emission
Lines
Authors: Penn, M. J.; Kuhn, J. R.
1994ApJ...434..807P Altcode:
The wavelength of an infrared (Si X) coronal emission line is measured
to be 1430.084 +/- 0.006 nm with a coronagraph of the National Solar
Observatory at Sacramento Peak (NSOINP). New measurements of the
infrared (Fe XIII) emission lines locate the central wavelengths at
1074.617 +/- 0.005 nm and 1079.783 +/- 0.006 nm. The slit-averaged line
center intensities were 4.5, 27.8, and 5.2 (in units of 10<SUP>-6</SUP>
B(solar)) for the 1430 nm, 1075 nm, and 1080 nm emission lines,
repectively. The spatial distribution of (Si X) emission is correlated
with the coronal electron density as determined from the (Fe XIII)
line ratio. Upper limits are set for coronal emission near 1266 nm
and 1523 nm.
---------------------------------------------------------
Title: Coronal electron density measurements using the near-ir
[Fe XIII] emission lines
Authors: Penn, M. J.; Kuhn, J. R.; Arnaud, J.; Mickey, D. L.; Labonte,
B. J.
1994SSRv...70..185P Altcode:
Observations made during the 1991 total solar eclipse and recent
observations from NSO/Sac Peak are discussed. The ground-based density
measurements will be complimentary to SOHO observations, particularly
SOHO electron density measurements.
---------------------------------------------------------
Title: Removing Instrumental Polarization from Infrared Solar
Polarimetric Observations
Authors: Kuhn, J. R.; Balasubramaniam, K. S.; Kopp, G.; Penn, M. J.;
Dombard, A. J.; Lin, H.
1994SoPh..153..143K Altcode:
Full Stokes polarimetry is obtained using the National Solar
Observatory Vacuum Tower Telescope at Sacramento Peak while observing
the magnetically sensitive infrared FeI line at wavelength of 1.56μ. A
technique is described which makes use of the high magnetic resolution
in this spectral range to remove instrumental polarization from observed
StokesQ, U, andV line profiles.
---------------------------------------------------------
Title: How bright is the [Si X] 1431 nm coronal emission line?
Authors: Penn, M. J.; Kuhn, J. R.
1994SoPh..151...51P Altcode:
Airborne eclipse observations of the [SiX] 1430.5 nm coronal emission
line are reviewed, and new ground-based out-of-eclipse coronagraph
observations obtained at NSO/Sacramento Peak are reported. We find that
the [SiX] 1430.5 nm coronal emission line brightness is less than 8
× 10<SUP>−6</SUP>B⊙ in small active region corona which showed
[FeXIII] 1074.7 nm emission (corrected for sky background) of about
20 × 10<SUP>−6</SUP>B⊙.
---------------------------------------------------------
Title: Diffuse Light in A2670: Smoothly Distributed?
Authors: Scheick, Xania; Kuhn, Jeffrey R.
1994ApJ...423..566S Altcode:
We report R- and V-band observations of the rich cluster of galaxies
A2670. A measurement of the circular component of the diffuse light
or halo of the cD follows a smooth de Vaucouleurs profile out to
230/h kpc. Measurements of the fluctuation per pixel indicate that
the diffuse light is likely to be composed of numerous low-luminosity
objects. Autocorrelations of the residual images allow us to probe
the small-scale fluctuations to a sensitivity of 0.05% of the diffuse
light. A differential luminosity function of the central 160/h kpc
suggests real differences in the luminosity function within the cluster
center from a universal cluster luminosity function. We measure the
V - R color of the cD and cluster galaxies and the color gradient
across the halo. Also, we report results from a search for detecting
evidence of the visible results of dynamical friction, that is, the
wakes associated with galaxies passing through a diffuse medium.
---------------------------------------------------------
Title: Solar Irradiance and Luminosity Variations from Active Regions
Authors: Kuhn, J. R.
1994ASPC...68...43K Altcode: 1994sare.conf...43K
No abstract at ADS
---------------------------------------------------------
Title: Brightness Observations of the Sun
Authors: Kuhn, J. R.
1994svsp.coll..130K Altcode: 1994IAUCo.143P.130K
No abstract at ADS
---------------------------------------------------------
Title: RISE/PSPT as an Experiment to Study Active Region Irradiance
and Luminosity Evolution
Authors: Coulter, Roy L.; Kuhn, J. R.
1994ASPC...68...37C Altcode: 1994sare.conf...37C
No abstract at ADS
---------------------------------------------------------
Title: IR Observations of the K and F Corona During the 1991 Eclipse
Authors: Kuhn, J. R.; Lin, H.; Lamy, P.; Koutchmy, S.; Smartt, R. N.
1994IAUS..154..185K Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Simultaneous IR and Visible Light Measurements of the Solar
Granulation
Authors: Keil, S.; Kuhn, J.; Lin, H.; Reardon, K.
1994IAUS..154..251K Altcode:
No abstract at ADS
---------------------------------------------------------
Title: The Precision Solar Photometric Telescope Project
Authors: Kuhn, J. R.; Coulter, R.
1993AAS...183.0809K Altcode: 1993BAAS...25.1302K
The National Solar Observatory has begun an NSF funded program to obtain
precise differential surface photometry of the sun. This experiment
is directed at understanding the source of the long (yearly) and short
(daily) solar luminosity and irradiance fluctuations. The project will
generate full-disk data over wavelengths from 393 nm to 800 nm with 1
arcsecond/pixel spatial resolution. The relative photometric precision
of the instrument will be 0.1% /pixel with time resolution of about 1
hour. Two stations will allow occasional 24 hour continuous datasets
to be obtained. The current status of the program and scientific focus
of the experiment are reviewed in this paper.
---------------------------------------------------------
Title: Dynamical Friction Wake Candidates in A2029 and Diffuse Light
in Binary Nucleus Clusters
Authors: Scheick, Xania; Kuhn, Jeffrey R.
1993AAS...183.8713S Altcode: 1993BAAS...25R1428S
We present R-band observations of candidate wakes associated with five
galaxies in A2029. The shapes of the wakes are very similar to the
results of Weinberg's 1989 numerical simulations (MNRAS 239 549). We
can use the wakes' characteristics (luminosity, size, curvature,
local diffuse light level) and the parent galaxies' characteristics
(luminosity, radial velocity) to constrain the parent galaxies' mass
and transverse velocity with N-body simulations. We also present
results of an analysis of the diffuse light in two binary nucleus
clusters. Diffuse light has previously been measured in some cD
galaxies to supply up to one third of the total cluster light. With
two clusters having two distinct but interacting central galaxies,
we will address the issue of diffuse light separate from the halos
of these galaxies. The results of this analysis have direct bearing
on cluster evolution models which suggest that cD galaxies and their
large-scale envelopes are formed by mergers.
---------------------------------------------------------
Title: The RISE Precision Solar Photometric Telescope Project
Authors: Kuhn, J. R.; Foukal, P. V.
1993BAAS...25.1184K Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Unbound Dwarf Spheroidal Galaxies and the Mass of the Milky Way
Authors: Kuhn, Jeffrey R.
1993ApJ...409L..13K Altcode:
There are reasonable dynamical arguments to support the claim that
at least some of the Local Group dwarf spheroidal (dSph) galaxies
are not internally bound collections of stars. There are now even
a few observations that bolster this view. This Letter points out
that the lifetimes of these systems may be longer than is commonly
appreciated, and that (as unbound systems) dynamical observations of
the dSph may tell us much more about the mass and dark matter content
of the Milky Way (MW) than they do about the dark matter content of
the dwarf spheroidal.
---------------------------------------------------------
Title: What Causes Cycle-Related Global Solar Changes
Authors: Kuhn, J. R.
1993ASPC...42...27K Altcode: 1993gong.conf...27K
No abstract at ADS
---------------------------------------------------------
Title: Precision Infrared and Visible Solar Photometry - Part One
Authors: Lin, H.; Kuhn, J. R.
1992SoPh..141....1L Altcode:
A precision Solar Photometric Telescope (SPT) was constructed to study
the large-scale thermal structure of the solar photosphere. This
instrument does full-disk, broad-band (10 nm FWHM), two-color (500
and 650 nm) imaging of the solar photosphere. Data obtained by the
SPT reveals network structures correlated with the supergranulation
velocity field, and the CaK network of the chromosphere. Infrared
array photometry extends these measurements to 1.6 and 2.2 micron. The
observed correlation of the network brightness signal with the CaK
network is positive at visible wavelengths. The correlation between
the network at the opacity minimum (1.6 micron) and in the higher
photosphere (2.2 micron) is positive also. The root-mean-square
(r.m.s.) amplitude of the contrast at disk center is (2.34 ± 0.38)
× 10<SUP>-3</SUP>, (1.83 ± 0.51) × 10<SUP>-3</SUP>, (1.02 ± 0.21)
× 10<SUP>-3</SUP>, and (1.11 ± 0.21) × 10<SUP>-3</SUP> for the green,
red, H, and K band, respectively. It is consistent with a brightness
temperature modulation of 2.9 K. The r.m.s. amplitude of the contrast
of active region network shows a large increase toward the limb,
and the quiet region network shows little center-to-limb variation
(CLV). Power-spectrum analysis shows that the bright facular points
in the active regions appear in the form of enhanced network.
---------------------------------------------------------
Title: No Evidence of a Circumsolar Dust Ring from Infrared
Observations of the 1991 Solar Eclipse
Authors: Lamy, P.; Kuhn, J. R.; Lin, H.; Koutchmy, S.; Smartt, R. N.
1992Sci...257.1377L Altcode:
During the past 25 years there have been many attempts to detect a
possible dust ring around the sun, with contradictory results. Before
the 1991 eclipse, infrared eclipse experiments used single-element
detectors to scan the corona along the ecliptic for excess surface
brightness peaks. The availability of relatively large-format infrared
array detectors now provides a considerable observational advantage:
two-dimensional mapping of the brightness and polarization of the corona
with high photometric precision. The 1991 eclipse path included the
high-altitude Mauna Kea Observatory, a further advantage to measure the
corona out to large angular distances from the sun. Results are reported
from an experiment conducted on Mauna Kea with a HgCdTe-array detector
sensitive to wavelengths between 1 and 2.5 micrometers, using broad-band
J, H, and K filters. Although the sky conditions were not ideal, the H-
and K-band surface brightnesses clearly show the inhomogeneous structure
in the K-corona and the elliptical flattening of the F-corona, but no
evidence of a circumsolar, local dust component out to 15 solar radii.
---------------------------------------------------------
Title: Infrared Array Measurements of Sunspot Magnetic Fields
Authors: McPherson, M. R.; Lin, H.; Kuhn, J. R.
1992SoPh..139..255M Altcode:
We have used a 128 × 128 format HgCdTl infrared array with the
Sacramento Peak Observatory Vacuum Telescope (VTT) and Echelle
spectrograph to obtain two-dimensional observations of the true magnetic
field strength in a sunspot. The system we describe retains all of the
spectral information contained in the unpolarized IR Fraunhofer line
profile with time resolution of about a minute (depending on the scan
area and spatial resolution). Unlike previous optical observations
(cf. Adam, 1990), infrared observations readily allow direct field
strength measurements out to the outer edge of the penumbra. Our data
suggest that the magnetic flux density in the outer penumbra is not
well described by an extrapolation of the quadratic polynomial, in
normalized central distance, that describes the umbral field. We measure
a relatively high field strength of 800 G at the penumbra-quiet-Sun
boundary, which is consistent with the `return-flux' model of Osherovich
and Garcia (1989).
---------------------------------------------------------
Title: Infrared Determinations of Magnetic Profiles in Sunspots
Authors: Kopp, G.; Kuhn, J.; Lin, H.; Rabin, D.
1992AAS...180.1202K Altcode: 1992BAAS...24R.747K
We present measurements of a sunspot using unpolarized observations of
the magnetically-sensitive (Lande g=3) Fe I line at lambda =1.5649
microns (6388.6 cm(-1) ). We compare the magnetic field profile
from this fairly symmetric spot with model profiles. Splittings
in this infrared line are nearly a factor of 3 greater than in a
comparable visible line, since Zeeman splitting as a fraction of
linewidth increases linearly with wavelength. The infrared is also
less affected by stray light than the visible, because the intensity
contrast is reduced, decreasing the effects of stray light, and because
instrumental scatter is lower in the infrared. The combination of the
magnetic and stray light advantages of the infrared and the recent
availability of “large” infrared arrays has made possible more
sensitive determinations of the magnetic field profile throughout
sunspots. From observations of several sunspots, we find that the
magnetic field strength, determined in the strong field regime, is not
a smooth function of radius from spot center, and that single radial
parameter models do not accurately describe the observed spots.
---------------------------------------------------------
Title: Nonfacular Solar Luminosity Variations
Authors: Kuhn, J. R.; Libbrecht, K. G.
1991ApJ...381L..35K Altcode:
Solar limb photometry data obtained in 1990 shows a decline in the
active region facular contribution to the solar irradiance from
the previous year - in accord with the maximum in the sunspot cycle
occurring in late 1989. In contrast, the nonfacular and nonsunspot
contribution to the solar flux increased compared to 1989. This third
component of the irradiance variation is consistent with a significant
increase in the total mean solar irradiance from the value observed
near the time of sunspot maximum. Evidently, the irradiance maximum,
like other solar activity indices, exhibits a phase lag with respect
to the solar activity maximum as measured by the sunspot number.
---------------------------------------------------------
Title: Gain calibrating NonUniform Image-Array Data Using Only the
Image Data
Authors: Kuhn, J. R.; Lin, H.; Loranz, D.
1991PASP..103.1097K Altcode:
An algorithm is developed for calibrating the spatial nonuniformity
of image-array (CCD-type) detectors. Like other techniques this
approach uses multiple, spatially displaced images. In circumstances
where high-precision flat fields are not available by other means
(i.e., sky flats) this technique is advantageous as it uses the data
frames for gain calibration even when the array images extended,
nonuniform, sources. Numerical experiments and direct observations
with intrinsically uniform and quite nonuniform detectors show that
this algorithm is useful when data frames are crowded with sources -
circumstance where 'median filtering' flatfielding techniques often
fail. The algorithm described is robust and efficiently uses information
from multiple data frames to determine pixel gain variations, using
visible and IR array observations of extended sources.
---------------------------------------------------------
Title: Short-Term Changes in Solar Oscillation Frequencies and
Solar Activity
Authors: Woodard, M. F.; Kuhn, J. R.; Murray, N.; Libbrecht, K. G.
1991ApJ...373L..81W Altcode:
It is shown that the frequencies of solar rho-mode oscillations
change significantly over periods as short as one month. These changes
correlate significantly with variations in the strength of surface solar
activity as measured by the average, over the sun's visible surface,
of the magnitude of the line-of-sight magnetic field component from
magnetograms. The frequency and mean magnetic variations are found to
obey a linear relationship. It is seen that the mean frequency shift at
any time depends on the history of solar activity over an interval of,
at most, several months prior to the measurement and conclude that the
dominant mechanism of the frequency shift is correlated with surface
magnetic activity.
---------------------------------------------------------
Title: Precision visible and infrared solar photometry.
Authors: Haosheng, Lin; Kuhn, J. R.
1991BAAS...23.1069H Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Diffuse Light in Dense Clusters of Galaxies. I. R-Band
Observations of Abell 2029
Authors: Uson, Juan M.; Boughn, Stephen P.; Kuhn, Jeffrey R.
1991ApJ...369...46U Altcode:
We have developed an observing technique that uses a CCD detector,
multiple overlapping exposures, and a tesselating algorithm that allows
us to do reliable differential photometry over a large (about 0.6^deg^)
field of view to a precision of 2 x 10^-4^ of the night-sky level,
limited only by statistical noise. We have measured the point-spread
function of the telescope-detector combination out to 20' from the
nominal pointing position. We have found that it is necessary to
correct the data for the contamination from the extended halos of
stars brighter than m_R_ = 15.5 in order to measure diffuse light at
levels below μ ~ 26, or about 1% of the average night-sky level. We
present R-band observations of the very dense cluster of galaxies Abell
2029. We detect an elliptical component of diffuse light-extended halo
of the cD galaxy-with constant eccentricity of 0.9 that follows a de
Vaucouleurs profile out to a distance of 425h^1^ kpc [measured as d =
(r_min_ r_max_)^1/2^]. The integrated luminosity of the cD galaxy with
this halo is 5 x 10^11^h^-2^ L_sun_ (R band). The ratio of the diffuse
light to the total cluster light in the elliptical annulus between
d = 250h^-1^ kpc and d = 425h^-1^ kpc is 0.10 +/- 0.005, where the
uncertainty comes mainly from the estimate of the contribution of the
galaxies. We place an upper limit of 5% to the ratio of diffuse light
to total cluster light in the elliptical annulus between d = 425h^-1^
kpc and d = 850h^-1^ kpc.
---------------------------------------------------------
Title: Precision Visible and Infrared Solar Photometry
Authors: Lin, H.; Kuhn, J. R.
1991BAAS...23.1069L Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Inferring solar structure variations from photometric and
helioseismic observations
Authors: Kuhn, J. R.
1991AdSpR..11d.171K Altcode: 1991AdSpR..11..171K
Present large scale photometric and helioseismic data may be related
to spatial and temporal deviations from an otherwise static, spherical
solar convection zone (SCZ). New space experiments combine precise
photometric, helioseismic, and magnetic observational capabilities
(like SOHO and MDI) and will provide data needed to understand the
interaction of magnetic fields and global scale circulation in the
SCZ. Even simple physical arguments make it clear that the anticipated
accuracy of these new experiments virtually guarantees new constraints
on models of the SCZ.
---------------------------------------------------------
Title: The Variability of the Solar Diameter
Authors: Ribes, E.; Beardsley, B.; Brown, T. M.; Delache, Ph.; Laclare,
F.; Kuhn, J. R.; Leister, N. V.
1991suti.conf...59R Altcode:
It is argued here that most of the variation in observations of
the solar radius of over three centuries measure properties of the
sun's limb darkening function and are affected by many sources of
degradation of the solar image. They do not directly measure a true
solar radius. From a long series of visual observations made by a
single observer as well as recent photoelectric observations, evidence
is found for periodicities in the apparent radius that occur in both
modern and historical records. The magnitude of the observed variations
is quite different in visual and photoelectric observations, suggesting
that the process responsible for the periodicities is either one that
modifies the solar limb darkening function or one that causes systematic
variations in image blurring by the earth's atmosphere. A connection
between solar magnetic activity an apparent radius seems likely, with
evidence for such a relation dating back as fast as the Maunder minimum.
---------------------------------------------------------
Title: The Central Galaxy in Abell 2029: An Old Supergiant
Authors: Uson, Juan M.; Boughn, Stephen P.; Kuhn, Jeffrey R.
1990Sci...250..539U Altcode:
A mosaic of images shows the extended structure of the cD galaxy that
resides at the center of the rich cluster of galaxies Abell 2029. After
correcting for the scattered light of nearby stars and galaxies, the
faint halo of this giant can be traced out to a distance of more than
1 megaparsec, making it one of the largest and most luminous galaxies
known. The smoothness of this halo suggests that it was formed early
in the history of the cluster.
---------------------------------------------------------
Title: Consistency in Trends in Helioseismic Data and Photospheric
Temperature Data through the Solar Cycle
Authors: Goode, Philip R.; Kuhn, J. R.
1990ApJ...356..310G Altcode:
Inversion confirms the apparent correlation between trends in the
helioseismic data and the photospheric temperature data. Although the
helioseismic data are noisy, the radial dependence in the results
appear to support a model of a cold or hot thermal shadow arising
from, perhaps, the dynamo magnetic field seated near the base of the
convection zone.
---------------------------------------------------------
Title: Dwarf Spheroidal Galaxies and the Outer Milky Way Potential
Authors: Kuhn, J. R.; Hipple, R.
1990BAAS...22..867K Altcode:
No abstract at ADS
---------------------------------------------------------
Title: CCD Observation of Diffuse Light in the Rich Cluster A:2029
Authors: Boughn, S. P.; Kuhn, J. R.; Uson, J. M.
1990IAUS..139..357B Altcode:
By mosaicking many CCD frames together, a large-scale (1/2 deg)
R-band map of the cD cluster Abell 2029 has been constructed. The
map was flat from one edge to the other to about 0.05 percent of
the night sky, which corresponds to v(R) 30 mag sq arcsec. A novel
technique involving the pixel distribution function, was used to
measure diffuse light in the cluster out to 450 arcsec (500/h Kpc)
along the minor axis of the cluster. In the elliptical region from
minor radius 100 arcsec to minor radius 300 arcsec, the diffuse light
corresponds to roughly 8 percent of the total cluster light. Data in
other optical bands and on other clusters are in the process of being
reduced. The applicability of the above technique to measurements of
the fluctuations in the extragalactic background light is discussed.
---------------------------------------------------------
Title: Measuring Solar Structure Variations from Helioseismic and
Photometric Observations
Authors: Kuhn, J. R.
1990LNP...367..157K Altcode: 1990psss.conf..157K
There has been some discussion at this meeting of small changes
in frequencies and frequency splittings observed during the solar
cycle. Previous observations of frequency changes at the level of 10-4
have been convincingly confirmed by several observations presented at
this meeting (Jefferies et al. 1990; Libbrecht and Woodard 1990; Pallé
et al. 1990). It has been noted that solar photometric (differential and
absolute) observations are of comparable accuracy and show similar solar
cycle variations. I will summarize here how the latest photometric and
helioseismic data may be accounted for by changes in the the convection
zone during a solar cycle. Some of these data and this model have been
further described elsewhere (Kuhn 1989; Goode and Kuhn 1990).
---------------------------------------------------------
Title: An imaging, tunable magneto-optical filter
Authors: Lin, H.; Kuhn, J. R.
1989SoPh..122..365L Altcode:
The Imaging, Tunable Magneto-Optical Filter (ITMOF) is a one-
or two-cell magnetic birefringence filter designed to measure the
Doppler shift of the solar potassium line (770 nm) with respect to a
laboratory standard. Two gas vapor cells contain isotopically refined
potassium and operate at temperature near 393 K. Hot cell windows
are employed in a carefully controlled thermal environment to limit
spurious birefringence in the pyrex cell and prevent condensation in the
light path. Electromagnets provide a variable strength and direction
longitudinal magnetic field of up to 5000 G on each cell. There is no
rotating quarter-wave plate or other moving parts. The final image is
detected with a CCD camera system.
---------------------------------------------------------
Title: Dwarf Spheroidal Galaxies and Resonant Orbital Coupling
Authors: Kuhn, J. R.; Miller, R. H.
1989ApJ...341L..41K Altcode:
The structural properties of the dwarf spheroidal satellite galaxies
of the Milky Way may be strongly affected by their time-dependent
interactions with the "tidal" field of the Milky Way. A low Q resonance
of the tidal driving force with collective oscillation modes of the
dwarf system can produce many of the observed properties of the Local
Group dwarf spheroidal galaxies, including large velocity dispersions
that would normally be interpreted as indicating large dynamical masses.
---------------------------------------------------------
Title: Helioseismic Observations of the Solar Cycle
Authors: Kuhn, J. R.
1989ApJ...339L..45K Altcode:
Satellite and limb photometry observations of the sun yield a consistent
picture of a changing effective temperature distribution in the
photosphere. Those observations are used to show that a large change
in helioseismic splitting coefficients and mode centroid frequencies
should be observed in helioseismic data obtained in 1988.
---------------------------------------------------------
Title: Calculating the Internal Solar Asphericity from Frequency
Splitting Measurements
Authors: Kuhn, J. R.
1989SoPh..123....1K Altcode:
Considerable effort and progress has been made in measuring the internal
solar rotation from observations of the odd-order helioseismological
splitting coefficients (cf. Brown and Morrow, 1987, and references
therein). Less progress has been made in using the even coefficients
to measure the internal solar structure (cf. Duvall, Harvey, and
Pomerantz, 1986; Gough and Taylor, 1984; Dziembowski and Goode, 1984,
and references). Yet, small deviations from spherical symmetry in the
internal solar structure may be inferred from the helioseismological
splitting observations. Spherical-harmonic decomposition and first-order
perturbation theory provide a convenient formalism for describing the
distortion. Here I describe the formalism and a new, computationally
efficient, method for calculating the kernel functions that are needed
to invert the splitting data to obtain the structural asphericity.
---------------------------------------------------------
Title: Resonant Orbital Tidal Interactions: Dwarf Spheroidal
Morphology and Dynamics
Authors: Kuhn, J. R.; Miller, R. H.
1989BAAS...21..767K Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Convection and Waves
Authors: Stein, R. F.; Nordlund, Å.; Kuhn, J. R.
1989ASIC..263..381S Altcode: 1989ssg..conf..381S
No abstract at ADS
---------------------------------------------------------
Title: CCD Observations of Variable Stars in Globular Clusters
Authors: Smith, H. A.; Kuhn, J. R.; Curtis, J.
1989upsf.conf..285S Altcode: 1989IAUCo.111..285S
No abstract at ADS
---------------------------------------------------------
Title: Convection and p-mode oscillations.
Authors: Stein, R. F.; Nordlund, A.; Kuhn, J. R.
1988ESASP.286..529S Altcode: 1988ssls.rept..529S
The authors have simulated the upper 2.5 Mm of the solar convection
zone using a three-dimensional, compressible, hydrodynamic computer
code. Preliminary results show that convection excites p-mode
oscillations. The frequencies of the modes in the numerical simulation
agree well with the eigenfrequencies of our computational box calculated
for the time averaged mean atmosphere. The agreement is excellent at low
frequencies, and diverges at higher frequencies in a manner similar to
the difference between observed and theoretical frequencies for the sun.
---------------------------------------------------------
Title: Radial and temporal structure of the internal solar
asphericity.
Authors: Kuhn, J. R.
1988ESASP.286...87K Altcode: 1988ssls.rept...87K
There are large systematic differences between the measured
even-order splitting coefficients obtained from different helioseismic
observations. These data were obtained by several groups, starting
about 6 years ago, and used different observing techniques (e.g. Doppler
vs. Intensity full disk solar observations) to derive the m-dependence
of mode frequencies. Given the wide variation between the observation
techniques it may not be surprising that the results differ - yet, the
author argued that the variation between datasets may be physically
significant and directly related to solar cycle variations in the
aspheric structure of the sun. This asphericity is not confined to the
photosphere and is related to the solar cycle luminosity variations
measured by ACRIM and the solar limb brightness observations.
---------------------------------------------------------
Title: The Surface Temperature of the Sun and Changes in the Solar
Constant
Authors: Kuhn, J. R.; Libbrecht, K. G.; Dicke, R. H.
1988Sci...242..908K Altcode:
The solar distortion telescope has been used to measure the limb shape
and latitude dependence of the limb brightness during the summer months
for a 5-year period--a time base sufficient to detect solar cycle
trends in the data. Comparison of these observations with spaceborne
measurements of the solar constant suggests that a significant part
of the solar cycle variation in irradiance is a result of temporal
changes in the latitude-dependent surface temperature of the sun.
---------------------------------------------------------
Title: Helioseismological Splitting Measurements and the Nonspherical
Solar Temperature Structure
Authors: Kuhn, J. R.
1988ApJ...331L.131K Altcode:
Helioseismological observations continue to yield new information on
the structure of the solar interior. Measurements of the splitting of
the frequency degeneracy of modes of a given spherical harmonic order
already provide a measure of the internal solar radial differential
rotation. It is shown here how the even-order terms may be related to
an internal nonspherical solar temperature structure. In addition, the
apparent inconsistency of the different splitting measurements may be
understood from the time dependence observed in the limb observations,
which, as shown here, imply a corresponding temporal variation in the
splitting data.
---------------------------------------------------------
Title: Non-Newtonian Forces and the Observed Solar Oscillation
Spectrum
Authors: Kuhn, J. R.
1988IAUS..123..119K Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Solar 5-MIN Oscillation Amplitude Anisotropy and Doppler
Velocity Systematics
Authors: Kuhn, J. R.; O'Neill, C. M.; Gilliam, L. B.
1988IAUS..123...63K Altcode:
Several measurements of 5-min velocity amplitudes have yielded confusing
and conflicting information on the l and m dependence of the modal
excitation (Kuhn and O'hanlon, 1983 - henceforth KO; Deubner, 1985;
and Hill et al. 1985). The authors have obtained considerably more data
than was described in KO using similar observing techniques. Additional
analysis has illuminated a systematic effect related to the finite
spatial resolution, and line asymmetry of the data that can lead to
errors in inferred velocity amplitudes.
---------------------------------------------------------
Title: Measuring the Solar Limb Brightness
Authors: Kuhn, J.
1988srov.proc..217K Altcode:
No abstract at ADS
---------------------------------------------------------
Title: An Imaging Tunable Magneto-Optical Filter for Stable Solar
Doppler Observations
Authors: Lin, H. -S.; Kuhn, J. R.
1987BAAS...19.1097L Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Cluster Diffuse Light Measurements
Authors: Kuhn, J. R.; Boughn, S. P.; Uson, J. M.
1987BAAS...19.1105K Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Observations of a Solar Latitude-dependent Limb Brightness
Variation: Erratum
Authors: Kuhn, J. R.; Libbrecht, K. G.; Dicke, R. H.
1987ApJ...319.1010K Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Is the Solar Oblateness Variable? Measurements of 1985
Authors: Dicke, R. H.; Kuhn, J. R.; Libbrecht, K. G.
1987ApJ...318..451D Altcode:
The solar oblateness measured in 1985 is Δr =
r<SUB>eq</SUB>-r<SUB>p</SUB> = 14.6±2.2 arc ms, where the error is
only a formal standard deviation assuming normally distributed and
uncorrelated errors. The above result is significantly greater than
the 1984 value which, in turn, is significantly less than the 1983
and 1966 values. The differences may be physically significant and are
consistent with the hypothesis that the oblateness oscillates with the
11.14 yr period of the solar cycle. The data at present only weakly
support this hypothesis.
---------------------------------------------------------
Title: Evidence of global circulation currents from solar-limb
temperature variations
Authors: Kuhn, J. R.; Libbrecht, K. G.; Dicke, R. H.
1987Natur.328..326K Altcode:
The temperature distribution in a turbulent rotating photosphere is
non-spherical. Dimensional arguments for the Sun suggest that such a
temperature modulation may have an amplitude ΔT~ Tv<SUP>2</SUP>/Φ~0.1
K, where T is an average temperature (5,700 K) and v<SUP>2</SUP>/Φ
is the ratio of the rotational kinetic and potential energy density of
the photosphere. Detailed calculations<SUP>1-3</SUP> generally support
this expectation. Here we report new observations that should help to
understand the solar global dynamics problem. From about 1,400 h of
solar-limb data obtained during the summers of 1983-85 we find that
the solar-limb temperature variation is not spherically symmetric and
is ~1 K. Our results also indicate that the limb temperature departs
from its expected l = 2 spatial harmonic form and has, at most, a weak
dependence on solar cycle.
---------------------------------------------------------
Title: Solar distortion measurements
Authors: Dicke, R. H.; Kuhn, J. R.
1987prnc.rept.....D Altcode:
Highly accurate solar limb temperature and shape observations were
obtained from Mt Wilson using a highly specialized telescope. The solar
oblateness appears to fluctuate on a time scale of years. A latitude
dependent solar limb temperature variation exists with a temperature
amplitude of about 0.6k. This temperature variation is independent
of the solar cycle. Oblateness of the Sun in 1983 and Relativity;
On the Facular Contrast Near the Solar Limb; Brightness Variation;
Another Reason to Search for Solar g-Modes and New Limits from Solar
Ellipticity Measurements; Solar Ellipticity Fluctuations Yield No
Evidence of g-Modes; The Variable Oblateness of the Sun: Measurements
of 1984; Is the Solar Oblateness Variable? Measurements of 1985;
More Evidence for a Solar Latitude Dependent Limb Temperature Variation.
---------------------------------------------------------
Title: Non-Newtonian Forces and the Invisible Mass Problem
Authors: Kuhn, J. R.; Kruglyak, L.
1987ApJ...313....1K Altcode:
Experimental or observational tests of the 1/r-squared gravitational
force law are weak or nonexistent at length scales beyond the solar
system. This is because at long distances all astrophysical estimates
of mass density based on dynamics give larger values than corresponding
measurements based on observed luminosity and local mass-to-luminosity
ratios. The discrepancy generally increases with increasing distance,
from galactic lengths to at least cluster scales near 10 Mpc, and is
usually interpreted as evidence for missing mass. From an empirical
perspective that does not recognize the existence of dark matter unless
it is nondynamically confirmed, it could be concluded that there are
no significant constraints on possible spatial variations in Newton's
constant at large distances. The implications of a simple force law
correction to Newtonian gravity from planetary to cosmological distances
are discussed.
---------------------------------------------------------
Title: Limits on a stochastic gravitational wave background from
observations of Earth normal modes.
Authors: Boughn, S. P.; Kuhn, J. R.
1987txra.symp...31B Altcode:
No abstract at ADS
---------------------------------------------------------
Title: More Evidence for a Solar Latitude Dependent Limb Temperature
Variation
Authors: Kuhn, J. R.
1987ASSL..137...51K Altcode: 1987isav.symp...51K
A preliminary analysis of solar limb data obtained during 1983, 1984
and 1985 supports the observation that the sun has a 0.6°K effective
limb temperature variation with a temperature minimum near 50° north
and south latitude and no detectible solar cycle time scale variability.
---------------------------------------------------------
Title: The Variable Oblateness of the Sun: Measurements of 1984
Authors: Dicke, R. H.; Kuhn, J. R.; Libbrecht, K. G.
1986ApJ...311.1025D Altcode:
The solar oblateness measured in 1984 appears to be significantly less
than the 1983 value. This is in turn substantially less than the 1966
value. The observations of 1983 and 1984 were made with a modified and
improved version of the Princeton Solar Distortion Telescope used in
1966. Its design is discussed. The sources of error and the analysis
technique are discussed. The observed changes in oblateness of the
sun are believed to be real and significant.
---------------------------------------------------------
Title: A Search for Extragalactic Background Light Using the Dark
Cloud L134
Authors: Boughn, S. P.; Kuhn, J. R.
1986ApJ...309...33B Altcode:
CCD surface photometry at 0.65 micron and single-aperture photometry
at 2.2 microns on the dark molecular cloud, L134, and on nearby blank
sky, were carried out at levels of 0.001 and less than 0.0001 of the
brightness of the night sky, respectively. Presumably because of the
reflected Galactic light, the cloud appeared bright compared to the
reference sky at both these wavelengths. Relative to blank fields, the
darkest positions on the cloud had intensities of 1 x 10 to the -5th
erg s/sq cm/s/sr at 0.65 micron and 4 x 10 to the -5th ergs/sq cm/s/sr
at 2.2 microns. Since the magnitude of the reflected light is unknown,
one cannot deduce the level of the extragalactic background light (EBL);
however, either the EBL is on the order of or smaller than these values,
or the reflected light and the EBL fortuitously cancel.
---------------------------------------------------------
Title: Alternatives to a Galactic Dark Matter Distribution
Authors: Kuhn, J. R.
1986BAAS...18.1024K Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Solar ellipticity fluctuations yield no evidence of g-modes
Authors: Kuhn, J. R.; Libbrecht, K. G.; Dicke, R. H.
1986Natur.319..128K Altcode:
Although there have been several claims for the detection of solar
g-modes with periods between 2 and 10 hours<SUP>1-3</SUP> and
although the present sensitivity of the Princeton Solar Distortion
Telescope should allow these low frequency modes to be observed, solar
oblateness data from the summers of 1983 and 1984 show no evidence of
such oscillations with periods between 1 and 5 hours. In about 250
days (nearly 1,000 hours) of observations, we find no evidence for
significant spectral power associated with g-modes. In particular,
there is no evidence of a 160.01-min period solar oscillation.
---------------------------------------------------------
Title: Another reason to search for solar g-modes and new limits
from solar ellipticity measurements.
Authors: Kuhn, J. R.
1986ASIC..169...63K Altcode: 1986ssds.proc...63K
Observations of solar g-modes will teach us some gravitational
physics. The present sensitivity of the Princeton Solar Distortion
Telescope and other recent claims of solar g-modes suggest that these
low frequency modes should be observable in shape measurements. From
about 250 days and nearly 1000 hours of observations the author finds
no evidence for significant spectral power that can be associated with
g-modes and no sign of the elusive 160.01 min period solar oscillation.
---------------------------------------------------------
Title: Dark matter in clusters?
Authors: Kuhn, J. R.
1986NRAOW..16..291K Altcode:
The missing dynamical mass in clusters is still missing (i.e. undetected
by nondynamical means). The author shows how a simple relationship
accounts for the required dynamical mass in terms of one parameter
and only the visible mass distribution. The simplicity of the model
argues for its physical interest and the single parametrization
may be a clue to the form of the dark matter (henceforth denoted DM)
constituents. It is also interesting that the effect of DM in clusters
is in detail formally equivalent to adding another long range force that
couples to visible mass - although the model provides, equivalently,
a statement about the distribution of the DM. It is formulated below in
terms of only the visible mass density of a cluster and an additional
"effective" long range interaction.
---------------------------------------------------------
Title: On the facular contrast near the solar limb
Authors: Libbrecht, K. G.; Kuhn, J. R.
1985ApJ...299.1047L Altcode:
Libbrecht and Kuln (1984) have conducted measurements of the continuum
contrast of solar faculae in wavelength bands centered at 800 and
525 nm. Some of the obtained results did not agree with observations
reported by Chapman and Klabunde (1982). The present paper has the
objective to provide new data, taking into account a demonstration of
a procedure for obtaining the facular contrast near the solar limb on
the basis of a simple analysis. The findings confirm the results of
Libbrecht and Kuln that the contrast in the region near the extreme
solar limb decreases with decreasing distance to the limb. Attention
is given to exposed limbs and flux ratios for three occulting disks,
seasonal average normalized flux profiles Delta F/I for the three
disks in two colors, and excess facular signal Delta F/I plotted for
various disks using 1984 data.
---------------------------------------------------------
Title: Oblateness of the Sun in 1983 and relativity
Authors: Dicke, R. H.; Kuhn, J. R.; Libbrecht, K. G.
1985Natur.316..687D Altcode:
Measurements of the solar oblateness obtained during 1983 from Mount
Wilson, California, yield a value with an upper bound only half of
that observed in 1966. This difference may support the conjecture
that the solar quadrupole moment slowly oscillates. A knowledge of
the character of such an oscillation, if it occurs, would be needed
to test Einstein's relativity theory using Mercury's orbital motion.
---------------------------------------------------------
Title: Observations of a Solar Latitude-dependent Limb Brightness
Variation
Authors: Kuhn, J. R.; Libbrecht, K. G.; Dicke, R. H.
1985ApJ...290..758K Altcode:
A small latitude-dependent photospheric excess brightness variation has
been observed from 131 days of data obtained with the Princeton Solar
Distortion Telescope. Using an analytic model to separate the influence
of faculae from the brightness signal, a temperature difference of 0.6 +
or - 0.1 K between the poles and the regions at + or - 53 solar latitude
was obtained for the summer of 1983, a temperature difference of 0.6 +
or - 0.1 K between the poles and the regions at + or - 53 deg solar
latitude was obtained for the summer of 1983, with the polar regions
being hotter.
---------------------------------------------------------
Title: Spectral information from gapped data: a comparison of
techniques.
Authors: Kuhn, J. R.
1984sses.nasa..293K Altcode: 1984sss..conf..293K
The fast Fourier transformations (FFT) is used to estimate power spectra
of continuous signals evenly sampled on discrete domains. The problem
of finding power spectra on unevenly sampled domains, in particular
a regularly spaced domain with gaps is discussed. The analysis of the
ACRIM solar bolometric intensity data, obtained with a 3/5 on and 2/5
off duty cycle of approximately 100 minutes, would benefit from the
techniques. The comparative effectiveness of three different analysis
techniques applied to synthetic data generated on gapped domain is
reported.
---------------------------------------------------------
Title: Limits on a stochastic gravitational wave background from
observations of terrestrial and solar oscillations
Authors: Boughn, S. P.; Kuhn, J. R.
1984ApJ...286..387B Altcode:
Realistic models of the Earth and Sun are used to calculate their
respective responses to a homogeneous, isotropic background of
gravitational radiation. Solar velocity data constrain the energy
density of such a background at a frequency of 4 x 10<SUP>-4</SUP> Hz to
be less than 10<SUP>2,</SUP> times the closure density of the universe,
as does Earth seismic data at frequencies of 2 x 10<SUP>-3</SUP> Hz
and 2 x 10<SUP>-2</SUP> Hz. With improved data soon to be available it
is likely that both of these limits will be lowered to below closure
density. Errors in previous analyses of the Earth are pointed out.
---------------------------------------------------------
Title: Anisotropy and amplitude structure of low-l 5-min solar
oscillations
Authors: Kuhn, J. R.
1984MmSAI..55...69K Altcode:
Line-center Doppler-shift data has been obtained from CCD-spectrograph
observations. The 5-hour time series yields useful information
at spatial wavelengths near one solar radius along both the solar
north-south and east-west orientations. At these wavelengths the
5-min-oscillation velocity field is not isotropic and not well
described by modes of uniform excitation. The velocity power density
per spherical harmonic increases with decreasing l to 1100 sq cm/sq
sec per 350-microhertz angular-frequency bandwidth at l = 4. It is
interesting that the calculated low-l dependence in the growth rate
of p-modes due to the kappa mechanism shows a similar behavior.
---------------------------------------------------------
Title: Observations of a Solar Latitude Dependent Photospheric
Brightness Variation
Authors: Kuhn, J. R.; Libbrecht, K. G.; Dicke, R. H.
1984BAAS...16..451K Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Limits on a Stochastic Gravitational Wave Background from
Observations of Terrestrial &Solar Oscillations
Authors: Boughn, S. P.; Kuhn, J. R.
1984BAAS...16..452B Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Random Walk Statistics Applied to Large Scale Galaxy Maps
Authors: Wolpert, D. H.; Kuhn, J. R.
1984BAAS...16..488W Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Gravitational wave excitation of the 160-min solar oscillation?
Authors: Kuhn, J. R.; Boughn, S. P.
1984Natur.308..164K Altcode:
Recent γ-ray observations<SUP>1</SUP> of the, apparently, nearby
source Geminga suggest the possibility that it is a close binary pair
of compact stellar objects orbiting with a period of 160 or perhaps
320 min (Delache<SUP>1</SUP> speculates that a 160-min periodicity
in the γ-ray flux might still be a signature of a 320-min orbital
period). The coincidence of this period with the observed 160-min
periodicity in the full disk solar velocity data has led G. Isaak
(personal communication) and others to speculate that the gravitational
waves emitted by the binary pair are exciting a normal mode of the
Sun. Solar velocity data<SUP>2-4</SUP> confirm the existence of an
approximately 50 cm s<SUP>-1</SUP> oscillation in integrated Doppler
shift observations that has been phase coherent for ~9 yr. We report
here a calculation of the solar cross-section for gravitational wave
excitation and discuss why such a mechanism is an extremely unlikely
explanation of the observed solar oscillation.
---------------------------------------------------------
Title: A new measurement of the facular contrast near the solar limb
Authors: Libbrecht, K. G.; Kuhn, J. R.
1984ApJ...277..889L Altcode:
Photometer measurements of solar faculae taken at 525 nm and 800 nm over
a five-month period in the summer of 1982 are presented. They reveal a
contrast function which decreases with decreasing mu near the extreme
limb, in striking disagreement with the result of Chapman and Klabunde
(1982). It is shown that systematic errors in the Chapman-Klabunde
data analysis could account for the discrepancy. The instrument and
observing program of this study and the procedure used to identify
faculae near the limb are described. The effectiveness of different
analysis programs for determining the contrast function from photometer
data is discussed and the analysis procedure used on the presented
data is described in detail. The results are in good agreement with
the facular model of Spruit (1976).
---------------------------------------------------------
Title: Center-to-Limb Variation of the Convective Line Shift
Authors: Kuhn, J. R.
1984ssdp.conf..381K Altcode:
Full disk Fraunhofer line core shifts have been analysed for evidence
of a latitude dependence to the residual convective blue shift,
and temporal variability greater than expected from the low-l
5 min oscillations. The author finds no evidence for a latitude
dependence to the mean convective shift at the two sigma level of
105 m s<SUP>-1</SUP>. The global symmetric line shift profile shows
temporal variability in the 5-min band which is larger than expected
based on estimates of the 5-min mode amplitudes.
---------------------------------------------------------
Title: Using Solar Oscillations to Search for Gravitational Radiation
Authors: Kuhn, J. R.; Boughn, S. P.
1984LIACo..25..224K Altcode: 1984tpss.conf..224K; 1984trss.conf..224K
No abstract at ADS
---------------------------------------------------------
Title: Low-l 5-min oscillation observations.
Authors: Kuhn, J. R.; Ohanlon, M.
1983SoPh...87..207K Altcode: 1983SoPh...87..207O
Medium resolution CCD-spectrograph observations have been obtained
that are suitable for studying long spatial wavelength 5-min
oscillations. We find evidence that at wavelengths of order one solar
radius the oscillation field is not isotropic. It is also not well
described by modes of uniform excitation. The velocity power density per
spherical harmonic increases with decreasing l to 1.1 × 10<SUP>3</SUP>
cm<SUP>2</SUP> s<SUP>−2</SUP> per 3.5 × 10<SUP>−4</SUP> Hz angular
frequency bandwidth at l = 4. These results are inconsistent with the
data of Fossat and Ricort (1975) as analyzed by Christensen-Dalsgaard
and Gough (1982), who found a substantially constant modal amplitude
at intermediate l values. It is interesting that other calculations
have seen a similar dependence at small l in the growth rate of p-modes
due to the κ-mechanism.
---------------------------------------------------------
Title: Facular influences on the apparent solar shape
Authors: Dicke, R. H.; Kuhn, J. R.; Libbrecht, K. G.
1983Natur.304..326D Altcode:
Schatten and Sofia<SUP>1</SUP> have recently reconsidered the question
of whether the 1966 solar ellipticity measurements<SUP>2</SUP> were
seriously contaminated by excess brightness of faculae near the solar
limb<SUP>3-7</SUP>. They considered several different functions for
the variations of the facular contrast with position relative to the
solar limb. With their own facular contrast function, Schatten and Sofia
obtain only a small contribution of faculae to the 1966 apparent solar
ellipticity, but with the Chapman function they obtain a substantial
contribution. New observations of faculae during the summer of 1982
and a novel analytical technique determine a facular contrast which is
constant or decreasing towards the limb, consistent with the Schatten
and Sophia function but inconsistent with Chapman's function. We show
here that the statistical analysis of the 1966 data<SUP>8</SUP> supports
this result. We disagree with the earlier conclusion<SUP>1</SUP>,
that with an acceptable facular contrast function one can obtain “an
acceptable fit to the oblateness measurements” as a purely facular
effect. For 20-30% of the observational days in 1966 only a few small,
weak facular patches were present at the limb, but the ellipticity
signal was present and it was not reduced in magnitude for those days.
---------------------------------------------------------
Title: Low-1 5-min Oscillation Observations
Authors: Kuhn, J. R.
1983BAAS...15Q.705K Altcode:
No abstract at ADS
---------------------------------------------------------
Title: A New Measurement of the Facular Contrast Near the Solar Limb
Authors: Libbrecht, K. G.; Kuhn, J. R.
1983BAAS...15..717L Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Observations of global-scale photospheric Fraunhofer line
shifts
Authors: Kuhn, J. R.
1983ApJ...264..689K Altcode:
Transform techniques have been applied to a 1 yr sequence of solar
photospheric Fraunhofer line shift data. In agreement with earlier
studies, no evidence is found of large-scale structure in mean spatial
power spectra near the level of 12 m/s. It is argued that such spectra
are easily dominated by random supergranule noise, and that these
data may even be used to estimate supergranule characteristics. By
considering a rotation signal in the temporal transformed data,
statistical evidence (at the 3 sigma level) is found of a large-scale,
long-lived, photospheric line shift field. A simple model suggests
spatial scales of 100,000-1,000,000 km, with lifetimes of at least
3 days and line shifts corresponding to velocity amplitudes near
2 m/s. While the interpretation of the residual line shift is not
unambiguous, it is suggested that this is the Doppler velocity signature
of large-scale convective cells.
---------------------------------------------------------
Title: Filamentary structure in the Shane-Wirtanen galaxy
distribution.
Authors: Kuhn, J. R.; Uson, J. M.
1982ApJ...263L..47K Altcode:
The paper considers a statistic that is sensitive to differences in the
galaxy distribution of the Shane-Wirtanen catalog and similar random
catalogs with the same low-order galaxy autocorrelation functions. It
has been indicated by numerical experiments that this statistic is a
measure of the filamentary structure in these catalogs. The present
results show that there is significantly more filamentary structure in
the Shane-Wirtanen galaxy distribution than in model catalogs without
added chainlike structure.
---------------------------------------------------------
Title: Does the Shane-Wirtanen Galaxy Distribution have Filamentary
Structure?
Authors: Kuhn, J. R.; Uson, J. M.
1982BAAS...14..631K Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Recovering spectral information from unevenly sampled data -
Two machine-efficient solutions
Authors: Kuhn, J. R.
1982AJ.....87..196K Altcode:
Astronomical data are often unevenly sampled. The problem of recovering
a discrete Fourier transform is discussed, and two procedures for
recovering an approximation to the transform are presented. Numerical
examples suggest that the approach may be useful for many types of
sample domains.
---------------------------------------------------------
Title: Possible radio flaring activity on a late-type giant star,
alf Cet.
Authors: Boice, D. C.; Kuhn, J. R.; Robinson, R. D.; Worden, S. P.
1981ApJ...245L..71B Altcode:
A search is made for radio flare events on 15 late-type stars using the
Arecibo radio telescope at 430 MHz. About 50 hr of interference-free
data are obtained and one impulsive event is detected for the M2
III star Alpha Cet. The observed radio event is consistent with the
hypothesis that it originated in a solar-flare-type disturbance in
the stellar atmosphere.
---------------------------------------------------------
Title: Flare activity on T Tau stars.
Authors: Worden, S. P.; Schneeberger, T. J.; Kuhn, J. R.; Africano,
J. L.
1981ApJ...244..520W Altcode:
Observations of short-period photometric fluctuations in T Tauri
stars show flarelike events. These events are consistent with the
superposition of many solar-like flare events and have a power-spectrum
frequency dependence of ∼f<SUP>-2</SUP>. This dependence is the same
as that observed on UV Ceti stars. The flare events are very powerful,
and the expected proton flux from these events may explain early solar
system abundance anomalies without recourse to nearby supernovae. The
flare events are consistent with the observations of mass loss in
these stars.
---------------------------------------------------------
Title: Global Scale Photospheric Velocity Fields: Probes of the
Solar Interior.
Authors: Kuhn, J. R.
1981PhDT.........2K Altcode:
The integrity of the theory of stellar evolution depends on agreement
between the sun and its models. There are inconsistencies, though,
which will only be resolved by a more complete understanding of the
solar interior. This will likely come from photospheric measurements of
parameters that are sensitive to the interior conditions. Large scale
photospheric velocity fields are one such probe. This work describes
an attempt to measure the long term behavior of global scale fields,
with an eye toward understanding the conditions below the surface that
largely determine these velocity patterns. This paper reports on: (1) a
4-sigma detection of convective eddies rotating at the photospheric rate
with transverse spatial scales of order 10('5)km, (2) a 3m/s bound to
the amplitude of long period global photospheric velocity oscillations,
and (3) a new method for Fourier analysing unevenly sampled data.
---------------------------------------------------------
Title: Global scale photospheric velocity fields: probes of the
solar interior
Authors: Kuhn, Jeffrey Richard
1981PhDT.......160K Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Large Scale Solar Velocity Features
Authors: Kuhn, J. R.; Worden, S. P.
1980BAAS...12..473K Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Evidence of long-period velocity fluctuations.
Authors: Kuhn, J. R.; Worden, S. P.
1979ApJ...228L.119K Altcode:
Evidence of a solar fluctuation with a period of 17 days is observed
in spectroscopic differential-rotation data by using a technique
developed to look at long time sequences of unevenly spaced data. Both
spectroscopic observations and sunspot drift-velocity measurements
indicate a possible periodicity between 184 and 364 days. The sunspot
data marginally show fluctuations with periods which are multiples of
4.2 days.
---------------------------------------------------------
Title: Evidence of Long Period Solar Velocity Fluctuations
Authors: Kuhn, J. R.; Worden, S. P.
1978BAAS...10..639K Altcode:
No abstract at ADS
