explanation blue bibcodes open ADS page with paths to full text
Author name code: jaeggli
ADS astronomy entries on 2022-09-14
author:"Jaeggli, Sarah A."
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Title: A Publicly Available Multiobservatory Data Set of an Enhanced
Network Patch from the Photosphere to the Corona
Authors: Kobelski, Adam R.; Tarr, Lucas A.; Jaeggli, Sarah A.; Luber,
Nicholas; Warren, Harry P.; Savage, Sabrina
2022ApJS..261...15K Altcode: 2022arXiv220501766K
New instruments sensitive to chromospheric radiation at X-ray, UV,
visible, IR, and submillimeter wavelengths have become available that
significantly enhance our ability to understand the bidirectional
flow of energy through the chromosphere. We describe the calibration,
coalignment, initial results, and public release of a new data set
combining a large number of these instruments to obtain multiwavelength
photospheric, chromospheric, and coronal observations capable of
improving our understanding of the connectivity between the photosphere
and the corona via transient brightenings and wave signatures. The
observations center on a bipolar region of enhanced-network
magnetic flux near disk center on SOL2017-03-17T14:00-17:00. The
comprehensive data set provides one of the most complete views to
date of chromospheric activity related to small-scale brightenings
in the corona and chromosphere. Our initial analysis shows a strong
spatial correspondence between the areas of broadest width of the
hydrogen-α spectral line and the hottest temperatures observed in
Atacama Large Millimeter/submillimeter Array (ALMA) Band 3 radio
data, with a linear coefficient of 6.12 × 10<SUP>-5</SUP>Å/K. The
correspondence persists for the duration of cotemporal observations
(≍60 m). Numerous transient brightenings were observed in multiple
data series. We highlight a single, well-observed transient brightening
in a set of thin filamentary features with a duration of 20 minutes. The
timing of the peak intensity transitions from the cooler (ALMA, 7000 K)
to the hotter (XRT, 3 MK) data series.
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Title: Ground-based instrumentation and observational techniques
Authors: Rimmele, Thomas; Kuhn, Jeff; Woeger, Friedrich; Tritschler,
. Alexandra; Lin, Haosheng; Casini, Roberto; Schad, Thomas; Jaeggli,
Sarah; de Wijn, Alfred; Fehlmann, Andre; Anan, Tetsu; Schmidt, Dirk
2022cosp...44.2507R Altcode:
We'll review the current state-of-the-art for ground-based
instrumentation and techniques to achieve high-resolution
observations. We'll use the 4m Daniel K. Inouye Solar Telescope
(DKIST), the European Solar Telescope (EST) and other ground-based
instrumentation as examples to demonstrate instrument designs
and observing techniques. Using adaptive optics and post-facto
image processing techniques, the recently completed DKIST provides
unprecedented resolution and high polarimetric sensitivity that
enables 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. Versatile
ground-based instruments provide highly sensitive measurements of solar
magnetic fields, that in the case of DKIST, also include measurements
of the illusive magnetic field of the faint solar corona. Ground-based
instruments produce large and diverse data sets that require complex
calibration and data processing to provide science-ready to a broad
community. We'll briefly touch on ongoing and future instrumentation
developments, including multi-conjugate adaptive optics.
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Title: Science Commissioning of the Diffraction-Limited Near-IR
Spectropolarimter for the Daniel K. Inouye Solar Telescope
Authors: Lin, Haosheng; Schad, Thomas; Kramar, Maxim; Jaeggli, Sarah;
Anan, Tetsu; Onaka, Peter
2022cosp...44.2508L Altcode:
The Diffraction-Limited Near-IR Spectropolarimeter (DL-NIRSP) is one
of the first-generation facility instruments of the Daniel K. Inouye
Solar Telescope (DKIST, or The Inouye Solar Telescope). It is a near-IR
spectropolarimeter optimized to study the magnetism of the dynamic solar
atmosphere, from the photosphere to the corona. DL-NIRSP is equipped
with two integral field units (IFUs) coupled to a high-resolution
grating spectrograph, and is capable of simultaneous measurements
of the full polarized spectra of a 2-dimensional spatial field
without scanning. Large field of view observations are supported by
mosaicking. DL-NIRSP observes simultaneously at three spectral windows,
enabling simultaneous coverage of different atmospheric layers with
carefully selected spectral lines. It can also observe the Sun with
three resolution modes, from diffraction-limited observations with
a spatial sampling of 0.03" to wide-field mode covering a 32"x15"
instantaneous FOV with 0.5" sampling. This paper will present results
from science commissioning observations conducted in late 2021.
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Title: Thomson Scattering above Solar Active Regions and an Ad Hoc
Polarization Correction Method for the Emissive Corona
Authors: Schad, Thomas A.; Jaeggli, Sarah A.; Dima, Gabriel I.
2022ApJ...933...53S Altcode: 2022arXiv220509808S
Thomson-scattered photospheric light is the dominant constituent
of the lower solar corona's spectral continuum viewed off-limb at
optical wavelengths. Known as the K-corona, it is also linearly
polarized. We investigate the possibility of using the a priori
polarized characteristics of the K-corona, together with polarized
emission lines, to measure and correct instrument-induced polarized
crosstalk. First we derive the Stokes parameters of the Thomson
scattering of unpolarized light in an irreducible spherical tensor
formalism. This allows forward synthesis of the Thomson-scattered signal
for the more complex scenario that includes symmetry-breaking features
in the incident radiation field, which could limit the accuracy of our
proposed technique. For this, we make use of an advanced 3D radiative
magnetohydrodynamic coronal model. Together with synthesized polarized
signals in the Fe XIII 10746 Å emission line, we find that an ad hoc
correction of telescope- and instrument-induced polarization crosstalk
is possible under the assumption of a nondepolarizing optical system.
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Title: A Model-based Technique for Ad Hoc Correction of Instrumental
Polarization in Solar Spectropolarimetry
Authors: Jaeggli, Sarah A.; Schad, Thomas A.; Tarr, Lucas A.;
Harrington, David M.
2022ApJ...930..132J Altcode: 2022arXiv220403732J
We present a new approach for correcting instrumental polarization by
modeling the nondepolarizing effects of a complex series of optical
elements to determine physically realizable Mueller matrices. Provided
that the Mueller matrix of the optical system can be decomposed into
a general elliptical diattenuator and general elliptical retarder,
it is possible to model the crosstalk between both the polarized and
unpolarized states of the Stokes vector and then use the acquired
science observations to determine the best-fit free parameters. Here
we implement a minimization for solar spectropolarimetric measurements
containing photospheric spectral lines sensitive to the Zeeman effect
using physical constraints provided by polarized line and continuum
formation. This model-based approach is able to provide an accurate
correction even in the presence of large amounts of polarization
crosstalk and conserves the physically meaningful magnitude of
the Stokes vector, a significant improvement over previous ad hoc
techniques.
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Title: Probing the Physics of the Solar Atmosphere with the Multi-slit
Solar Explorer (MUSE). II. Flares and Eruptions
Authors: Cheung, Mark C. M.; Martínez-Sykora, Juan; Testa, Paola;
De Pontieu, Bart; Chintzoglou, Georgios; Rempel, Matthias; Polito,
Vanessa; Kerr, Graham S.; Reeves, Katharine K.; Fletcher, Lyndsay; Jin,
Meng; Nóbrega-Siverio, Daniel; Danilovic, Sanja; Antolin, Patrick;
Allred, Joel; Hansteen, Viggo; Ugarte-Urra, Ignacio; DeLuca, Edward;
Longcope, Dana; Takasao, Shinsuke; DeRosa, Marc L.; Boerner, Paul;
Jaeggli, Sarah; Nitta, Nariaki V.; Daw, Adrian; Carlsson, Mats; Golub,
Leon; The
2022ApJ...926...53C Altcode: 2021arXiv210615591C
Current state-of-the-art spectrographs cannot resolve the fundamental
spatial (subarcseconds) and temporal (less than a few tens of
seconds) scales of the coronal dynamics of solar flares and eruptive
phenomena. The highest-resolution coronal data to date are based on
imaging, which is blind to many of the processes that drive coronal
energetics and dynamics. As shown by the Interface Region Imaging
Spectrograph for the low solar atmosphere, we need high-resolution
spectroscopic measurements with simultaneous imaging to understand the
dominant processes. In this paper: (1) we introduce the Multi-slit Solar
Explorer (MUSE), a spaceborne observatory to fill this observational
gap by providing high-cadence (<20 s), subarcsecond-resolution
spectroscopic rasters over an active region size of the solar transition
region and corona; (2) using advanced numerical models, we demonstrate
the unique diagnostic capabilities of MUSE for exploring solar coronal
dynamics and for constraining and discriminating models of solar flares
and eruptions; (3) we discuss the key contributions MUSE would make
in addressing the science objectives of the Next Generation Solar
Physics Mission (NGSPM), and how MUSE, the high-throughput Extreme
Ultraviolet Solar Telescope, and the Daniel K Inouye Solar Telescope
(and other ground-based observatories) can operate as a distributed
implementation of the NGSPM. This is a companion paper to De Pontieu
et al., which focuses on investigating coronal heating with MUSE.
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Title: Probing the Physics of the Solar Atmosphere with the Multi-slit
Solar Explorer (MUSE): II. Flares and Eruptions
Authors: Cheung, Chun Ming Mark; Martinez-Sykora, Juan; Testa, Paola;
De Pontieu, Bart; Chintzoglou, Georgios; Rempel, Matthias; Polito,
Vanessa; Kerr, Graham; Reeves, Katharine; Fletcher, Lyndsay; Jin,
Meng; Nobrega, Daniel; Danilovic, Sanja; Antolin, Patrick; Allred,
Joel; Hansteen, Viggo; Ugarte-Urra, Ignacio; DeLuca, Edward; Longcope,
Dana; Takasao, Shinsuke; DeRosa, Marc; Boerner, Paul; Jaeggli, Sarah;
Nitta, Nariaki; Daw, Adrian; Carlsson, Mats; Golub, Leon
2021AGUFMSH51A..08C Altcode:
Current state-of-the-art spectrographs cannot resolve the fundamental
spatial (sub-arcseconds) and temporal scales (less than a few tens
of seconds) of the coronal dynamics of solar flares and eruptive
phenomena. The highest resolution coronal data to date are based on
imaging, which is blind to many of the processes that drive coronal
energetics and dynamics. As shown by IRIS for the low solar atmosphere,
we need high-resolution spectroscopic measurements with simultaneous
imaging to understand the dominant processes. In this paper: (1)
we introduce the Multi-slit Solar Explorer (MUSE), a spaceborne
observatory to fill this observational gap by providing high-cadence
(<20 s), sub-arcsecond resolution spectroscopic rasters over an
active region size of the solar transition region and corona; (2)
using advanced numerical models, we demonstrate the unique diagnostic
capabilities of MUSE for exploring solar coronal dynamics, and for
constraining and discriminating models of solar flares and eruptions;
(3) we discuss the key contributions MUSE would make in addressing the
science objectives of the Next Generation Solar Physics Mission (NGSPM),
and how MUSE, the high-throughput EUV Solar Telescope (EUVST) and the
Daniel K Inouye Solar Telescope (and other ground-based observatories)
can operate as a distributed implementation of the NGSPM. This is a
companion paper to De Pontieu et al. (2021, also submitted to SH-17),
which focuses on investigating coronal heating with MUSE.
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Title: Chromospheric Heating Mechanisms in a Plage Region Constrained
by Comparison of Magnetic Field and Mg II h & k Flux Measurements
with Theoretical Studies
Authors: Anan, Tetsu; Schad, Thomas; Kitai, Reizaburo; Dima, Gabriel;
Jaeggli, Sarah; Tarr, Lucas; Collados, Manuel; Dominguez-Tagle,
Carlos; Kleint, Lucia
2021AGUFMSH44A..05A Altcode:
The strongest quasi-steady heating in the solar atmosphere from the
photosphere through the corona occurs in plage regions. As many
chromospheric heating mechanisms have been proposed, important
discriminators of the possible mechanisms are the location of the
heating and the correlation between the magnetic field properties in
the chromosphere and the local heating rate. We observed a plage region
with the He I 1083.0 nm and Si I 1082.7 nm lines on 2018 October 3
using the integral field unit mode of the GREGOR Infrared Spectrograph
(GRIS) installed at the GREGOR telescope. During the GRIS observation,
the Interface Region Imaging Spectrograph (IRIS) obtained spectra of the
ultraviolet Mg II h & k doublet emitted from the same region. In
the periphery of the plage region, within the limited field of view
seen by GRIS, we find that the Mg II radiative flux increases with the
magnetic field in the chromosphere. The positive correlation implies
that magnetic flux tubes can be heated by Alfvén wave turbulence
or by collisions between ions and neutral atoms relating to Alfvén
waves. Within the plage region itself, the radiative flux was large
between patches of strong magnetic field strength in the photosphere, or
at the edges of magnetic patches. On the other hand, we do not find any
significant spatial correlation between the enhanced radiative flux and
the chromospheric magnetic field strength or the electric current. In
addition to the Alfvén wave turbulence or collisions between ions
and neutral atoms relating to Alfvén waves, other heating mechanisms
related to magnetic field perturbations produced by interactions of
magnetic flux tubes could be at work in the plage chromosphere.
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Title: Measurements of Photospheric and Chromospheric Magnetic
Field Structures Associated with Chromospheric Heating over a Solar
Plage Region
Authors: Anan, Tetsu; Schad, Thomas A.; Kitai, Reizaburo; Dima,
Gabriel I.; Jaeggli, Sarah A.; Tarr, Lucas A.; Collados, Manuel;
Dominguez-Tagle, Carlos; Kleint, Lucia
2021ApJ...921...39A Altcode: 2021arXiv210807907A
In order to investigate the relation between magnetic structures and
the signatures of heating in plage regions, we observed a plage region
with the He I 1083.0 nm and Si I 1082.7 nm lines on 2018 October 3
using the integral field unit mode of the GREGOR Infrared Spectrograph
(GRIS) installed at the GREGOR telescope. During the GRIS observation,
the Interface Region Imaging Spectrograph obtained spectra of the
ultraviolet Mg II doublet emitted from the same region. In the periphery
of the plage region, within the limited field of view seen by GRIS,
we find that the Mg II radiative flux increases with the magnetic
field in the chromosphere with a factor of proportionality of 2.38 ×
10<SUP>4</SUP> erg cm<SUP>-2</SUP> s<SUP>-1</SUP> G<SUP>-1</SUP>. The
positive correlation implies that magnetic flux tubes can be heated
by Alfvén wave turbulence or by collisions between ions and neutral
atoms relating to Alfvén waves. Within the plage region itself,
the radiative flux was large between patches of strong magnetic field
strength in the photosphere or at the edges of magnetic patches. On
the other hand, we do not find any significant spatial correlation
between the enhanced radiative flux and the chromospheric magnetic
field strength or the electric current. In addition to the Alfvén
wave turbulence or collisions between ions and neutral atoms relating
to Alfvén waves, other heating mechanisms related to magnetic field
perturbations produced by interactions of magnetic flux tubes could
be at work in the plage chromosphere.
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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: Magnetic field structures associated with chromospheric
heating in a plage region
Authors: Anan, T.; Schad, T.; Kitai, R.; Dima, G.; Jaeggli, S.;
Collados, M.; Dominguez-Tagle, C.; Kleint, L.
2021AAS...23821222A Altcode:
The strongest quasi-steady heating in the solar atmosphere occurs in
the active chromosphere and in particular within plage regions. Our
aim is to investigate the relation between magnetic structures and
the signatures of heating in the plage regions so as to clarify what
mechanisms are at work. We observed a plage region in NOAA active
region 12723 in the near infrared He I triplet and Si I 1082.7 nm
on 2018 October 3 using the Integral Field Unit mode of the GREGOR
Infrared Spectrograph (GRIS) installed at the GREGOR telescope. At the
same time, the Interface Region Imaging Spectrograph (IRIS) obtained
spectra in the ultra-violet Mg II h & k doublet emitted from the
same region. We applied the HAnle and ZEeman Light v2.0 inversion
code (HAZEL v2.0) to the GRIS data to infer the photospheric and
chromospheric magnetic field. We find that the radiative flux of the Mg
II was large between patches of strong magnetic field strength in the
photosphere, or at edges of the magnetic patches. On the other hand,
the spatial correspondences between the Mg II flux and the magnetic
field strength in the chromosphere and between the Mg II flux and the
electric current are not so clear. In conclusion, chromospheric heatings
in the plage region can be related to magnetic field perturbations
produced by interactions of magnetic flux tubes.
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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 Molecules to Investigate Cool Gas on the Sun with DKIST
Authors: Jaeggli, Sarah
2021cosp...43E.970J Altcode:
Simple molecules form in the solar atmosphere in regions of cool
plasma. Molecules are physically interesting and provide critical
diagnostics of cool plasma. They are sensitive to temperature
and pressure, and some molecular lines are even magnetically
sensitive. Strong absorption lines from molecules such as OH,
CN, and CO are prominent in sunspot spectra. Molecular hydrogen,
which has a noted absence of lines in the visible and infrared, may
actually be the most abundant molecular species, comprising 10% of the
total hydrogen population in very cool sunspot umbrae. CH, which is
ubiquitous in the quiet-Sun, dissociates in hotter regions, revealing
the features known as G-band bright points. The strongest lines of
the fundamental band of CO at 4.6 um reveal what has been interpreted
as a mix of hot and cool gas at the roots of the chromosphere. The
U.S. National Science Foundation's Daniel K. Inouye Solar Telescope
(DKIST) will provide new observations of the Sun with unprecedented
spatial and temporal resolution. DKIST instruments are designed
to target atomic and molecular diagnostics to address a variety of
science cases. Molecular diagnostics throughout the visible spectrum
can be explored with the Visible Spectropolarimeter (ViSP). The
Diffraction-Limited Near-Infrared Spectropolarimeter (DL-NIRSP) can
be used to explore the dynamic behavior of OH in sunspots alongside
sensitive magnetic field diagnostics of Fe I at 1565 nm using its
integral field unit. The Cryogenic Near-Infrared Spectropolarimeter
will provide the chance for detailed study of the 4.6 um CO lines on
disk and at the limb.
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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: Polarization modeling and predictions for Daniel K. Inouye
Solar Telescope, part 6: fringe mitigation with polycarbonate
modulators and optical contact calibration retarders
Authors: Harrington, David M.; Jaeggli, Sarah A.; Schad, Tom A.;
White, Amanda J.; Sueoka, Stacey R.
2020JATIS...6c8001H Altcode:
Interference fringes are a major source of systematic error in
astronomical spectropolarimeters. We apply the Berreman formalism
with recent spatial fringe aperture averaging estimates to design and
fabricate new fringe-suppressed polarization optics for several Daniel
K. Inouye Solar Telescope (DKIST) use cases. We successfully performed
an optical contact bond on a 120-mm-diameter compound crystal retarder
for calibration with wavelength-dependent fringe suppression factors
of one to three orders of magnitude. Special rotational alignment
procedures were developed to minimize spectral oscillations, which
we show here to represent our calibration stability limit under
retarder thermal perturbation. We developed a fabrication technique
to deliver low beam deflection for our large aperture polycarbonate
(PC) retarders. Modulators are upgraded in two DKIST instruments
with minimal beam deflection and bandpass-optimized antireflection
coatings for fringe suppression factors of hundreds. We confirm that
PC retarders do fringe as expected when low deflection is achieved. We
show that increased retardance spatial variation from PC does not
degrade modulation efficiency.
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Title: Observing Solar Plasma Environments with DKIST
Authors: Jaeggli, Sarah
2020APS..DPPD02001J Altcode:
The Sun displays diverse plasma environments structured by magnetic
fields. The largely neutral photosphere is sprinkled with ∼1 kG
magnetic fields rooted in the underlying convection zone. Just above
this magneto-acoustic shocks and rapidly expanding magnetic fields
create complex and dynamic structures interspersed with quiescent
and eruptive phenomena in the chromosphere. The average temperature
increases through the chromosphere abruptly jumps to >10<SUP>6</SUP>
K in the solar corona. These different regimes are directly coupled by
many processes that have been extensively studied using a combination
of theory, simulations, and laboratory experiments: dynamos, waves,
instabilities, and reconnection. The National Science Foundation's
Daniel K. Inouye Solar Telescope is an unprecedented new facility that
will allow for measurements of the highest spatial resolution and superb
signal to noise on shorter timescales than ever before. First light
instruments will provide simultaneous multi-wavelength observations
with spectral and polarimetric capabilities on disk and above the
limb. Coupled with radiative MHD modeling, this can provide 3D diagnosis
of plasma parameters (e.g. magnetic field vector, temperature) over
the plasma regimes found throughout the Sun's atmosphere.
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Title: Shock Heating Energy of Umbral Flashes Measured with Integral
Field Unit Spectroscopy
Authors: Anan, Tetsu; Schad, Thomas A.; Jaeggli, Sarah A.; Tarr,
Lucas A.
2019ApJ...882..161A Altcode: 2019arXiv190710797A
Umbral flashes are periodic brightness increases routinely observed in
the core of chromospheric lines within sunspot umbrae and are attributed
to propagating shock fronts. In this work we quantify the shock heating
energy of these umbral flashes using observations in the near-infrared
He I triplet obtained on 2014 December 7 with the SpectroPolarimetric
Imager for the Energetic Sun, which is a novel integral field unit
spectrograph at the Dunn Solar Telescope. We determine the shock
properties (the Mach number and the propagation speed) by fitting
the measured He I spectral profiles with a theoretical radiative
transfer model consisting of two constant-property atmospheric slabs
whose temperatures and macroscopic velocities are constrained by the
Rankine-Hugoniot relations. From the Mach number, the shock heating
energy per unit mass of plasma is derived to be 2 × 10<SUP>10</SUP>
erg g<SUP>-1</SUP>, which is insufficient to maintain the umbral
chromosphere. In addition, we find that the shocks propagate upward with
the sound speed and the Mach number does not depend on the temperature
upstream of the shocks. The latter may imply suppression of the
amplification of the Mach number due to energy loss of the shocks.
---------------------------------------------------------
Title: Optical Alignment of DL-NIRSP Spectrograph
Authors: Jaeggli, Sarah A.; Anan, Tetsu; Kramar, Maxim; Lin, Haosheng
2019AAS...23410612J Altcode:
The Diffraction-Limited Near-Infrared Spectropolarimeter (DL-NIRSP)
will be delivered as part of the first light instrumentation for the
Daniel K. Inouye Solar Telescope (DKIST) and is currently undergoing
lab integration at the University of Hawai'i Institute for Astronomy's
Advanced Technology Research Center on Maui. An off-axis hyperbolic
mirror, with a focal length of 1250 mm, is used as both collimator
and camera in the spectrograph, and makes this system particularly
difficult to align. The optical axis, or vertex, of the parent surface
is located approximately 260 mm from the center of the off-axis
section of the mirror, but there is no direct physical or optical
reference for the location and orientation of the optical axis. We
have made use of vendor data and a coordinate measuring machine (CMM)
arm to transfer coordinates from the back and perimeter surfaces of
the mirror to locate the optical axis focus and place the other optical
components in reference to this mechanical model. In coordination, we
have conducted tests of the optical quality at various points during
the alignment to ensure that the mechanical tolerances maintain the
optical quality of the system so that the instrument will be able to
achieve excellent spectral resolution limited by the spectrograph slit
width (λ/Δλ 250,000), and preserve the diffraction limited spatial
resolution provided by the telescope and feed optics (0.06" at 1 μm).
---------------------------------------------------------
Title: Transient dynamics and energy transfer from the photosphere
to the low corona: initial results from a coordinated ALMA, DST,
Hinode, IRIS, and SDO observation campaign
Authors: Kobelski, Adam; Tarr, Lucas A.; Jaeggli, Sarah A.; Savage,
Sabrina
2019AAS...23430702K Altcode:
We present initial results from a coordinated observation campaign
to study transient dynamics and energy transfer in the low solar
atmosphere. The observations ran from approximately 2017-03-21 from
13UT to 19UT, and include data from Hinode, IRIS, DST, and ALMA. The
target, a small, magnetically bipolar active area associated with a
coronal bright point, was chosen for showing reasonable dynamics in the
chromosphere (as dictated by AIA 304 data from the day prior), and being
near disk center to better facilitate magnetic field measurement. The
campaign was designed to capture the dynamics of the target with as
rapid a timescale as possible for each instrument. Photospheric dynamics
are available from broadband IBIS data and the HMI. New to this dataset,
the chromospheric dynamics were observed in radio frequencies using ALMA
(Band 3: 92-108GHz) at a 2s cadence. Additional chromospheric data are
spectral H-α from the IBIS instrument at the DST, spectropolarimetic
HeI 10830 from the FIRS instrument at the DST, and the medium linelist
from IRIS; coronal data includes imaging from XRT and spectral data
from EIS. In this first set of results, we discuss the frequency of
transient brightenings observed in each set of imaging data and how
the spatial distribution relates across each data channel and to the
regions magnetic topology.
---------------------------------------------------------
Title: Shock heating energy in an umbra of a sunspot with integral
field unit spectroscopy
Authors: Anan, Tetsu; Schad, Thomas A.; Jaeggli, Sarah A.; Tarr,
Lucas A.
2019AAS...23421705A Altcode:
On 2014 December 7 we used new integral field spectroscopy techniques
to observe umbral flashes, which are periodic brightness increases
routinely observed in the core of chromospheric lines within sunspot
umbrae and are attributed to propagating shock fronts. In this work
we quantify the shock heating energy of these umbral flashes using
observations in the near infrared HeI triplet obtained with the
SpectroPolarimetric Imager for the Energetic Sun (SPIES), which is
novel integral field unit spectrograph at the Dunn Solar Telescope. We
determine the shock properties (the Mach number and the propagation
speed) by fitting the measured HeI spectral profiles with a theoretical
radiative transfer model using two constant property atmospheric slabs
whose temperatures and macroscopic velocities are constrained by the
Rankine-Hugoniot relations. From the Mach number, the shock heating
energy per unit mass of plasma is derived as 2 x 10<SUP>10</SUP>
erg/g. We conclude that the estimated shock heating energy rate is
less than the amount required to maintain the umbral chromosphere.
---------------------------------------------------------
Title: Shock Heating Energy in an umbra of a sunspot
Authors: Anan, Tetsu; Schad, Tom; Jaeggli, Sarah
2019EGUGA..2113543A Altcode:
In December 7, 2014, umbral flashes, which are periodic brightness
increases in chromospheric spectral lines of the umbrae due to shocks,
were observed in near infrared He I triplet with an integral-field-unit
spectrometer, SPIES (SpectroPolarimetric Imager for the Energetic Sun)
on the Dunn Solar Telescope with a cadence of 14 seconds. The SPIES is
a prototype instruments of a facility instrument of the Daniel K. Inouye
Solar Telescope. In order to determine Mach number at upstream of shock
waves, we fit the measured spectral profiles in the He I 1083 nm triplet
with theoretical profiles computed with a radiative transfer equation
using an atmospheric model based on two constant property slabs, of
which temperatures and macroscopic velocities are constrained by the
Rankine-Hugoniot relations. From the Mach number and the temperature,
shock heating energy per unit mass of plasma is derived as 2.0 x 10 ^
{10} erg/g. Finding a positive correlation between a spatial variation
of the chromospheric temperature and shock speed, we concluded that
prominent heating mechanism can be related with the shock, although
estimated shock heating energy rate is less than the required amount
of energy to maintain the umbral chromosphere.
---------------------------------------------------------
Title: VizieR Online Data Catalog: UV spectrum of molecular hydrogen
in the Sun (Jaeggli+, 2018)
Authors: Jaeggli, S. A.; Judge, P. G.; Daw, A. N.
2019yCat..18550134J Altcode:
Ultraviolet (UV) lines of molecular hydrogen have been observed in
solar spectra for almost four decades, but the behavior of the molecular
spectrum and its implications for solar atmospheric structure are not
fully understood. Data from the High-Resolution Telescope Spectrometer
(HRTS) instrument revealed that H2 emission forms in particular regions,
selectively excited by a bright UV transition region and chromospheric
lines. We test the conditions under which H2 emission can originate
by studying non-LTE models, sampling a broad range of temperature
stratifications and radiation conditions. Stratification plays the
dominant role in determining the population densities of H2, which
forms in greatest abundance near the continuum photosphere. However,
opacity due to the photoionization of Si and other neutrals determines
the depth to which UV radiation can penetrate to excite the H2. Thus
the majority of H2 emission forms in a narrow region, at about 650km
in standard one-dimensional (1D) models of the quiet Sun, near the
{tau}=1 opacity surface for the exciting UV radiation, generally coming
from above. When irradiated from above using observed intensities of
bright UV emission lines, detailed non-LTE calculations show that the
spectrum of H2 seen in the quiet-Sun Solar Ultraviolet Measurement of
Emitted Radiation atlas spectrum and HRTS light-bridge spectrum can
be satisfactorily reproduced in 1D stratified atmospheres, without
including three-dimensional or time-dependent thermal structures. A
detailed comparison to observations from 1205 to 1550Å is presented,
and the success of this 1D approach to modeling solar UV H2 emission
is illustrated by the identification of previously unidentified lines
and upper levels in HRTS spectra. <P />(3 data files).
---------------------------------------------------------
Title: Instrument Calibration of the Interface Region Imaging
Spectrograph (IRIS) Mission
Authors: Wülser, J. -P.; Jaeggli, S.; De Pontieu, B.; Tarbell,
T.; Boerner, P.; Freeland, S.; Liu, W.; Timmons, R.; Brannon, S.;
Kankelborg, C.; Madsen, C.; McKillop, S.; Prchlik, J.; Saar, S.;
Schanche, N.; Testa, P.; Bryans, P.; Wiesmann, M.
2018SoPh..293..149W Altcode:
The Interface Region Imaging Spectrograph (IRIS) is a NASA small
explorer mission that provides high-resolution spectra and images of
the Sun in the 133 - 141 nm and 278 - 283 nm wavelength bands. The
IRIS data are archived in calibrated form and made available to the
public within seven days of observing. The calibrations applied to
the data include dark correction, scattered light and background
correction, flat fielding, geometric distortion correction, and
wavelength calibration. In addition, the IRIS team has calibrated the
IRIS absolute throughput as a function of wavelength and has been
tracking throughput changes over the course of the mission. As a
resource for the IRIS data user, this article describes the details
of these calibrations as they have evolved over the first few years
of the mission. References to online documentation provide access to
additional information and future updates.
---------------------------------------------------------
Title: Predictions of DKIST/DL-NIRSP Observations for an Off-limb
Kink-unstable Coronal Loop
Authors: Snow, B.; Botha, G. J. J.; Scullion, E.; McLaughlin, J. A.;
Young, P. R.; Jaeggli, S. A.
2018ApJ...863..172S Altcode: 2018arXiv180704972S
Synthetic intensity maps are generated from a 3D kink-unstable flux
rope simulation using several DKIST/DL-NIRSP spectral lines to make
a prediction of the observational signatures of energy transport and
release. The reconstructed large field-of-view intensity mosaics and
single tile sit-and-stare high-cadence image sequences show detailed,
fine-scale structure and exhibit signatures of wave propagation,
redistribution of heat, flows, and fine-scale bursts. These fine-scale
bursts are present in the synthetic Doppler velocity maps and can be
interpreted as evidence for small-scale magnetic reconnection at the
loop boundary. The spectral lines reveal the different thermodynamic
structures of the loop, with the hotter lines showing the loop
interior and braiding and the cooler lines showing the radial edges
of the loop. The synthetic observations of DL-NIRSP are found to
preserve the radial expansion, and hence the loop radius can be
measured accurately. The electron number density can be estimated
using the intensity ratio of the Fe XIII lines at 10747 and 10798
Å. The estimated density from this ratio is correct to within ±10%
during the later phases of the evolution; however, it is less accurate
initially when line-of-sight density inhomogeneities contribute to the
Fe XIII intensity, resulting in an overprediction of the density by
≈30%. The identified signatures are all above a conservative estimate
for instrument noise and therefore will be detectable. In summary, we
have used forward modeling to demonstrate that the coronal off-limb
mode of DKIST/DL-NIRSP will be able to detect multiple independent
signatures of a kink-unstable loop and observe small-scale transient
features including loop braiding/twisting and small-scale reconnection
events occurring at the radial edge of the loop.
---------------------------------------------------------
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: Solar UV Molecular Hydrogen Fluorescence
Authors: Daw, Adrian Nigel; Jaeggli, Sarah Amelia; Judge, Philip G.;
Roueff, Evelyne; Abgrall, Hervé
2018tess.conf21706D Altcode:
Solar observations of ultraviolet molecular hydrogen lines indicate
that H<SUB>2</SUB> emission forms in particular regions, selectively
excited by bright UV transition region and chromospheric lines. IRIS
frequently observes numerous H<SUB>2</SUB> lines during flares and
smaller energetic events, but the diagnostic value of these lines for
probing the structure of the solar atmosphere has heretofore remained
largely unexploited. We present a synthesis method for H<SUB>2</SUB>
emission, using 1-D non-LTE models sampling a broad range of temperature
stratifications and input radiation conditions from the atmosphere
above, and compare the results to observations by IRIS, SUMER and
HRTS from 1205 to 1550 Å. Because opacity due to photoionization of
silicon and other neutrals determines the depth to which UV radiation
can penetrate to excite the H<SUB>2</SUB>, the majority of H<SUB>2</SUB>
emission forms in a narrow region near the tau=1 opacity surface for
the exciting UV radiation, generally coming from above. The success
of this 1-D approach to modeling solar UV H<SUB>2</SUB> emission is
illustrated by the identification of previously unidentified lines and
upper levels. Applications of the observed emission and implications
for solar atmospheric structure are discussed.
---------------------------------------------------------
Title: Formation of the UV Spectrum of Molecular Hydrogen in the Sun
Authors: Jaeggli, S. A.; Judge, P. G.; Daw, A. N.
2018ApJ...855..134J Altcode: 2018arXiv180203779J
Ultraviolet (UV) lines of molecular hydrogen have been observed in
solar spectra for almost four decades, but the behavior of the molecular
spectrum and its implications for solar atmospheric structure are not
fully understood. Data from the High-Resolution Telescope Spectrometer
(HRTS) instrument revealed that H<SUB>2</SUB> emission forms in
particular regions, selectively excited by a bright UV transition
region and chromospheric lines. We test the conditions under which
H<SUB>2</SUB> emission can originate by studying non-LTE models,
sampling a broad range of temperature stratifications and radiation
conditions. Stratification plays the dominant role in determining
the population densities of H<SUB>2</SUB>, which forms in greatest
abundance near the continuum photosphere. However, opacity due to
the photoionization of Si and other neutrals determines the depth to
which UV radiation can penetrate to excite the H<SUB>2</SUB>. Thus
the majority of H<SUB>2</SUB> emission forms in a narrow region,
at about 650 km in standard one-dimensional (1D) models of the quiet
Sun, near the τ = 1 opacity surface for the exciting UV radiation,
generally coming from above. When irradiated from above using observed
intensities of bright UV emission lines, detailed non-LTE calculations
show that the spectrum of H<SUB>2</SUB> seen in the quiet-Sun Solar
Ultraviolet Measurement of Emitted Radiation atlas spectrum and HRTS
light-bridge spectrum can be satisfactorily reproduced in 1D stratified
atmospheres, without including three-dimensional or time-dependent
thermal structures. A detailed comparison to observations from 1205 to
1550 Å is presented, and the success of this 1D approach to modeling
solar UV H<SUB>2</SUB> emission is illustrated by the identification
of previously unidentified lines and upper levels in HRTS spectra.
---------------------------------------------------------
Title: Formation of the UV Spectrum of Molecular Hydrogen in the Sun
Authors: Jaeggli, S. A.; Judge, P. G.; Daw, A. N.
2017AGUFMSH52B..01J Altcode:
UV lines of molecular hydrogen in the Sun have been observed for almost
four decades, but the behavior of the spectra and their implications
for solar atmospheric structure are not fully understood. Data from the
HRTS instrument revealed that H2 emission forms in particular regions,
selectively excited by bright UV transition region and chromospheric
lines. We test the conditions under which H2 emission can originate
by studying non-LTE models with increasingly complex temperature
stratification. Stratification plays the dominant role in determining
the population densities of H2, which can form in abundance only within
about 700 km of the continuum photosphere where 3D and dynamic structure
generally play secondary roles to stratification. When irradiated
from above using observed intensities of bright UV emission lines,
detailed non-LTE calculations show that the spectrum of H2 can be
satisfactorily modeled in 1D stratified atmospheric models, with no
need to invoke unusual 3D or time dependent thermal structures.
---------------------------------------------------------
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: Large Scale Coordination of Small Scale Structures
Authors: Kobelski, Adam; Tarr, Lucas A.; Jaeggli, Sarah A.; Savage,
Sabrina
2017SPD....4820005K Altcode:
Transient brightenings are ubiquitous features of the solar atmosphere
across many length and energy scales, the most energetic of which
manifest as large-class solar flares. Often, transient brightenings
originate in regions of strong magnetic activity and create strong
observable enhancements across wavelengths from X-ray to radio, with
notable dynamics on timescales of seconds to hours.The coronal aspects
of these brightenings have often been studied by way of EUV and X-ray
imaging and spectra. These events are likely driven by photospheric
activity (such as flux emergence) with the coronal brightenings
originating largely from chromospheric ablation (evaporation). Until
recently, chromospheric and transition region observations of these
events have been limited. However, new observational capabilities have
become available which significantly enhance our ability to understand
the bi-directional flow of energy through the chromosphere between the
photosphere and the corona.We have recently obtained a unique data set
with which to study this flow of energy through the chromosphere via
the Interface Region Imaging Spectrograph (IRIS), Hinode EUV Imaging
Spectrometer (EIS), Hinode X-Ray Telescope (XRT), Hinode Solar Optical
Telescope (SOT), Solar Dynamics Observatory (SDO) Atmospheric Imaging
Assembly (AIA), SDO Helioseismic and Magnetic Imager (HMI), Nuclear
Spectroscopic Telescope Array (NuStar), Atacama Large Millimeter Array
(ALMA), and Interferometric BIdimensional Spectropolarimeter (IBIS)
at the Dunn Solar Telescope (DST). This data set targets a small active
area near disk center which was tracked simultaneously for approximately
four hours. Within this region, many transient brightenings detected
through multiple layers of the solar atmosphere. In this study, we
combine the imaging data and use the spectra from EIS and IRIS to
track flows from the photosphere (HMI, SOT) through the chromosphere
and transition region (AIA, IBIS, IRIS, ALMA) into the corona (EIS,
XRT, AIA).
---------------------------------------------------------
Title: An Update on the Diffraction-Limited Near Infrared
Spectropolarimeter for the Daniel K. Inouye Solar Telescope
Authors: Jaeggli, Sarah A.; Lin, Haosheng; Onaka, Peter; McGregor,
Helen; Yamada, Hubert
2017SPD....4811704J Altcode:
DL-NIRSP is an integral field imaging spectropolarimeter for
photospheric, chromospheric, and coronal magnetic field studies
which is currently under development by the University of Hawaii’s
Institute for Astronomy as part of the first light instrument suite for
DKIST. DL-NIRSP pairs a multi-slit fiber-optic image slicer with narrow
bandpass isolation filters and large format detectors to achieve very
high cadence observations in three simultaneous wavelength channels
in the Visible-IR. Planned diagnostics at first light include Fe XI
789.2 nm, Ca II 854.2 nm, Fe XIII 1074.7 nm, Si I/He I 1083.0 nm, Si
X 1430.0 nm, and Fe I 1565.0 nm. More spectral lines will be added in
the future. As the last stop in the DKIST light distribution system,
DL-NIRSP will receive an AO corrected beam and will be able to operate
simultaneously with the other visible light instruments. We provide an
update on the current challenges and rewards yet to come with DL-NIRSP.
---------------------------------------------------------
Title: The Magnetic Classification of Solar Active Regions 1992-2015
Authors: Jaeggli, S. A.; Norton, A. A.
2016ApJ...820L..11J Altcode: 2016arXiv160302552J
The purpose of this Letter is to address a blindspot in our knowledge
of solar active region (AR) statistics. To the best of our knowledge,
there are no published results showing the variation of the Mount
Wilson magnetic classifications as a function of solar cycle based
on modern observations. We show statistics for all ARs reported in
the daily Solar Region Summary from 1992 January 1 to 2015 December
31. We find that the α and β class ARs (including all sub-groups,
e.g., βγ, βδ) make up fractions of approximately 20% and 80% of
the sample, respectively. This fraction is relatively constant during
high levels of activity however, an increase in the α fraction to
about 35% and and a decrease in the β fraction to about 65% can
be seen near each solar minimum and are statistically significant
at the 2σ level. Over 30% of all ARs observed during the years of
solar maxima were appended with the classifications γ and/or δ,
while these classifications account for only a fraction of a percent
during the years near the solar minima. This variation in the AR
types indicates that the formation of complex ARs may be due to the
pileup of frequent emergence of magnetic flux during solar maximum,
rather than the emergence of complex, monolithic flux structures.
---------------------------------------------------------
Title: Multi-wavelength Study of a Delta-spot. I. A Region of Very
Strong, Horizontal Magnetic Field
Authors: Jaeggli, S. A.
2016ApJ...818...81J Altcode: 2015arXiv151208463J
Active region NOAA 11035 appeared in 2009 December, early in the new
solar activity cycle. This region achieved a delta sunspot (δ spot)
configuration when parasitic flux emerged near the rotationally
leading magnetic polarity and traveled through the penumbra of the
largest sunspot in the group. Both visible and infrared imaging
spectropolarimetry of the magnetically sensitive Fe I line pairs at
6302 and 15650 Å show large Zeeman splitting in the penumbra between
the parasitic umbra and the main sunspot umbra. The polarized Stokes
spectra in the strongest field region display anomalous profiles,
and strong blueshifts are seen in an adjacent region. Analysis of
the profiles is carried out using a Milne-Eddington inversion code
capable of fitting either a single magnetic component with stray
light or two independent magnetic components to verify the field
strength. The inversion results show that the anomalous profiles cannot
be produced by the combination of two profiles with moderate magnetic
fields. The largest field strengths are 3500-3800 G in close proximity
to blueshifts as strong as 3.8 km s<SUP>-1</SUP>. The strong, nearly
horizontal magnetic field seen near the polarity inversion line in
this region is difficult to understand in the context of a standard
model of sunspot magnetohydrostatic equilibrium.
---------------------------------------------------------
Title: The Persistence of Apparent Non-Magnetostatic Equilibrium in
NOAA 11035
Authors: Jaeggli, Sarah A.
2015IAUS..305...35J Altcode: 2015arXiv150401325J
NOAA 11035 was a highly sheared active region that appeared in
December 2009 early in the new activity cycle. The leading polarity
sunspot developed a highly unusual feature in its penumbra, an
opposite polarity pore with a strong magnetic field in excess of
3500 G along one edge, which persisted for several days during the
evolution of the region. This region was well observed by both space-
and ground-based observatories, including Hinode, FIRS, TRACE, and
SOHO. These observations, which span wavelength and atmospheric regimes,
provide a complete picture of this unusual feature which may constitute
a force-free magnetic field in the photosphere which is produced by
the reconnection of magnetic loops low in the solar atmosphere.
---------------------------------------------------------
Title: A very strong magnetic field region in NOAA 11035
Authors: Jaeggli, Sarah Amelia
2015TESS....111304J Altcode:
NOAA 11035 was a fairly typical active region that emerged near
the central meridian 13-14 December 2009, early in solar cycle
24. During the active region’s rapid emergence and evolution, a
deeply-rooted magnetic bipole emerged into the pre-existing leading
polarity with spectacular consequences. Multi-wavelength imaging and
spectropolarimetry from FIRS, IBIS, Hinode, TRACE, and SOHO allow
for a comprehensive investigation of the physical processes present
in this region. Intrusion of the opposite polarity into the leading
sunspot’s penumbra resulted in a region of highly concentrated
horizontal magnetic field, with a peak field strength larger than 3600
G based on Milne-Eddington inversion of Fe I spectropolarimetry at
6302 and 15650 Å. Photospheric velocity measurements show blueshifts
of 4 km/sec along the neutral line, which are coincident with a dark
chromospheric structure in He I 10830 and H I 6563 Å. We conclude that
these signatures are the result of continuous magnetic reconnection
near photospheric heights.
---------------------------------------------------------
Title: Internetwork Chromospheric Bright Grains Observed With IRIS
and SST
Authors: Martínez-Sykora, Juan; Rouppe van der Voort, Luc; Carlsson,
Mats; De Pontieu, Bart; Pereira, Tiago M. D.; Boerner, Paul; Hurlburt,
Neal; Kleint, Lucia; Lemen, James; Tarbell, Ted D.; Title, Alan;
Wuelser, Jean-Pierre; Hansteen, Viggo H.; Golub, Leon; McKillop, Sean;
Reeves, Kathy K.; Saar, Steven; Testa, Paola; Tian, Hui; Jaeggli,
Sarah; Kankelborg, Charles
2015ApJ...803...44M Altcode: 2015arXiv150203490M
The Interface Region Imaging Spectrograph (IRIS) reveals small-scale
rapid brightenings in the form of bright grains all over coronal holes
and the quiet Sun. These bright grains are seen with the IRIS 1330,
1400, and 2796 Å slit-jaw filters. We combine coordinated observations
with IRIS and from the ground with the Swedish 1 m Solar Telescope
(SST) which allows us to have chromospheric (Ca ii 8542 Å, Ca ii H
3968 Å, Hα, and Mg ii k 2796 Å) and transition region (C ii 1334 Å,
Si iv 1403 Å) spectral imaging, and single-wavelength Stokes maps
in Fe i 6302 Å at high spatial (0\buildrel{\prime\prime}\over{.}
33), temporal, and spectral resolution. We conclude that the IRIS
slit-jaw grains are the counterpart of so-called acoustic grains,
i.e., resulting from chromospheric acoustic waves in a non-magnetic
environment. We compare slit-jaw images (SJIs) with spectra from the
IRIS spectrograph. We conclude that the grain intensity in the 2796
Å slit-jaw filter comes from both the Mg ii k core and wings. The
signal in the C ii and Si iv lines is too weak to explain the presence
of grains in the 1300 and 1400 Å SJIs and we conclude that the grain
signal in these passbands comes mostly from the continuum. Although
weak, the characteristic shock signatures of acoustic grains can often
be detected in IRIS C ii spectra. For some grains, a spectral signature
can be found in IRIS Si iv. This suggests that upward propagating
acoustic waves sometimes reach all the way up to the transition region.
---------------------------------------------------------
Title: Homologous Helical Jets: Observations By IRIS, SDO, and Hinode
and Magnetic Modeling With Data-Driven Simulations
Authors: Cheung, Mark C. M.; De Pontieu, B.; Tarbell, T. D.; Fu, Y.;
Tian, H.; Testa, P.; Reeves, K. K.; Martínez-Sykora, J.; Boerner,
P.; Wülser, J. P.; Lemen, J.; Title, A. M.; Hurlburt, N.; Kleint,
L.; Kankelborg, C.; Jaeggli, S.; Golub, L.; McKillop, S.; Saar, S.;
Carlsson, M.; Hansteen, V.
2015ApJ...801...83C Altcode: 2015arXiv150101593C
We report on observations of recurrent jets by instruments on board
the Interface Region Imaging Spectrograph, Solar Dynamics Observatory
(SDO), and Hinode spacecraft. Over a 4 hr period on 2013 July 21,
recurrent coronal jets were observed to emanate from NOAA Active Region
11793. Far-ultraviolet spectra probing plasma at transition region
temperatures show evidence of oppositely directed flows with components
reaching Doppler velocities of ±100 km s<SUP>-1</SUP>. Raster Doppler
maps using a Si iv transition region line show all four jets to have
helical motion of the same sense. Simultaneous observations of the
region by SDO and Hinode show that the jets emanate from a source
region comprising a pore embedded in the interior of a supergranule. The
parasitic pore has opposite polarity flux compared to the surrounding
network field. This leads to a spine-fan magnetic topology in the
coronal field that is amenable to jet formation. Time-dependent
data-driven simulations are used to investigate the underlying drivers
for the jets. These numerical experiments show that the emergence of
current-carrying magnetic field in the vicinity of the pore supplies
the magnetic twist needed for recurrent helical jet formation.
---------------------------------------------------------
Title: The 2014 March 29 X-flare: Subarcsecond Resolution Observations
of Fe XXI λ1354.1
Authors: Young, Peter R.; Tian, Hui; Jaeggli, Sarah
2015ApJ...799..218Y Altcode: 2014arXiv1409.8603Y
The Interface Region Imaging Spectrometer (IRIS) is the first solar
instrument to observe ~10 MK plasma at subarcsecond spatial resolution
through imaging spectroscopy of the Fe XXI λ1354.1 forbidden line. IRIS
observations of the X1 class flare that occurred on 2014 March 29 at
17:48 UT reveal Fe XXI emission from both the flare ribbons and the
post-flare loop arcade. Fe XXI appears at all of the chromospheric
ribbon sites, although typically with a delay of one raster (75 s) and
sometimes offset by up to 1”. 100-200 km s<SUP>-1</SUP> blue-shifts
are found at the brightest ribbons, suggesting hot plasma upflow into
the corona. The Fe XXI ribbon emission is compact with a spatial
extent of <2”, and can extend beyond the chromospheric ribbon
locations. Examples are found of both decreasing and increasing
blue-shift in the direction away from the ribbon locations, and
blue-shifts were present for at least six minutes after the flare
peak. The post-flare loop arcade, seen in Atmospheric Imaging Assembly
131 Å filtergram images that are dominated by Fe XXI, exhibited
bright loop-tops with an asymmetric intensity distribution. The sizes
of the loop-tops are resolved by IRIS at >=1”, and line widths
in the loop-tops are not broader than in the loop-legs suggesting the
loop-tops are not sites of enhanced turbulence. Line-of-sight speeds
in the loop arcade are typically <10 km s<SUP>-1</SUP>, and mean
non-thermal motions fall from 43 km s<SUP>-1</SUP> at the flare peak
to 26 km s<SUP>-1</SUP> six minutes later. If the average velocity
in the loop arcade is assumed to be at rest, then it implies a new
reference wavelength for the Fe XXI line of 1354.106 ± 0.023 Å.
---------------------------------------------------------
Title: Venus' thermospheric temperature field using a refraction
model at terminator : comparison with 2012 transit observations
using SDO/HMI, VEx/SPICAV/SOIR and NSO/DST/FIRS
Authors: Widemann, Thomas; Jaeggli, Sarah; Reardon, Kevin; Tanga,
Paolo; Père, Christophe; Pasachoff, Jay M.; Vandaele, Ann Carine;
Wilquet, Valerie; Mahieux, Arnaud; Wilson, Colin
2014DPS....4630206W Altcode:
The transit of Venus in June 2012 provided a unique case study of the
Venus' atmosphere transiting in front of the Sun, while at the same time
ESA's Venus Express orbiter observed the evening terminator at solar
ingress and solar egress.We report on mesospheric temperature at Venus'
morning terminator using SDO/HMI aureole photometry and comparison with
Venus Express. Close to ingress and egress phases, we have shown that
the aureole photometry reflects the local density scale height and the
altitude of the refracting layer (Tanga et al. 2012). The lightcurve of
each spatially resolved aureole element is fit to a two-parameter model
to constrain the meridional temperature gradient at terminator. Our
measurements are in agreement with the VEx/SOIR temperatures obtained
during orbit 2238 at evening terminator during solar ingress (46.75N -
LST = 6.075PM) and solar egress (31.30N - LST = 6.047PM) captured from
the Venus Express orbiter at the time Venus transited the Sun.We also
performed spectroscopy and polarimetry during the transit of Venus
focusing on extracting signatures of CO2 absorption. Observations were
taken during the first half of the transit using the Facility InfraRed
Spectropolarimeter (FIRS) on the Dunn Solar Telescope (DST). Although
the predicted CO2 transmission spectrum of Venus was not particularly
strong at 1565 nm, this region of the H-band often used in magnetic
field studies of the Sun's photosphere provides a particularly flat
solar continuum with few atmospheric lines. Sun-subtracted Venus limb
observations show intensity distribution of vibrational CO2 bands 221
2v+2v2+v3 at 1.571μm and 141 v1+4v2+v3 at 1.606μm.
---------------------------------------------------------
Title: Hot explosions in the cool atmosphere of the Sun
Authors: Peter, H.; Tian, H.; Curdt, W.; Schmit, D.; Innes, D.;
De Pontieu, B.; Lemen, J.; Title, A.; Boerner, P.; Hurlburt, N.;
Tarbell, T. D.; Wuelser, J. P.; Martínez-Sykora, Juan; Kleint,
L.; Golub, L.; McKillop, S.; Reeves, K. K.; Saar, S.; Testa, P.;
Kankelborg, C.; Jaeggli, S.; Carlsson, M.; Hansteen, V.
2014Sci...346C.315P Altcode: 2014arXiv1410.5842P
The solar atmosphere was traditionally represented with a simple
one-dimensional model. Over the past few decades, this paradigm shifted
for the chromosphere and corona that constitute the outer atmosphere,
which is now considered a dynamic structured envelope. Recent
observations by the Interface Region Imaging Spectrograph (IRIS) reveal
that it is difficult to determine what is up and down, even in the cool
6000-kelvin photosphere just above the solar surface: This region hosts
pockets of hot plasma transiently heated to almost 100,000 kelvin. The
energy to heat and accelerate the plasma requires a considerable
fraction of the energy from flares, the largest solar disruptions. These
IRIS observations not only confirm that the photosphere is more complex
than conventionally thought, but also provide insight into the energy
conversion in the process of magnetic reconnection.
---------------------------------------------------------
Title: The unresolved fine structure resolved: IRIS observations of
the solar transition region
Authors: Hansteen, V.; De Pontieu, B.; Carlsson, M.; Lemen, J.; Title,
A.; Boerner, P.; Hurlburt, N.; Tarbell, T. D.; Wuelser, J. P.; Pereira,
T. M. D.; De Luca, E. E.; Golub, L.; McKillop, S.; Reeves, K.; Saar,
S.; Testa, P.; Tian, H.; Kankelborg, C.; Jaeggli, S.; Kleint, L.;
Martínez-Sykora, J.
2014Sci...346E.315H Altcode: 2014arXiv1412.3611H
The heating of the outer solar atmospheric layers, i.e., the transition
region and corona, to high temperatures is a long-standing problem
in solar (and stellar) physics. Solutions have been hampered by an
incomplete understanding of the magnetically controlled structure of
these regions. The high spatial and temporal resolution observations
with the Interface Region Imaging Spectrograph (IRIS) at the solar
limb reveal a plethora of short, low-lying loops or loop segments
at transition-region temperatures that vary rapidly, on the time
scales of minutes. We argue that the existence of these loops solves
a long-standing observational mystery. At the same time, based on
comparison with numerical models, this detection sheds light on a
critical piece of the coronal heating puzzle.
---------------------------------------------------------
Title: Evidence of nonthermal particles in coronal loops heated
impulsively by nanoflares
Authors: Testa, P.; De Pontieu, B.; Allred, J.; Carlsson, M.; Reale,
F.; Daw, A.; Hansteen, V.; Martinez-Sykora, J.; Liu, W.; DeLuca, E. E.;
Golub, L.; McKillop, S.; Reeves, K.; Saar, S.; Tian, H.; Lemen, J.;
Title, A.; Boerner, P.; Hurlburt, N.; Tarbell, T. D.; Wuelser, J. P.;
Kleint, L.; Kankelborg, C.; Jaeggli, S.
2014Sci...346B.315T Altcode: 2014arXiv1410.6130T
The physical processes causing energy exchange between the Sun’s
hot corona and its cool lower atmosphere remain poorly understood. The
chromosphere and transition region (TR) form an interface region between
the surface and the corona that is highly sensitive to the coronal
heating mechanism. High-resolution observations with the Interface
Region Imaging Spectrograph (IRIS) reveal rapid variability (~20 to
60 seconds) of intensity and velocity on small spatial scales (≲500
kilometers) at the footpoints of hot and dynamic coronal loops. The
observations are consistent with numerical simulations of heating by
beams of nonthermal electrons, which are generated in small impulsive
(≲30 seconds) heating events called “coronal nanoflares.” The
accelerated electrons deposit a sizable fraction of their energy
(≲10<SUP>25 </SUP>erg) in the chromosphere and TR. Our analysis
provides tight constraints on the properties of such electron beams
and new diagnostics for their presence in the nonflaring corona.
---------------------------------------------------------
Title: Prevalence of small-scale jets from the networks of the solar
transition region and chromosphere
Authors: Tian, H.; DeLuca, E. E.; Cranmer, S. R.; De Pontieu, B.;
Peter, H.; Martínez-Sykora, J.; Golub, L.; McKillop, S.; Reeves,
K. K.; Miralles, M. P.; McCauley, P.; Saar, S.; Testa, P.; Weber,
M.; Murphy, N.; Lemen, J.; Title, A.; Boerner, P.; Hurlburt, N.;
Tarbell, T. D.; Wuelser, J. P.; Kleint, L.; Kankelborg, C.; Jaeggli,
S.; Carlsson, M.; Hansteen, V.; McIntosh, S. W.
2014Sci...346A.315T Altcode: 2014arXiv1410.6143T
As the interface between the Sun’s photosphere and corona, the
chromosphere and transition region play a key role in the formation and
acceleration of the solar wind. Observations from the Interface Region
Imaging Spectrograph reveal the prevalence of intermittent small-scale
jets with speeds of 80 to 250 kilometers per second from the narrow
bright network lanes of this interface region. These jets have lifetimes
of 20 to 80 seconds and widths of ≤300 kilometers. They originate from
small-scale bright regions, often preceded by footpoint brightenings
and accompanied by transverse waves with amplitudes of ~20 kilometers
per second. Many jets reach temperatures of at least ~10<SUP>5</SUP>
kelvin and constitute an important element of the transition region
structures. They are likely an intermittent but persistent source of
mass and energy for the solar wind.
---------------------------------------------------------
Title: On the prevalence of small-scale twist in the solar
chromosphere and transition region
Authors: De Pontieu, B.; Rouppe van der Voort, L.; McIntosh, S. W.;
Pereira, T. M. D.; Carlsson, M.; Hansteen, V.; Skogsrud, H.; Lemen,
J.; Title, A.; Boerner, P.; Hurlburt, N.; Tarbell, T. D.; Wuelser,
J. P.; De Luca, E. E.; Golub, L.; McKillop, S.; Reeves, K.; Saar,
S.; Testa, P.; Tian, H.; Kankelborg, C.; Jaeggli, S.; Kleint, L.;
Martinez-Sykora, J.
2014Sci...346D.315D Altcode: 2014arXiv1410.6862D
The solar chromosphere and transition region (TR) form an interface
between the Sun’s surface and its hot outer atmosphere. There,
most of the nonthermal energy that powers the solar atmosphere
is transformed into heat, although the detailed mechanism remains
elusive. High-resolution (0.33-arc second) observations with NASA’s
Interface Region Imaging Spectrograph (IRIS) reveal a chromosphere
and TR that are replete with twist or torsional motions on sub-arc
second scales, occurring in active regions, quiet Sun regions, and
coronal holes alike. We coordinated observations with the Swedish
1-meter Solar Telescope (SST) to quantify these twisting motions and
their association with rapid heating to at least TR temperatures. This
view of the interface region provides insight into what heats the low
solar atmosphere.
---------------------------------------------------------
Title: An Interface Region Imaging Spectrograph First View on Solar
Spicules
Authors: Pereira, T. M. D.; De Pontieu, B.; Carlsson, M.; Hansteen,
V.; Tarbell, T. D.; Lemen, J.; Title, A.; Boerner, P.; Hurlburt,
N.; Wülser, J. P.; Martínez-Sykora, J.; Kleint, L.; Golub, L.;
McKillop, S.; Reeves, K. K.; Saar, S.; Testa, P.; Tian, H.; Jaeggli,
S.; Kankelborg, C.
2014ApJ...792L..15P Altcode: 2014arXiv1407.6360P
Solar spicules have eluded modelers and observers for decades. Since
the discovery of the more energetic type II, spicules have become
a heated topic but their contribution to the energy balance of the
low solar atmosphere remains unknown. Here we give a first glimpse of
what quiet-Sun spicules look like when observed with NASA's recently
launched Interface Region Imaging Spectrograph (IRIS). Using IRIS
spectra and filtergrams that sample the chromosphere and transition
region, we compare the properties and evolution of spicules as
observed in a coordinated campaign with Hinode and the Atmospheric
Imaging Assembly. Our IRIS observations allow us to follow the thermal
evolution of type II spicules and finally confirm that the fading
of Ca II H spicules appears to be caused by rapid heating to higher
temperatures. The IRIS spicules do not fade but continue evolving,
reaching higher and falling back down after 500-800 s. Ca II H type
II spicules are thus the initial stages of violent and hotter events
that mostly remain invisible in Ca II H filtergrams. These events
have very different properties from type I spicules, which show lower
velocities and no fading from chromospheric passbands. The IRIS spectra
of spicules show the same signature as their proposed disk counterparts,
reinforcing earlier work. Spectroheliograms from spectral rasters also
confirm that quiet-Sun spicules originate in bushes from the magnetic
network. Our results suggest that type II spicules are indeed the
site of vigorous heating (to at least transition region temperatures)
along extensive parts of the upward moving spicular plasma.
---------------------------------------------------------
Title: Molecular absorption in transition region spectral lines
Authors: Schmit, D. J.; Innes, D.; Ayres, T.; Peter, H.; Curdt, W.;
Jaeggli, S.
2014A&A...569L...7S Altcode: 2014arXiv1409.1702S
<BR /> Aims: We present observations from the Interface Region Imaging
Spectrograph (IRIS) of absorption features from a multitude of cool
atomic and molecular lines within the profiles of Si IV transition
region lines. Many of these spectral lines have not previously
been detected in solar spectra. <BR /> Methods: We examined spectra
taken from deep exposures of plage on 12 October 2013. We observed
unique absorption spectra over a magnetic element which is bright in
transition region line emission and the ultraviolet continuum. We
compared the absorption spectra with emission spectra that is
likely related to fluorescence. <BR /> Results: The absorption
features require a population of sub-5000 K plasma to exist above
the transition region. This peculiar stratification is an extreme
deviation from the canonical structure of the chromosphere-corona
boundary. The cool material is not associated with a filament or
discernible coronal rain. This suggests that molecules may form in
the upper solar atmosphere on small spatial scales and introduces a
new complexity into our understanding of solar thermal structure. It
lends credence to previous numerical studies that found evidence
for elevated pockets of cool gas in the chromosphere. <P />Movies
associated to Figs. 1 and 2 are available in electronic form at <A
href="http://www.aanda.org/10.1051/0004-6361/201424432/olm">http://www.aanda.org</A>
---------------------------------------------------------
Title: The Interface Region Imaging Spectrograph (IRIS)
Authors: De Pontieu, B.; Title, A. M.; Lemen, J. R.; Kushner, G. D.;
Akin, D. J.; Allard, B.; Berger, T.; Boerner, P.; Cheung, M.; Chou,
C.; Drake, J. F.; Duncan, D. W.; Freeland, S.; Heyman, G. F.; Hoffman,
C.; Hurlburt, N. E.; Lindgren, R. W.; Mathur, D.; Rehse, R.; Sabolish,
D.; Seguin, R.; Schrijver, C. J.; Tarbell, T. D.; Wülser, J. -P.;
Wolfson, C. J.; Yanari, C.; Mudge, J.; Nguyen-Phuc, N.; Timmons,
R.; van Bezooijen, R.; Weingrod, I.; Brookner, R.; Butcher, G.;
Dougherty, B.; Eder, J.; Knagenhjelm, V.; Larsen, S.; Mansir, D.;
Phan, L.; Boyle, P.; Cheimets, P. N.; DeLuca, E. E.; Golub, L.;
Gates, R.; Hertz, E.; McKillop, S.; Park, S.; Perry, T.; Podgorski,
W. A.; Reeves, K.; Saar, S.; Testa, P.; Tian, H.; Weber, M.; Dunn, C.;
Eccles, S.; Jaeggli, S. A.; Kankelborg, C. C.; Mashburn, K.; Pust, N.;
Springer, L.; Carvalho, R.; Kleint, L.; Marmie, J.; Mazmanian, E.;
Pereira, T. M. D.; Sawyer, S.; Strong, J.; Worden, S. P.; Carlsson,
M.; Hansteen, V. H.; Leenaarts, J.; Wiesmann, M.; Aloise, J.; Chu,
K. -C.; Bush, R. I.; Scherrer, P. H.; Brekke, P.; Martinez-Sykora,
J.; Lites, B. W.; McIntosh, S. W.; Uitenbroek, H.; Okamoto, T. J.;
Gummin, M. A.; Auker, G.; Jerram, P.; Pool, P.; Waltham, N.
2014SoPh..289.2733D Altcode: 2014arXiv1401.2491D; 2014SoPh..tmp...25D
The Interface Region Imaging Spectrograph (IRIS) small explorer
spacecraft provides simultaneous spectra and images of the photosphere,
chromosphere, transition region, and corona with 0.33 - 0.4 arcsec
spatial resolution, two-second temporal resolution, and 1 km
s<SUP>−1</SUP> velocity resolution over a field-of-view of up to
175 arcsec × 175 arcsec. IRIS was launched into a Sun-synchronous
orbit on 27 June 2013 using a Pegasus-XL rocket and consists of a
19-cm UV telescope that feeds a slit-based dual-bandpass imaging
spectrograph. IRIS obtains spectra in passbands from 1332 - 1358 Å,
1389 - 1407 Å, and 2783 - 2834 Å, including bright spectral lines
formed in the chromosphere (Mg II h 2803 Å and Mg II k 2796 Å) and
transition region (C II 1334/1335 Å and Si IV 1394/1403 Å). Slit-jaw
images in four different passbands (C II 1330, Si IV 1400, Mg II k
2796, and Mg II wing 2830 Å) can be taken simultaneously with spectral
rasters that sample regions up to 130 arcsec × 175 arcsec at a variety
of spatial samplings (from 0.33 arcsec and up). IRIS is sensitive to
emission from plasma at temperatures between 5000 K and 10 MK and will
advance our understanding of the flow of mass and energy through an
interface region, formed by the chromosphere and transition region,
between the photosphere and corona. This highly structured and dynamic
region not only acts as the conduit of all mass and energy feeding
into the corona and solar wind, it also requires an order of magnitude
more energy to heat than the corona and solar wind combined. The
IRIS investigation includes a strong numerical modeling component
based on advanced radiative-MHD codes to facilitate interpretation of
observations of this complex region. Approximately eight Gbytes of data
(after compression) are acquired by IRIS each day and made available
for unrestricted use within a few days of the observation.
---------------------------------------------------------
Title: Detection of Supersonic Downflows and Associated Heating
Events in the Transition Region above Sunspots
Authors: Kleint, L.; Antolin, P.; Tian, H.; Judge, P.; Testa, P.;
De Pontieu, B.; Martínez-Sykora, J.; Reeves, K. K.; Wuelser, J. P.;
McKillop, S.; Saar, S.; Carlsson, M.; Boerner, P.; Hurlburt, N.; Lemen,
J.; Tarbell, T. D.; Title, A.; Golub, L.; Hansteen, V.; Jaeggli, S.;
Kankelborg, C.
2014ApJ...789L..42K Altcode: 2014arXiv1406.6816K
Interface Region Imaging Spectrograph data allow us to study the solar
transition region (TR) with an unprecedented spatial resolution of
0.”33. On 2013 August 30, we observed bursts of high Doppler shifts
suggesting strong supersonic downflows of up to 200 km s<SUP>-1</SUP>
and weaker, slightly slower upflows in the spectral lines Mg II h
and k, C II 1336, Si IV 1394 Å, and 1403 Å, that are correlated
with brightenings in the slitjaw images (SJIs). The bursty behavior
lasts throughout the 2 hr observation, with average burst durations
of about 20 s. The locations of these short-lived events appear to
be the umbral and penumbral footpoints of EUV loops. Fast apparent
downflows are observed along these loops in the SJIs and in the
Atmospheric Imaging Assembly, suggesting that the loops are thermally
unstable. We interpret the observations as cool material falling
from coronal heights, and especially coronal rain produced along the
thermally unstable loops, which leads to an increase of intensity
at the loop footpoints, probably indicating an increase of density
and temperature in the TR. The rain speeds are on the higher end of
previously reported speeds for this phenomenon, and possibly higher
than the free-fall velocity along the loops. On other observing days,
similar bright dots are sometimes aligned into ribbons, resembling
small flare ribbons. These observations provide a first insight into
small-scale heating events in sunspots in the TR.
---------------------------------------------------------
Title: Chromospheric Diagnostics from IRIS and DST
Authors: Cauzzi, Gianna; Reardon, Kevin P.; Jaeggli, Sarah A.;
Reid, Aaron
2014AAS...22430201C Altcode:
Using data obtained during a coordinated observing campaign in
September 2013, we compare the spectral and imaging diagnostics from
IRIS and the instruments at the Dunn Solar Telescope (DST). We focus
on a small active region observed for approximately one hour with IRIS
(NUV, FUV, and SJI) in conjunction with IBIS, FIRS, and ROSA from the
DST.In particular, we examine the line widths and intensities in the
different chromospheric lines (H-alpha, Ca II 8542, Mg II) and the
temporal evolution of these different diagnostics. This allows us to
better relate the views from new window provided by IRIS to previous
studies of the chromosphere.
---------------------------------------------------------
Title: Investigating Molecular Hydrogen in Active Regions with IRIS
Authors: Jaeggli, Sarah A.; Saar, Steven H.; Daw, Adrian N.; Innes,
Davina
2014AAS...22432306J Altcode:
Molecular hydrogen should be the most abundant molecular species in
sunspots, but recent observations with IRIS show that its florescent
signature is absent from above the sunspot umbra, but appears
brightly during flares. In this poster we continue the analysis of
FUV observations of H2 in active regions, examining the correlation
between the intensity of the H2 lines and the lines of C II and
Si IV which are responsible for their excitation. We particularly
focus on differentiating places where H2 is abundant, holes in the
chromospheric opacity where FUV photons can enter more deeply into the
solar atmosphere, and places where the FUV radiation field is intense,
as in flares.
---------------------------------------------------------
Title: H2 Emission in the Sun and Stars: A New Window on Spots
and Flares
Authors: Saar, Steven H.; Jaeggli, Sarah A.
2014AAS...22412344S Altcode:
Molecular H2 is likely important for the formation of sun and starspots,
but has been difficult to observe in the past. H2 emission has been
seen in solar FUV spectra of sunspots and flares, where it produced
by fluorescent excitation driven (primarily) by Si IV and O IV. New
observations with IRIS show that the emission is strong in flares,
and in loops connected to pores or the boundaries of umbrae. We find
evidence for H2 emission in the HST spectra of several magnetically
active, flaring, spotted stars. Once the excitation process is better
understood, observations of H2 emission should permit new insight into
spot formation on the Sun and active stars.
---------------------------------------------------------
Title: Venus' thermospheric temperature field using a refraction
model at terminator : comparison with 2012 transit observations
using SDO/HMI and NSO/DST/FIRS
Authors: Widemann, Thomas; Tanga, Paolo; Père, Christophe; Jaeggli,
Sarah; Reardon, Kevin; Pasachoff, Jay M.
2014EGUGA..1612916W Altcode:
The transit of Venus in June 2012 provided a unique case study of an
Earth-size planet's atmosphere transiting in front of its parent star
at 0.7AU, while at the same time ESA's Venus Express orbiter observed
the evening terminator at solar ingress and solar egress. We report
on mesospheric temperature at Venus' morning terminator using SDO/HMI
aureole photometry and comparison with Venus Express. Close to ingress
and egress phases, we have shown that the aureole photometry reflects
the local density scale height and the altitude of the refracting layer
(Tanga et al. 2012). The lightcurve of each spatial resolution element
of the aureole is compared to a two-parameter model to constrain the
meridional temperature gradient along the terminator. Our measurements
are in agreement with the VEx/SOIR temperatures obtained during
orbit 2238 at evening terminator during solar ingress (46.75N - LST
= 6.075PM) and solar egress (31.30N - LST = 6.047PM) captured from
the Venus Express orbiter at the time Venus transited the Sun for
Earth-based observers. We also performed spectroscopy and polarimetry
during the transit of Venus focusing on extracting signatures of
CO2 absorption. Observations were taken during the first half of the
transit using the Facility InfraRed Spectropolarimeter on the Dunn
Solar Telescope. Although the predicted CO2 transmission spectrum
of Venus was not particularly strong at 1565 nm, this region of the
H-band often used in magnetic field studies of the Sun's photosphere
provides a particularly flat solar continuum with few atmospheric and
molecular lines. Sun-subtracted Venus limb observations show intensity
distribution of vibrational CO2 bands 221 2v + 2ν2 + ν3 at 1.571um and
141 ν1 + 4ν2 + ν3 at 1.606um. Data independently allow to constrain
temperature as well as cross-terminator thermospheric winds.
---------------------------------------------------------
Title: High-resolution Observations of the Shock Wave Behavior for
Sunspot Oscillations with the Interface Region Imaging Spectrograph
Authors: Tian, H.; DeLuca, E.; Reeves, K. K.; McKillop, S.; De Pontieu,
B.; Martínez-Sykora, J.; Carlsson, M.; Hansteen, V.; Kleint, L.;
Cheung, M.; Golub, L.; Saar, S.; Testa, P.; Weber, M.; Lemen, J.;
Title, A.; Boerner, P.; Hurlburt, N.; Tarbell, T. D.; Wuelser, J. P.;
Kankelborg, C.; Jaeggli, S.; McIntosh, S. W.
2014ApJ...786..137T Altcode: 2014arXiv1404.6291T
We present the first results of sunspot oscillations from observations
by the Interface Region Imaging Spectrograph. The strongly nonlinear
oscillation is identified in both the slit-jaw images and the
spectra of several emission lines formed in the transition region and
chromosphere. We first apply a single Gaussian fit to the profiles of
the Mg II 2796.35 Å, C II 1335.71 Å, and Si IV 1393.76 Å lines in the
sunspot. The intensity change is ~30%. The Doppler shift oscillation
reveals a sawtooth pattern with an amplitude of ~10 km s<SUP>-1</SUP>
in Si IV. The Si IV oscillation lags those of C II and Mg II by ~3 and
~12 s, respectively. The line width suddenly increases as the Doppler
shift changes from redshift to blueshift. However, we demonstrate
that this increase is caused by the superposition of two emission
components. We then perform detailed analysis of the line profiles at
a few selected locations on the slit. The temporal evolution of the
line core is dominated by the following behavior: a rapid excursion
to the blue side, accompanied by an intensity increase, followed by a
linear decrease of the velocity to the red side. The maximum intensity
slightly lags the maximum blueshift in Si IV, whereas the intensity
enhancement slightly precedes the maximum blueshift in Mg II. We find
a positive correlation between the maximum velocity and deceleration,
a result that is consistent with numerical simulations of upward
propagating magnetoacoustic shock waves.
---------------------------------------------------------
Title: Characterization of a transiting exo-Venus : lessons from
the 2012 Transit
Authors: Widemann, Thomas; Jaeggli, S. A.; Reardon, K. P.; Tanga,
P.; Pasachoff, J. M.; Schneider, G.
2013DPS....4511811W Altcode:
The transit of Venus in June 2012 provided a unique chance to
view a well studied planetary atmosphere as we might see that of a
transiting exoplanet, through scattered and refracted illumination
of its parent star. We report on mesospheric temperature at Venus'
morning terminator using SDO/HMI aureole photometry and comparison with
Venus Express. Close to ingress and egress phases, we have shown that
the aureole photometry reflects the local density scale height and the
altitude of the refracting layer (Tanga et al. 2012). The lightcurve
of each spatial resolution element of the aureole is compared to a
two-parameter model to constrain the meridional temperature gradient
along the terminator. Our measurements are in agreement with the
VEx/SOIR temperatures obtained during orbit 2238 at evening terminator
during solar ingress (46.75N - LST = 6.075PM) and solar egress (31.30N -
LST = 6.047PM) as seen from the orbiter. Imaging data using IBIS/ROSA on
the Dunn Solar Telescope in the G-band (430 nm) are also presented. We
also performed spectroscopy and polarimetry during the transit of Venus
focusing on extracting signatures of CO2 absorption. Observations were
taken during the first half of the transit using the Facility InfraRed
Spectropolarimeter on the Dunn Solar Telescope. Although the predicted
CO2 transmission spectrum of Venus was not particularly strong at 1565
nm, this region of the H-band often used in magnetic field studies of
the Sun's photosphere provides a particularly flat solar continuum
with few atmospheric and molecular lines. Sun-subtracted Venus limb
observations show intensity distribution of vibro-rotational CO2 band
221 2ν + 2ν2 + ν3 at 1.571μm allowing for an additional constraint
on Venus' thermospheric temperature.
---------------------------------------------------------
Title: Testing Milne-Eddington Inversion Codes Against One-Dimensional
Model Atmospheres
Authors: Lastufka, Erica; Jaeggli, S. A.; Kankelborg, C.; Uitenbroek,
H.
2013SPD....44..116L Altcode:
Properties of solar vector magnetic fields can be determined by the
inversion of polarization spectra. It is therefore important to have
accurate inversion methods. Milne-Eddington inversions, used almost
exclusively in the photosphere, assume a thin, flat atmosphere and are
one of the most widely used inversion techniques. To investigate the
potential weaknesses of parameterizing a stratified atmosphere using
a single set of properties, we examine the consequences of using a
Milne-Eddington inversion to invert spectra of complex atmospheres. Han
Uitenbroek's Rybicki-Hummer radiative transfer and chemical equilibrium
code was used to generate a series of one-dimensional model atmospheres
with predetermined magnetic field configurations. Atmospheres at the
quiet Sun temperature contained magnetic fields with strengths up
3000 G and inclination and azimuthal angles from 0 to 180 degrees. We
examined the Stokes profiles of the Fe 15648.5 line, which with a
Landé g-factor of 3.0 is very sensitive to the magnetic field. Using a
simple Milne-Eddington inversion code, we examined the ranges in which
the code accurately parameterized the magnetic field. To investigate
the confidence intervals associated with the inverted parameters, we
used the BayesME code developed by Andres Asensio Ramos. We discuss
the key assumptions and limitations of a Milne-Eddington inversion.
---------------------------------------------------------
Title: Supernova 2013do in UGC 12137 = Psn J22395067+3812443
Authors: Elenin, L.; Molotov, I.; Rachubo, A. A.; Leonard, D. C.;
Follette, K.; Sheehan, P.; McCarthy, D.; Moustakas, J.; Bailey, V.;
Barrows, J.; Bosset, E.; Buckley, E.; Burd, D.; Calahan, J.; Ceesay,
I.; Douglas, E.; Feeney, C.; Fornari, T.; Fox, A.; Fishwick, H.;
Gano, H.; Green, C.; Griggs, J.; Hart, K.; Hart, S.; Hartman, K.;
Holt, A.; Hooper, E.; Hume, S.; Jaeggli, S.; Lesser, D.; Kerr, M.;
Kopans-Johnson, C.; Kumar, K.; Lackey, A.; Laube, S.; Marshall, E.;
Martinez, M.; Mehta, G.; Melbourne, K.; Meshel, M.; Myers, C.; Puranen,
E.; Schlingman, A.; Shen, K.; Stock, N.; Stillman, C.; Tinker, J.;
Whitesell, B.; Tinyanont, S.; Cao, Y.; Kasliwal, M. M.
2013CBET.3571....2E Altcode:
Additional CCD magnitudes for 2013do: 2013 June 1, [19.0
(Wang and Gao); 17.763, 17.0 (Joseph Brimacombe, Cairns,
Australia; 41-cm telescope + infrared filter; bandpass >
700 nm; position end figures 50s.65, 43".5; image posted at URL
http://www.flickr.com/photos/43846774@N02/9074451038/); 18.253,
18.1 (L. Elenin, Lyubertsy, Russia, and I. Molotov, Moscow;
three 150-s images taken remotely with a 0.45-m f/2.8 telescope
at the ISON-NM Observatory near Mayhill, NM, USA; position end
figures 50s.54 +/- 0".18, 44".8 +/- 0".19; UCAC-4 reference
stars; limiting mag about 18.8; image posted at website URL
http://spaceobs.org/images/TOCP/PSNJ22395067+3812443-20130618.png);
21.832, 17.2 (Wang and Gao; position end figures 50s.69, 44".3); 22.819,
17.1 (Wang and Gao; position end figures 50s.70, 43".3). A. A. Rachubo
and D. C. Leonard, San Diego State University; K. Follette, P. Sheehan,
and D. McCarthy, University of Arizona; J. Moustakas, Siena College;
V. Bailey, J. Barrows, E. Bosset, E. Buckley, D. Burd, J. Calahan,
I. Ceesay, E. Douglas, C. Feeney, T. Fornari, A. Fox, H. Fishwick,
H. Gano, C. Green, J. Griggs, K. Hart, S. Hart, K. Hartman, A. Holt,
E. Hooper, S. Hume, S. Jaeggli, D. Lesser, M. Kerr, C. Kopans-Johnson,
K. Kumar, A. Lackey, S. Laube, E. Marshall, M. Martinez, G. Mehta,
K. Melbourne, M. Meshel, C. Myers, E. Puranen, A. Schlingman,
W. Schlingman, W. M. Schlingman, K. Shen, N. Stock, C. Stillman,
J. Tinker, and B. Whitesell, 2013 Advanced Teen Astronomy Camp, report
that inspection of a low-dispersion optical spectrum (range 350-660
nm) of PSN J22395067+3812443 = SN 2013do, obtained with the 2.3-m Bok
telescope (+ Boller & Chivens spectrograph) at Steward Observatory
on June 26 UT, shows it to be a type-II supernova. Cross-correlation
with a library of supernova spectra using the "Supernova Identification"
code (SNID; Blondin and Tonry 2007, Ap.J. 666, 1024) finds best matches
with a number of normal type-IIP supernovae ranging in age from about
one to two weeks after maximum light. Adopting the recession velocity
for UGC 12137 of 4685 km/s (Wegner et al. 1993, A.J. 105, 1251; via
the NASA/IPAC Extragalactic Database), an expansion velocity of 8900
km/s is derived from the position of the H_beta (rest wavelength 486.1
nm) minimum. S. Tinyanont, Harvey Mudd College; Y. Cao, California
Institute of Technology; and M. M. Kasliwal, Observatories of the
Carnegie Institution and Princeton University, report that spectroscopic
observations (range 330-1000 nm) of PSN J22395067+3812443 = SN 2013do
were obtained on June 27.27 UT with the Dual Imaging Spectrograph on
the 3.5-m ARC telescope at Apache Point Observatory. The spectrum
shows prominent H-alpha emission with a P-Cyg profile. The minimum
of the H-alpha absorption is at 642.5 nm. Using the redshift z =
0.015627 for UGC 12137 (from Wegner et al. 1993, A.J. 105, 1251;
via NED), this corresponds to a velocity of 11000 km/s. Running the
SNID software, the spectrum resembles SN 2004et at fifteen days after
maximum, indicating that 2013do is a type-II-P supernova.
---------------------------------------------------------
Title: Supernova 2013dq in UGC 525 = Psn J00513484+2943149
Authors: Howerton, S.; Drake, A. J.; Djorgovski, S. G.; Mahabal, A.;
Graham, M. J.; Williams, R.; Prieto, J. L.; Catelan, M.; Christensen,
E.; Larson, S. M.; Rachubo, A. A.; Leonard, D. C.; Follette, K.;
Sheehan, P.; Bailey, V.; McCarthy, D.; Moustakas, J.; Barrows, J.;
Bosset, E.; Buckley, E.; Burd, D.; Calahan, J.; Ceesay, I.; Douglas,
E.; Feeney, C.; Fornari, T.; Fox, A.; Fishwick, H.; Gano, H.; Green,
C.; Griggs, J.; Hart, K.; Hart, S.; Hartman, K.; Holt, A.; Hooper,
E.; Hume, S.; Jaeggli, S.; Lesser, D.; Kerr, M.; Kopans-Johnson, C.;
Kumar, K.; Lackey, A.; Laube, S.; Marshall, E.; Martinez, M.; Mehta,
G.; Melbourne, K.; Meshel, M.; Myers, C.; Puranen, E.; Schlingman,
A.; Shen, K.; Stock, N.; Stillman, C.; Tinker, J.; Whitesell, B.
2013CBET.3573....1H Altcode: 2013CBET.3573A...1H
S. Howerton, Arkansas City, KS, U.S.A.; A. J. Drake, S. G. Djorgovski,
A. Mahabal, M. J. Graham, and R. Williams, California Institute
of Technology; J. L. Prieto, Princeton University; M. Catelan,
Pontificia Universidad Catolica de Chile; and E. Christensen and
S. M. Larson, Lunar and Planetary Laboratory, University of Arizona,
report the Catalina Real-time Transient Survey discovery of an
apparent supernova in public images from the Catalina Sky Survey
(CSS). SN 2013 UT R.A. (2000.0) Decl. Mag. Offset 2013dq June 27.44 0
51 34.84 +29 43 14.9 16.8 4".3 E, 15".6 N The variable was designated
PSN J00513484+2943149 when it was posted at the Central Bureau's TOCP
webpage and is here designated SN 2013dq based on the spectroscopic
confirmation reported below. Additional CCD magnitudes for 2013dq:
Feb. 8.14 UT, [19.5 (CSS); June 28.814, 17.2 (Joseph Brimacombe,
Cairns, Australia; 41-cm telescope + infrared filter; bandpass >
700 nm; position end figures 35s.02, 13".8; image posted at website URL
http://www.flickr.com/photos/43846774@N02/9174594184/). A. A. Rachubo
and D. C. Leonard, San Diego State University; K. Follette, P. Sheehan,
V. Bailey, and D. McCarthy, University of Arizona; J. Moustakas,
Siena College; J. Barrows, E. Bosset, E. Buckley, D. Burd, J. Calahan,
I. Ceesay, E. Douglas, C. Feeney, T. Fornari, A. Fox, H. Fishwick,
H. Gano, C. Green, J. Griggs, K. Hart, S. Hart, K. Hartman, A. Holt,
E. Hooper, S. Hume, S. Jaeggli, D. Lesser, M. Kerr, C. Kopans-Johnson,
K. Kumar, A. Lackey, S. Laube, E. Marshall, M. Martinez, G. Mehta,
K. Melbourne, M. Meshel, C. Myers, E. Puranen, A. Schlingman,
W. Schlingman, W. M. Schlingman, K. Shen, N. Stock, C. Stillman,
J. Tinker, and B. Whitesell, 2013 Advanced Teen Astronomy Camp, report
that inspection of a low-dispersion optical spectrogram (range 370-680
nm) of PSN J00513484+2943149 = SN 2013dq, obtained in heavy twilight
with the 2.3-m Bok telescope (+ Boller & Chivens spectrograph)
at Steward Observatory on June 28 UT, shows it to be an aging type-Ia
supernova. After correcting for a redshift of 4931 km/s for the assumed
host galaxy, UGC 525 (Falco et al. 1999, PASP 111, 438; via NED),
reasonable matches are found with normal type-Ia supernovae at epochs
ranging between 40 and 65 days after maximum light, although there
is a notable absence of emission in 2013dq near 500.0 nm (attributed
to Fe II; Branch et al. 2008, PASP 120, 135) that is usually seen
at this phase. The most convincing individual spectral match is made
with SN 1999gp at 50 days post-maximum (Matheson et al. 2008, A.J. 135,
1598), which exhibited a broad, 1991T-like light-curve (dm15[B] = 0.80;
Hicken et al. 2009, Ap.J. 700, 331), a "shallow silicon" maximum-light
spectrum (Jha et al. 2000, IAUC 7341; Branch et al. 2009, PASP 121,
238), and somewhat-muted 500.0-nm emission at this phase.
---------------------------------------------------------
Title: 1565 nm Observations of the transit of Venus, Proxy for a
Transiting Exoplanet
Authors: Jaeggli, Sarah A.; Reardon, K. P.; Pasachoff, J. M.;
Schneider, G.; Widemann, T.; Tanga, P.
2013SPD....44..150J Altcode:
The transit of Venus in June 2012 provided a unique chance to view its
atmosphere as we might see that of a transiting Cytherean exoplanet,
through scattered and refracted illumination from its parent star. We
performed spectroscopy and polarimetry during the transit of Venus
focusing on extracting signatures of CO2 absorption of Venus from the
solar spectrum. Although the predicted CO2 transmission spectrum of
Venus was not particularly strong at 1565 nm, this region of the H-band
often used in magnetic-field studies of the Sun's photosphere provides
a particularly flat solar continuum with few atmospheric and molecular
lines. Observations of Venus were taken throughout first contact
and on the solar disk using the Facility InfraRed Spectropolarimeter
on the Dunn Solar Telescope at the National Solar Observatory. The
transit also provided a unique opportunity to investigate instrumental
effects. In this poster we discuss initial results from the transit,
including estimates for an exoplanet detection of this kind, preliminary
comparison with atmospheric models, and the stray light properties
of the instrument. This work was performed in collaboration with the
Williams College Venus transit expedition, which was sponsored by Natl
Geog/Comm for Research and Exploration.
---------------------------------------------------------
Title: National Student Solar Spectrograph Competition Overview
and Results
Authors: Des Jardins, Angela C.; Larimer, R.; Shaw, J. A.; Kankelborg,
C.; Palmer, C.; Key, J. S.; Nakagawa, W.; Springer, L.; Knighton,
W.; Repasky, K. S.; Pust, N. J.; Babbitt, W.; Jaeggli, S. A.; Hobish,
M. K.; Wilson, E. W.; Anderson, M.; Boger, J.; McCrady, N.; Naylor,
J.; Turcotte, S.; Lines, T.; Strobel, N.; Cooper, W.; Darke, R.; Head,
R.; Kimball, D.; Kissel, G.; Buck, K.; Lawrence, L.; Wragg, J.; Runyon,
C. J.; Spacher, P.; Dumitriu, I.; Nollenberg, J. G.; Estaban, R.
2013SPD....44..160D Altcode:
The yearly National Student Solar Spectrograph Competition (NSSSC)
is Montana Space Grant Consortium's Education and Public Outreach
(EP/O) Program for NASA's Interface Region Imaging Spectrograph (IRIS)
mission. The NSSSC is designed to give institutions with less aerospace
activity such as Minority Serving Institutions and Community Colleges
an opportunity for hands on real world research experience. The NSSSC
provides students from across the country the opportunity to work as
part of an undergraduate interdisciplinary team to design, build and
test a ground based solar spectrograph. Over the course of nine months,
teams come up with their own science goals and then build an instrument
to collect data in support of their goals. Teams then travel to Bozeman,
MT to demonstrate their instruments and present their results in a
competitive science fair environment. This poster will present the
2012-2013 competition results.Abstract (2,250 Maximum Characters):
The yearly National Student Solar Spectrograph Competition (NSSSC)
is Montana Space Grant Consortium's Education and Public Outreach
(EP/O) Program for NASA's Interface Region Imaging Spectrograph (IRIS)
mission. The NSSSC is designed to give institutions with less aerospace
activity such as Minority Serving Institutions and Community Colleges
an opportunity for hands on real world research experience. The NSSSC
provides students from across the country the opportunity to work as
part of an undergraduate interdisciplinary team to design, build and
test a ground based solar spectrograph. Over the course of nine months,
teams come up with their own science goals and then build an instrument
to collect data in support of their goals. Teams then travel to Bozeman,
MT to demonstrate their instruments and present their results in a
competitive science fair environment. This poster will present the
2012-2013 competition results.
---------------------------------------------------------
Title: Spectroscopy of PSN J00513484+2943149 in UGC 525
Authors: Rachubo, A. A.; Leonard, D. C.; Follette, K.; Sheehan, P.;
Bailey, V.; McCarthy, D.; Moustakas, J.; Barrows, J.; Bosset, E.;
Buckley, E.; Burd, D.; Calahan, J.; Ceesay, I.; Douglas, E.; Feeney,
C.; Fornari, T.; Fox, A.; Fishwick, H.; Gano, H.; Green, C.; Griggs,
J.; Hart, K.; Hart, S.; Hartman, K.; Holt, A.; Hooper, E.; Hume,
S.; Jaeggli, S.; Lesser, D.; Kerr, M.; Kopans-Johnson, C.; Kumar,
K.; Lackey, A.; Laube, S.; Marshall, E.; Martinez, M.; Mehta, G.;
Melbourne, K.; Meshel, M.; Myers, C.; Puranen, E.; Schlingman, A.;
Schlingman, W.; Schlingman, W. M.; Shen, K.; Stock, N.; Stillman,
C.; Tinker, J.; Whitesell, B.
2013ATel.5176....1R Altcode:
We report that inspection of a low-dispersion optical spectrum
(range 370-680 nm) of PSN J00513484+2943149 (CBAT TOCP), obtained in
heavy twilight with the 2.3-m Bok telescope (+ Boller & Chivens
spectrograph) at Steward Observatory on June 28 UT, shows it to be an
aging type-Ia supernova. After correcting for a redshift of 4931 km/s
for the assumed host galaxy, UGC 525 (Falco et al. 1999, PASP, 111,
438; via NED), reasonable matches are found with normal SNe Ia at
epochs ranging between 40 and 65 days after maximum light, although
there is a notable absence of emission in PSN J00513484+2943149 near
5000 Angstrom (attributed to Fe II; Branch et al.
---------------------------------------------------------
Title: Transit Observations of Venus's Atmosphere in 2012 from
Terrestrial and Space Telescopes as Exoplanet Analogs
Authors: Pasachoff, Jay M.; Schneider, G.; Babcock, B. A.; Lu, M.;
Penn, M. J.; Jaeggli, S. A.; Galayda, E.; Reardon, K. P.; Widemann,
T.; Tanga, P.; Ehrenreich, D.; Vidal-Madjar, A.; Nicholson, P. D.;
Dantowitz, R.
2013AAS...22221701P Altcode:
We extensively observed the 8 June 2012 transit of Venus from several
sites on Earth; we provide this interim status report about this and
about two subsequent ToVs observed from space. From Haleakala Obs., we
observed the entire June transit over almost 7 h with a coronagraph of
the Venus Twilight Experiment B filter) and with a RED Epic camera to
compare with simultaneous data from ESA's Venus Express, to study the
Cytherean mesosphere; from Kitt Peak, we have near-IR spectropolarimetry
at 1.6 µm from the aureole and during the disk crossing that compare
well with carbon dioxide spectral models; from Sac Peak/IBIS we have
high-resolution imaging of the Cytherean aureole for 22 min, starting
even before 1st contact; from Big Bear, we have high-resolution imaging
of Venus's atmosphere and the black-drop effect through 2nd contact;
and we had 8 other coronagraphs around the world. For the Sept 21 ToV
as seen from Jupiter, we had 14 orbits of HST to use Jupiter's clouds
as a reflecting surface to search for an 0.01% diminution in light and a
differential drop that would result from Venus's atmosphere by observing
in both IR/UV, for which we have 170 HST exposures. As of this writing,
preliminary data reduction indicates that variations in Jovian clouds
and the two periods of Jupiter's rotation will be too great to allow
extraction of the transit signal. For the December 20 ToV as seen from
Saturn, we had 22 hours of observing time with VIMS on Cassini, for
which we are looking for a signal of the 10-hr transit in total solar
irradiance and of Venus's atmosphere in IR as an exoplanet-transit
analog. Our Maui & Sac Peak expedition was sponsored by National
Geographic Society's Committee for Research and Exploration; HST data
reduction by NASA: HST-GO-13067. Some of the funds for the carbon
dioxide filter for Sac Peak provided by NASA through AAS's Small
Research Grant Program. We thank Rob Ratkowski of Haleakala Amateur
Astronomers; Rob Lucas, Aram Friedman, Eric Pilger, Stan Truitt,
and Steve Bisque/Software Bisque for Haleakala support/operations;
Vasyl Yurchyshyn and Joseph Gangestad '06 of The Aerospace Corp. at
Big Bear Solar Obs; LMSAL and Hinode science/operations team.
---------------------------------------------------------
Title: Multi-height Spectropolarimetry Of Sunspots With Firs And Ibis
Authors: Jaeggli, Sarah A.; Lin, H.; Tritschler, A.
2012AAS...22020606J Altcode:
The effects of radiative transfer prevent the characterization of
the magnetic field at a single geometric height in the photosphere
of a sunspot. Therefore, a full 3D characterization of the magnetic
field is necessary to understand many properties of sunspots, such as
the true state of hydrostatic equilibrium. Many current and proposed
solar spectropolarimeters are capable of taking near-simultaneous
observations at multiple wavelengths. Combining these rich datasets
provides a welcome problem to the community. We present the first joint
observations of the magnetically sensitive photospheric Fe I lines at
630 and 1565 nm taken with the Facility Infrared Spectropolarimeter
(FIRS); and the chromospheric Ca II line at 854 nm taken with the
Interferometric Bi-Dimensional Spectrometer (IBIS); both instruments
operated at the Dunn Solar Telescope. These wavelengths allow us to
probe the magnetic field over a broad range of heights, from the
bottom of the photosphere to the chromosphere. We investigate the
magnetic field topologies of several sunspots of different size and
magnetic complexity.
---------------------------------------------------------
Title: Comparison of Multi-Height Observations with a 3D MHD
Sunspot Model
Authors: Jaeggli, S. A.; Lin, H.; Uitenbroek, H.; Rempel, M.
2012ASPC..456...67J Altcode:
In sunspots the contribution to the horizontal pressure support from the
curvature force and the geometrical height of formation which magnetic
field measurements sample are poorly constrained observationally due to
the effect of radiative transfer. In cool atmospheres, observations of
the sunspot photosphere probe geometrically deeper layers, information
on the magnetic field gradients cannot be easily derived even using
multi-wavelength, multi-height observations. Recent MHD atmosphere
models of sunspots analyzed with the Rybiki-Hummer radiative transfer
code allow for direct comparison with simultaneous multi-height
observations of the Fe I magnetic field diagnostics at 1565 and 630.2
nm in sunspots observed using the Facility Infrared Spectropolarimeter
at the Dunn Solar Telescope.
---------------------------------------------------------
Title: Spies - Spectral Polarimetric Imager For The Energetic Sun
Authors: Lin, Haosheng; Jaeggli, S.
2012AAS...22012306L Altcode:
Spectropolarimetric observation with uncompromised spatial, spectral,
and temporal resolution simulatneously over a substantial 2D field and
multiple spectral lines is the key to the resolution of many important
questions in modern solar physics. While 2D imaging spectroscopy
based on fiber optics integral field unit and image slicer has a long
history nighttime astronomy, adaptation for solar observation occured
only recently. This paper will present preliminary results of magnetic
field observation in the HeI 1083 nm and FeI 1565 nm lines obtained
with SPIES --- a true imaging spectropolarimeter based on a large format
(64 x 32 fibers input array) fiber-optic array optimized for the study
of evolution of magnetic and thermodynamic properties of energetic and
dynamic phenomena of the sun. We will also discuss considerations for
the use of fiber-optic array for solar spectropolarimetric applications,
as well as the design of SPIES.
---------------------------------------------------------
Title: Non-Stationary Deconvolution for the IRIS NUV Slit-Jaw Imager
Authors: Jaeggli, Sarah A.; Kankelborg, Charles C.; IRIS Team
2012decs.confE..49J Altcode:
High spatial resolution context imaging is essential to linking spatial
structures with spectral signatures in the chromosphere, a critical
part of the science requirements for IRIS (Interface Region Imaging
Spectrograph). Measurements of the optical figure of the Solc filter
indicate that the NUV slit-jaw imager on IRIS will have a somewhat
broader PSF than the other instrument channels. We have developed an
advanced deconvolution technique which combines measured PSFs sampled
over the image plane to achieve the best correction for each pixel. We
have conducted an analysis of this technique on synthetic data, and
we assess the quality of the resulting images containing a variety of
simulated effects, including cosmic ray hits, photon counting noise,
discrete energetic solar events (flares), and saturation and overflow
artifacts.
---------------------------------------------------------
Title: On Molecular Hydrogen Formation and the Magnetohydrostatic
Equilibrium of Sunspots
Authors: Jaeggli, S. A.; Lin, H.; Uitenbroek, H.
2012ApJ...745..133J Altcode: 2011arXiv1110.0575J
We have investigated the problem of sunspot magnetohydrostatic
equilibrium with comprehensive IR sunspot magnetic field survey
observations of the highly sensitive Fe I lines at 15650 Å and nearby
OH lines. We have found that some sunspots show isothermal increases
in umbral magnetic field strength which cannot be explained by the
simplified sunspot model with a single-component ideal gas atmosphere
assumed in previous investigations. Large sunspots universally
display nonlinear increases in magnetic pressure over temperature,
while small sunspots and pores display linear behavior. The formation
of molecules provides a mechanism for isothermal concentration of
the umbral magnetic field, and we propose that this may explain the
observed rapid increase in umbral magnetic field strength relative to
temperature. Existing multi-component sunspot atmospheric models predict
that a significant amount of molecular hydrogen (H<SUB>2</SUB>) exists
in the sunspot umbra. The formation of H<SUB>2</SUB> can significantly
alter the thermodynamic properties of the sunspot atmosphere and
may play a significant role in sunspot evolution. In addition to the
survey observations, we have performed detailed chemical equilibrium
calculations with full consideration of radiative transfer effects
to establish OH as a proxy for H<SUB>2</SUB>, and demonstrate that a
significant population of H<SUB>2</SUB> exists in the coolest regions
of large sunspots.
---------------------------------------------------------
Title: An Observational Study of the Formation and Evolution of
Sunspots
Authors: Jaeggli, Sarah A.; Lin, H.; Uitenbroek, H.
2011SPD....42.0302J Altcode: 2011BAAS..43S.0302J
It is well known that the thermal-magnetic relation in sunspots can
be non-linear. Previous investigations ascribe the non-linearity
of the relation to changing geometrical height of the measurement
due to radiative transfer effects (Wilson Depression) and the poorly
determined magnetic field curvature force. However, the very coolest
regions of some sunspots show a rapid increase in umbral magnetic
field strength relative to temperature which cannot be explained
by the simplified sunspot model with single-component ideal gas
atmosphere which has been previously assumed. This represents a
fundamental flaw in our understanding of the sunspot equilibrium
problem. Existing multiple-component sunspot atmospheric models
predict that a large amount of molecular hydrogen (H2) exists in
the sunspot umbra. The formation of molecules provides a mechanism
for isothermal concentration of the umbral magnetic field which may
explain the observed rapid increase in umbral magnetic field strength
relative to temperature. We have characterized the equilibrium forces
in sunspots using simultaneous visible and IR sunspot magnetic field
survey observations of the highly sensitive Fe I lines at 6302 and
15650 Angstroms and nearby OH lines which have been conducted with
the new Facility Infrared Spectropolarimeter (FIRS) at the Dunn Solar
Telescope. We have performed detailed chemical equilibrium calculations
with full consideration of radiative transfer effects to establish OH
as a proxy for H2, and demonstrate that a significant population of H2
exists in the coolest regions of large and more mature sunspots. We
further point out that the formation of H2 can significantly alter
the thermodynamic properties of the sunspot atmosphere and may play
a significant role in sunspot evolution.
---------------------------------------------------------
Title: Spectropolarimetry of Chromospheric Magnetic and Velocity
Structure Above Active Regions
Authors: Schad, T. A.; Jaeggli, S. A.; Lin, H.; Penn, M. J.
2011ASPC..437..483S Altcode: 2011arXiv1101.0631S
Active regions often host large-scale gas flows in the
chromosphere presumably directed along curved magnetic field
lines. Spectropolarimetric observations of these flows are critical to
understanding the nature and evolution of their anchoring magnetic
structure. We discuss recent work with the Facility Infrared
Spectropolarimeter (FIRS) located at the Dunn Solar Telescope in New
Mexico to achieve high-resolution imaging-spectropolarimetry of the Fe
I lines at 630 nm, the Si I line at 1082.7 nm, and the He I triplet at
1083 nm. We present maps of the photospheric and chromospheric magnetic
field vector above a sunspot as well as discuss characteristics of
surrounding chromospheric flow structures.
---------------------------------------------------------
Title: Molecule Formation and Magnetic Field Evolution in Sunspots
Authors: Jaeggli, S. A.; Lin, H.; Uitenbroek, H.
2011ASPC..437..473J Altcode:
In a sunspot the magnetic field provides horizontal support to keep
the warm, high pressure photosphere from intruding into the cool,
low pressure sunspot atmosphere. In the very coolest regions of
the umbra a rapid increase in magnetic field strength relative to
temperature has been observed by many authors although its origins
have remained unknown. In these regions the magnetic and gas pressure
forces have found a different state which the current simplified theory
of magnetohydrostatic equilibrium cannot quantitatively describe. It
is well known that molecules form in sunspots. The formation of a
large molecular fraction would alter the physical characteristic of
the gas, providing a mechanism for concentrating the umbral magnetic
field. The formation of molecules may be responsible for the observed
rapid increase of the magnetic field strength observed in the coolest
regions of the sunspots and may play a significant role in sunspot
evolution. We investigate this problem with atmospheric models and
present preliminary results from observations taken with the new
Facility Infrared Spectropolarimeter on the Dunn Solar Telescope.
---------------------------------------------------------
Title: An observational study of the formation and evolution of
sunspots
Authors: Jaeggli, Sarah A.
2011PhDT........97J Altcode:
This dissertation focuses on the problem of molecules and the
horizontal balance of forces in sunspots. Sunspots are quasi-static
features on the solar surface and can be considered to be in a
state of equilibrium. The weaker gas pressure of the cool sunspot
interior is horizontally supported against the higher pressure of
the hotter quiet-Sun by a strong vertical magnetic field. However,
some sunspots show a rapid increase in magnetic pressure relative to
the temperature of the gas in the coolest regions of the sunspot,
implying that an isothermal decrease in the gas pressure must have
occurred. The current model of sunspots is unable to describe this
deviation from the assumed equilibrium state of the magnetic field
and thermal gas pressure observed in these sunspots. Another method
of altering the pressure of the gas must be occurring. The formation
of molecules in sunspots may be the key to solving this puzzle. The
sunspot interior provides a cool environment where molecules can form
in abundance. As atoms become bound into molecules the total particle
number of the gas is decreased. A sufficiently large molecular fraction
could significantly alter the properties of the sunspot plasma,
and specifically provide a mechanism for concentrating the magnetic
field by non-thermally lowering the gas pressure. I have investigated
the equilibrium condition of sunspots of different sizes and in a
variety of evolutionary phases through a Milne-Eddington inversion
of spectropolarimetric observations of the Zeeman-split Fe I lines
at 6302 and 15650 A to obtain their thermal and magnetic topology. I
carried out a calculation of the detailed radiative transfer and
chemical equilibrium of model sunspot atmospheres to determine the
molecular gas fraction. Several sunspots show unambiguous cases of
isothermal magnetic field intensification, which can only be explained
by the formation or destruction of a large molecular population. All
sunspots with magnetic fields stronger than 2500 G and temperatures
cooler than 5800 K consistently show a signature of magnetic field
over-concentration, consistent with molecular hydrogen formation of
a few percent of the total gas fraction. The formation of this large
molecular population has widespread implications for sunspot physics.
---------------------------------------------------------
Title: Magnetic Field Measurements at the Photosphere and Coronal Base
Authors: Judge, P. G.; Centeno, R.; Tritschler, A.; Uitenbroek, H.;
Jaeggli, S.; Lin, H.
2010AGUFMSH31A1783J Altcode:
We have obtained vector polarimetric measurements in lines of Fe I
(630nm), Ca II (854nm) and He I (1083nm) of several active regions
during 3-14 June 2010. The measurements were made at the Dunn Solar
Telescope at Sacramento Peak Observatory, using the FIRS and IBIS
instruments simultaneously. We discuss these and SDO data for NOAA
11076. The seeing was very good or excellent and the adaptive
optics system functioned well. In this preliminary analysis we
compare extrapolations of photospheric fields with the constraints
available from Stokes polarimetry, including the morphology and
kinematic properties of fibrils. Connections to the corona will also be
discussed. The implications for field extrapolations from photospheric
measurements will be discussed. We will make the reduced data freely
available on the web for interested researchers.
---------------------------------------------------------
Title: Utilization of redundant polarized solar spectra to infer
the polarization properties of the new generation of large aperture
solar telescopes
Authors: Elmore, David F.; Lin, Haosheng; Socas Navarro, Héctor;
Jaeggli, Sarah A.
2010SPIE.7735E..4EE Altcode: 2010SPIE.7735E.147E
Spectro-polarimetry plays an important role in the study of solar
magnetism and strongly influences the design of the new generation of
solar telescopes. Calibration of the polarization properties of the
telescope is a critical requirement needed to use these observations to
infer solar magnetic fields. However, the large apertures of these new
telescopes make direct calibration with polarization calibration optics
placed before all the telescope optical elements impractical. It is
therefore desirable to be able to infer the polarization properties
of the telescope optical elements utilizing solar observations
themselves. Taking advantage of the fact that the un-polarized,
linearly, and circularly polarized spectra originating from the Sun are
uncorrelated, we have developed techniques to utilize observations
of solar spectra with redundant combination of the polarization
states measured at several different telescope configurations to
infer the polarization properties of the telescope as a whole and of
its optical elements. We show results of these techniques applied to
spectro-plarimetric data obtained at the Dunn Solar Telescope.
---------------------------------------------------------
Title: Magnetic field measurements at the photosphere and coronal base
Authors: Judge, Philip; Centeno, R.; Tritschler, A.; Uitenbroek, H.;
Jaeggli, S.; Lin, H.
2010shin.confE..56J Altcode:
We have obtained vector polarimetric measurements in lines of Fe I
(630nm), Ca II (854nm) and He I (1083) of several active regions during
3-14 June 2010. The measurements were made at the Dunn Solar Telescope
at Sacramento Peak Observatory, using the FIRS and IBIS instruments
simultaneously. We discuss data for NOAA 11076 observed on 4 June
2010. The seeing was very good or excellent and the adaptive optics
system functioned well. In this preliminary analysis we compare linear
extrapolations of photospheric fields with the constraints available
from Stokes polarimetry, including the morphology and kinematic
properties of fibrils. The implications for field extrapolations from
photospheric measurements will be discussed. We will make the reduced
data freely available on the web for interested researchers.
---------------------------------------------------------
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 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: Erratum: “Localized Enhancements of Fe<SUP>+10</SUP> Density
in the Corona as Observed in Fe XI 789.2 nm during the 2006 March
29 Total Solar Eclipse” (<A href="/abs/2007ApJ...663..598H">ApJ,
663, 598 [2007]</A>)
Authors: Habbal, Shadia Rifai; Morgan, Huw; Johnson, Judd; Arndt,
Martina Belz; Daw, Adrian; Jaeggli, Sarah; Kuhn, Jeff; Mickey, Don
2007ApJ...670.1521H Altcode:
The eclipse image of Figure 3 was provided to the authors by
Jackob Strikis of the Elizabeth Observatory, Athens, who claimed
authorship. However, shortly after publication the authors discovered
that this eclipse image was in fact a preliminary version of an
image belonging to Prof. Miloslav Druckmüller, taken during the
2006 total solar eclipse from Libya at 30°56.946' N, 24°14.301'
E, and at an altitude of 158 m. This image can be found at <A
href="/abs/2007ApJ...663..598H">ApJ, 663, 598 [2007]</A>. We extend our
gratitude to Prof. Druckmüller, from Brno University of Technology,
Czech Republic, who brought this incident to our attention, and who
has graciously accepted our apology for this unintentional mishap. A
forthcoming article in collaboration with Prof. Druckmüller is in
preparation.
---------------------------------------------------------
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: Localized Enhancements of Fe<SUP>+10</SUP> Density in the
Corona as Observed in Fe XI 789.2 nm during the 2006 March 29 Total
Solar Eclipse
Authors: Habbal, Shadia Rifai; Morgan, Huw; Johnson, Judd; Arndt,
Martina Belz; Daw, Adrian; Jaeggli, Sarah; Kuhn, Jeff; Mickey, Don
2007ApJ...663..598H Altcode:
The first ever image of the full solar corona in the Fe XI 789.2 nm
spectral line was acquired during the total solar eclipse of 2006
March 29. Several striking features stand out in the processed image:
(1) The emission extended out to at least 3 R<SUB>solar</SUB> in
streamers. (2) A bubble-like structure, occupying a cone of about 45°
and reaching out to 1 R<SUB>solar</SUB> above the limb, was observed
southward of a bright active region complex close to the limb. (3)
Localized intensity enhancements were found in different parts of
the corona at heights ranging from 1.2 to 1.5 R<SUB>solar</SUB>. (4)
Striations extended out to the edge of the field of view above an almost
north-south-oriented prominence. Comparison with the corresponding
white-light image taken simultaneously during the eclipse showed
no evidence for these localized enhancements, and the bubble-like
structure and striations, while present, did not stand out in the same
manner. The extent of the Fe XI emission is attributed to the dominance
of radiative over collisional excitation in the formation of that
spectral line. The localized intensity enhancements, observed only in
Fe XI and not in white light, are a signature of localized increases
in Fe<SUP>+10</SUP> density relative to electron density. These are
the first observations to show direct evidence of localized heavy
ion density enhancements in the extended corona. They point to the
importance of implementing observations of the Fe XI 789.2 nm line with
existing or future coronagraphs for the exploration of the physical
processes controlling the behavior of heavy ions in different source
regions of the solar wind.
---------------------------------------------------------
Title: The Starburst-AGN Connection: Integral Field Spectroscopy of
Merging and Seyfert 2 Galaxies
Authors: Jaeggli, Sarah A.; Joseph, R. D.
2007AAS...210.1207J Altcode: 2007BAAS...39..109J
Luminous galaxies can be powered by two different mechanisms, accretion
of matter onto a super-massive black hole at the nucleus, and a rapid
burst of star formation that produces many luminous young stars, a
"starburst." Both events occur inside a large optical depth of dust:
a Seyfert 2 through its dusty torus and starbursts through their dusty
cocoons. Using the UIST integral field unit on the United Kingdom
Infrared Telescope we make observations in the K-band where obscuration
due to dust is ten times less than at visible wavelengths. With
a resolution of 900 and a field of 6 x 3.3 square arcseconds, the
integral field unit allows us to use infrared spectral diagnostics
for a sample of galaxies identified as merging starbursts and another
sample identified as Seyfert 2s to investigate the presence of both
starbursts and AGNs in both samples, and look for evidence of the
starburst-AGN connection.
---------------------------------------------------------
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: 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: Penumbral Moving Magnetic Features
Authors: Penn, M. J.; Jaeggli, S. A.; Henney, C. J.; Luszcz, S.;
Walton, S. R.
2006ASPC..358...31P Altcode:
Moving magnetic features are observed in the penumbrae of two sunspots
with time sequences of vector magnetic field measurements taken in
the infrared Fe I 1565 nm spectral line (g=3). These features move
with similar radial velocities as previously observed continuum and
G-band features, and confirm a short sequence of penumbral magnetic
observations in the visible. These features move with similar speeds
to the moving magnetic features seen outside sunspot penumbrae, and
in some cases they are seen to cross the penumbral boundary and move
across the sunspot moat. Magnetic and flow parameters are briefly
compared with predictions from the moving flux tube model.
---------------------------------------------------------
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: 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: Searching for Moving Magnetic Features at 1565 nm
Authors: Jaeggli, S. A.; Penn, M. J.; Henney, C. J.
2005AGUSMSP41B..01J Altcode:
Spectropolarimetric data of the active region 10663 was taken with
the CSUN-NSO IR camera and the McMath-Pierce telescope on August 26,
2004 from 16:35 to 21:02 UT. Utilizing the Zeeman split Fe I line near
1565 nm, the data is processed to remove instrumental polarization
and a Milne-Eddington inversion technique is applied. The results of
the inversion are used to examine the physical properties and radial
motions of moving magnetic features which appear to originate in the
sunspot penumbra.
---------------------------------------------------------
Title: Moving Magnetic Features Inside the Penumbra of NOAO 10008
Authors: Luszcz, S. H.; Penn, M. J.; Jaeggli, S. A.; Henney, C. J.
2005AGUSMSP11A..05L Altcode:
Over 30 years of observations and theories comprise the study of moving
magnetic features (MMFs). MMFs, which often occur in opposite polarity
pairs, migrate radially outward through the sunspot moat at speeds of
about 1 km~s-1. A sequence of sixteen scans of the active region NOAO
10008 were taken using the NSO-CSUN IR camera at the NSO McMath-Pierce
Solar Telescope on 24 June 2002 17:38-21:59. Using the Fe I absorption
line at 1564.8nm, magnetogram images and maps of the magnetic field
vector were produced, revealing magnetic features within the penumbra
that appear to move radially outward at similar velocities and azimuth
angles as those of MMFs in the moat. We use polar time slice images
to measure the radial velocities of both types of features. This
work is carried out through the National Solar Observatory Research
Experiences for Undergraduate (REU) site program, which is co-funded
by the Department of Defense in partnership with the National Science
Foundation REU Program.
---------------------------------------------------------
Title: The 1564.6nm CN Line in Sunspots
Authors: Penn, M. J.; Jaeggli, S. A.
2005AGUSMSP11A..02P Altcode:
The line strength of CN absorption has been observed to vary with
the continuum intensity within sunspots, and the Doppler shift of
the CN line at 1564.6nm has been shown to reveal fast Evershed flows
in the penumbra. We examine several sunspots observed from 2002-2005
using intensity spectroscopy and spectropolarimetry to determine the
line strength, plasma flow velocity, and the local magnetic field
configuration as functions of position in these sunspots.
---------------------------------------------------------
Title: IR Vector Magnetic Fields I: Instrumental Polarization
Correction
Authors: Jaeggli, S. A.; Penn, M. J.
2004AAS...204.3706J Altcode: 2004BAAS...36R.709J
Instrumental polarization is evident in the spectra of active
region 10008 taken with the CSUN-NSO IR camera at the McMath-Pierce
telescope on June 24, 2002. Several iron lines near 15650 Å in the
spectra exhibit Zeeman splitting. Using a technique described by Kuhn
et. al. (1994) the original polarization is restored. For all Zeeman
split lines in the spectra the corrected Stokes profiles for the Q and
U components show symmetry, while Stokes V is made antisymmetric with
no central component. <P />The observed Stokes vector is related to the
true Stokes vector through the formula S<SUB>true</SUB> = M<SUP>-1</SUP>
S<SUB>obs</SUB> where M<SUP>-1</SUP> is the inverse Mueller matrix. The
correction coefficients from the Kuhn method are used to compute the
inverse Mueller matrix for light path of the entire system. The expected
inverse Mueller matrix is computed for the telescope at each scan time
using a simple model described by Bernasconi (1997) but assuming the
n and k values of the index of refraction are the same for each mirror
surface. A least squares technique is used to fit this telescope model
to the measured inverse Mueller matrix for the system. The telescope
model can account for most of the measured cross-talk except for the
observed Stokes Q to Stokes V cross-talk which is thought to occur in
the polarimeter.
---------------------------------------------------------
Title: IR Vector Magnetic Fields II: Atomic and Molecular Line
Polarization in a Sunspot
Authors: Penn, M. J.; Jaeggli, S. A.; Henney, C. J.; Walton, S. R.;
Ceja, J. A.
2004AAS...204.3705P Altcode: 2004BAAS...36..709P
Full Stokes I,Q,U and V measurements of the active region NOAA 10008
were taken from 21-27 June 2002 at the NSO Kitt Peak McMath/Pierce
solar telescope using the CSUN/NSO HgCdTe IR camera and polarimeter at
1565nm. The data is corrected for instrumental polarization as discussed
in Paper I. Here the initial analysis of the atomic and molecular
line polarization data is presented. <P />Inversion of the Fe I g=3
1564.8nm line data with a modified Skumanich and Lites Milne-Eddington
technique is used to measure photospheric magnetic field parameters. A
sequence of scans covering several hours of time shows evolution of
the magnetic field. Examination of the linear polarization of the OH
1565.2nm shows curious temporal variation which results in a magnetic
azimuth radically different from that measured using the photospheric
lines. (Similar OH polarization behavior is seen in data from the
CSUN San Fernando Observatory vacuum telescope taken with the CSUN/NSO
camera in active region NOAA 10069 on 12 Aug 2002.) Finally, maps of
the CN 1564.6nm Stokes I line shift show rapid penumbral Evershed
flows and a curious signal in the sunspot umbra. <P />Some of this
work is carried out through the National Solar Observatory Research
Experiences for Undergraduate (REU) site program, which is co-funded
by the Department of Defense in partnership with the National Science
Foundation REU Program.
---------------------------------------------------------
Title: An Online Astronomy Course VS. A Interactive Classroom
Authors: Slater, Timothy F.; Bailey, Janelle M.; Jaeggli, Sarah A.;
Jones, Lauren V.; Lee, Ariane C.
2003IAUSS...4E..27S Altcode:
Contemporary science education reforms emphasize building instruction
around students’ pre-instructional beliefs fostering a learning
environment where students interact with information and phenomena
and providing students with frequent feedback to help them monitor
their own learning. Recently personal computers and the Internet have
given students access to scientific data sets and visualization tools
that only professional scientists could use a few years before. With
these things in mind we designed a hypermedia learning experience
for introductory astronomy (Astronomy Online) that matches Internet
technology with how people learn. Astronomy Online was used as the sole
delivery system for courses offered during the Fall 2002 semester. The
courses are run online. In one manifestation the course was delivered to
middle and secondary school teachers spread across the globe. In another
version the course was delivered to college undergraduate non-science
majors where the only class meetings were a single orientation session
and three on-campus exams. We compare these with on-campus courses
that use highly interactive teaching techniques by studying common
examination questions the Astronomy Diagnostic Test an attitude survey
and interviews with students
---------------------------------------------------------
Title: An Online Interactive Astronomy Course for Non-Science Majors
Authors: Slater, T. F.; Jones, L. V.; Bailey, J. M.; Jaeggli, S. A.;
Lee, A. C.
2002AAS...201.8803S Altcode: 2002BAAS...34.1249S
Contemporary science education reforms emphasize the need to build
instruction around students' pre-instructional beliefs, to foster
a productive learning environment for students to interact with
information and phenomena, and to provide students with frequent
feedback to help them monitor their own learning. Over the last five
years, personal computers and the Internet have given students the
opportunity to explore actual scientific data sets and use scientific
visualization tools in ways that only professional scientists could
only a few years before. Taken together, the authors have created
a hypermedia learning experience for introductory astronomy that
matches Internet technology with how people learn. This course weaves
multimedia visualizations into a structured learning environment
by dividing complex concepts into bite-size pieces. Each cognitive
piece contains hyperlinks explaining all terms as well as illustrated
using high-resolution images, animations, and videos which students
manipulate to answer questions. Each module helps students engage in
the pursuit of astronomy by providing activities where students make
astronomical observations. Learners are required to answer pre-module
questions, not as multiple-choice questions, but as written narratives,
about the concept under study to make their knowledge explicit. At the
conclusion, students compare new ideas with their initial answers and
evaluate various alternative explanations. Astronomy Online was used
as the sole delivery system for a course offered during the Fall 2002
semester. The course was run online; the only class meetings were a
single orientation session and three on-campus exams. We compare this
with on-campus courses that use highly interactive teaching techniques
by studying common examination questions, the Astronomy Diagnostic Test,
an attitude survey, and interviews with students.