scholarly journals Atomic physics and solar polarimetry

2017 ◽  
Vol 95 (9) ◽  
pp. 847-854 ◽  
Author(s):  
P.G. Judge
Keyword(s):  
Adaptive Optics ◽  
Atomic Physics ◽  
Solar Physics ◽  
Polarized Light ◽  
Initial Study ◽  
Spectral Lines ◽  
Calibration Data ◽  
Science Data ◽  
On Line ◽  
Singly Charged

Major outstanding problems in solar physics relate to solar magnetism. Spectropolarimetry offers the best, and sometimes only, method of obtaining accurate measurements of the Sun’s magnetic field. New 1.5–2 m class telescopes with adaptive optics have come on line, and the Daniel K. Inouye 4 m Solar Telescope (DKIST) will begin observing in 2019. The calibration of polarized light entering such a large and polarizing ground-based telescope represents difficult challenges. This paper explores how special polarization properties of particular atomic transitions may provide calibration data, augmenting or even avoiding time-consuming calibration observations, as well as science data. This initial study concludes that solar spectral lines exist with special polarization properties, allowing the telescope calibration to be determined. The Sun’s visible and infrared spectrum is dominated by lines of neutral atoms and singly charged ions of iron and other complex atoms. Both solar and atomic physics should jointly benefit from telescopic advances, as observers explore regimes of broader wavelength ranges, and higher spatial resolutions and polarimetric sensitivities, than they have reached in the past. Further work is in progress to identify particular transitions of practical use to aid in calibrations.

scholarly journals Project of the Large Solar Telescope with mirror 3 m in diameter

2020 ◽  
Vol 6 (2) ◽  
pp. 14-29 ◽  
Author(s):  
Victor Grigoryev ◽  
Mikhail Demidov ◽  
Dmitriy Kolobov ◽  
Vasiliy Pulyaev ◽  
Valery Skomorovsky ◽  
...  
Keyword(s):  
Adaptive Optics ◽  
Near Infrared ◽  
Solar Physics ◽  
Solar Observatory ◽  
Spectral Lines ◽  
Small Scale ◽  
Solar Telescope ◽  
Rotating Platform ◽  
Solar Telescopes ◽  
Under Construction

One of the most important problems of modern solar physics is the observation of the small-scale structure of the solar atmosphere at various heights (including the chromosphere and corona) in different spectral lines. Such observations can be made only with large solar telescopes whose main mirror has a diameter of at least 3 m. Currently, several large solar telescopes are under construction or development in the world. In 2013 in Russia, the work began on the development of a national large solar telescope with a mirror 3 m in diameter (LST-3), which is a part (subproject) of the National Heliogeophysical Complex of the Russian Academy of Sciences. The telescope is planned to be located in the Sayan Solar Observatory at an altitude of more than 2000 m. The choice was made in favor of the classic axisymmetric Gregory optical layout on an alt-azimuth mount. The scientific equipment of LST-3 will consist of several systems of narrow-band tunable filters and spectrographs for various wave ranges. The equipment will be placed both in the main coude focus on a rotating platform and in the Nasmyth focus. To achieve a diffraction resolution, high-order adaptive optics (AO) will be used. It is assumed that with a certain modification of the optical configuration, LST-3 will work as a 0.7 m mirror coronograph in near infrared lines and can also be used for observing astrophysical objects in the nighttime.

scholarly journals Diagnostic methods based on scattering polarization and the joint action of the Hanle and Zeeman effects

2008 ◽  
Vol 4 (S259) ◽  
pp. 623-632
Author(s):  
Javier Trujillo Bueno
Keyword(s):  
Magnetic Fields ◽  
Solar Physics ◽  
Energy Levels ◽  
Zeeman Effect ◽  
Polarized Light ◽  
Thomson Scattering ◽  
Stellar Atmospheres ◽  
Diagnostic Methods ◽  
Spectral Lines ◽  
Polarized Radiation

AbstractPolarized light provides the most reliable source of information at our disposal for diagnosing the physical properties of astrophysical plasmas, including the magnetic fields of the solar atmosphere. The interaction between radiation and hydrogen plus free electrons through Rayleigh and Thomson scattering gives rise to the polarization of the stellar continuous spectrum, which is very sensitive to the medium's thermal and density structure. Anisotropic radiative pumping processes induce population imbalances and quantum coherences among the sublevels of degenerate energy levels (that is, atomic level polarization), which produce polarization in spectral lines without the need of a magnetic field. The Hanle effect caused by the presence of relatively weak magnetic fields modifies the atomic polarization of the upper and lower levels of the spectral lines under consideration, allowing us to detect magnetic fields to which the Zeeman effect is blind. After discussing the physical origin of the polarized radiation in stellar atmospheres, this paper highlights some recent developments in polarized radiation diagnostic methods and a few examples of their application in solar physics.

scholarly journals Project of the Large Solar Telescope with mirror 3 m in diameter

2020 ◽  
Vol 6 (2) ◽  
pp. 19-36
Author(s):  
Victor Grigoryev ◽  
Mikhail Demidov ◽  
Dmitriy Kolobov ◽  
Vasiliy Pulyaev ◽  
Valery Skomorovsky ◽  
...  
Keyword(s):  
Adaptive Optics ◽  
Near Infrared ◽  
Solar Physics ◽  
Solar Observatory ◽  
Spectral Lines ◽  
Small Scale ◽  
Solar Telescope ◽  
Rotating Platform ◽  
Solar Telescopes ◽  
Under Construction

One of the most important problems of modern solar physics is the observation of the small-scale structure of the solar atmosphere at various heights (including the chromosphere and corona) in different spectral lines. Such observations can be made only with large solar telescopes whose main mirror has a diameter of at least 3 m. Currently, several large solar telescopes are under construction or development in the world. In 2013 in Russia, the work began on the development of a national large solar telescope with a mirror 3 m in diameter (LST-3), which is a part (subproject) of the National Heliogeophysical Complex of the Russian Academy of Sciences. The telescope is planned to be located in the Sayan Solar Observatory at an altitude of more than 2000 m. The choice was made in favor of the classic axisymmetric Gregory optical layout on an alt-azimuth mount. The scientific equipment of LST-3 will consist of several systems of narrow-band tunable filters and spectrographs for various wave ranges. The equipment will be placed both in the main coude focus on a rotating platform and in the Nasmyth focus. To achieve a diffraction resolution, high-order adaptive optics (AO) will be used. It is assumed that with a certain modification of the optical configuration, LST-3 will work as a 0.7 m mirror coronograph in near infrared lines and can also be used for observing astrophysical objects in the nighttime.

The Interpretation of Line Profiles

1977 ◽  
Vol 36 ◽  
pp. 191-215
Author(s):  
G.B. Rybicki
Keyword(s):  
Magnetic Fields ◽  
Atomic Physics ◽  
Velocity Fields ◽  
Spectral Lines ◽  
Inhomogeneous Structure ◽  
The Sun ◽  
Line Profiles ◽  
Physical Phenomena

Observations of the shapes and intensities of spectral lines provide a bounty of information about the outer layers of the sun. In order to utilize this information, however, one is faced with a seemingly monumental task. The sun’s chromosphere and corona are extremely complex, and the underlying physical phenomena are far from being understood. Velocity fields, magnetic fields, Inhomogeneous structure, hydromagnetic phenomena – these are some of the complications that must be faced. Other uncertainties involve the atomic physics upon which all of the deductions depend.

First results of an on-line adaptive optics system with atmospheric wavefront sensing by an artificial neural network

1992 ◽  
Vol 390 ◽  
pp. L41 ◽  
Author(s):  
M. Lloyd-Hart ◽  
P. Wizinowich ◽  
B. McLeod ◽  
D. Wittman ◽  
D. Colucci ◽  
...  
Keyword(s):  
Neural Network ◽  
Artificial Neural Network ◽  
Adaptive Optics ◽  
Wavefront Sensing ◽  
First Results ◽  
On Line ◽  
Artificial Neural ◽  
Adaptive Optics System

Poster Presentations

2017 ◽  
Vol 14 (S339) ◽  
pp. 281-282
Keyword(s):  
Adaptive Optics ◽  
Near Infrared ◽  
Lead Author ◽  
Light Curve Analysis ◽  
Statistical Research ◽  
Alphabetical Order ◽  
Eclipsing Binary ◽  
X Ray ◽  
Cepheid Variables ◽  
On Line

49 posters were displayed at IAU S339. The display space was adequate to allow all to be on show throughout the conference.Poster presenters were given the option of condensing the message(s) of their posters into written summaries and/or depositing a pdf of the original poster for inclusion in the on-line version of the Proceedings. Half of the poster authors responded; 12 chose to send written summaries, 9 submitted just their original pdfs, and 4 elected to send both. Workshop 1 also converted some catalogue material into an on-line poster. This Section contains the contributions that were submitted as written summaries, arranged in alphabetical order of lead author.Near-Infrared Observations of OGLE Classical and Type II Cepheid Variables in the LMC ………. 283A. Bhardwaj, L. M. Macri, S. M. Kanbur, C-C. Ngeow and H. P. SinghMultiwavelength Light-Curve Analysis of Cepheid Variables ………. 287A. Bhardwaj, S. M. Kanbur, M. Marconi, H. P. Singh, M. Rejkuba and C-C. NgeowSymbiotic Stars in the Local Group of Galaxies: POINT-AGAPE Catalogue Revisited ………. 291K. Drozd, J. Mikołajewska, M. Darnley, K. Iłkiewicz, N. Caldwell and M. SharaDetection of Sectoral Modes in the Eclipsing Binary KIC 4851217………. 295M. Fedurco, Š. Parimucha & P. GajdošKepler-410Ab and Transit Timing Variations ………. 299P. Gajdoš, Š. Parimucha and M. FedurcoSparse Spatio-Temporal Imaging of Radio Transients ………. 303J. Girard, M. Jiang, J-L. Starck and S. CorbelTesting the SALT High-Resolution Spectrograph for Pulsation Studies of roAp Stars ………. 307D. Holdsworth and D. KurtzProbing Convective Mixing in Stellar Interiors with α Centauri A and B………. 308M. Joyce and B. ChaboyerHighly Luminous SNe Associated with GRBs………. 309D. KannSearching for Pulsating Stars Using Clustering Algorithms………. 310R. Kgoadi, I. B. Whittingham and C. A. EngelbrechtPhase-resolved Spectroscopy and Photometry of the Eclipsing Polar UZ Fornacis 314Z. N. Khangale, S. B. Potter and P. A. WoudtMeteor Sky in Time-Domain Astronomy………. 318S. V. KolomiyetsFirst Results from Project SUNBIRD: Supernovæ UNmasked By Infra-Red Detection………. 322E. C. Kool, S. D. Ryder, E. Kankare, T. Reynolds, S. Mattila, M. Pérez-Torres and R. McDermidThe X-Ray Spectrum of the X-Ray Binary 4U 1728-34, observed with Suzaku ………. 323Y. Lei, H. Zhang, H. Yuan and Y. ZhangStatistical Research into Correlation between Solar Filaments and Flare Activities………. 327G. LinA CoRoT view of the ζ Aur binary HR 6902………. 329C. Maceroni, J. Montalbán, R. Da Silva, T. Semaan, B. Mosser, M. Rainer, E. Poretti and E. GriffinSearching for Long-Period Binary Central Stars of Planetary Nebulæ with SALT HRS………. 330B. Miszalski, R. Manick, J. Mikołajewska, K. Iłkiewicz, D. Kamath and H. Van WinckelCompanion(s) of the Eclipsing Binary KIC 3832716………. 331Š. Parimucha, M. Fedurco and P. GajdošEvaluating the Fraction of Obscured Supernovæ in Luminous Infrared Galaxies with Adaptive Optics Surveys………. 335T. Reynolds, S. Mattila, E. Kool, E. Kankare, S. Ryder and M. A. Pérez-TorresDetecting AGB stars in LG Dwarf Galaxies for Understanding Galaxy Formation and Evolution………. 336E. Saremi, A. Javadi, J. van Loon, H. Khosroshahi and M. TorkiAccurate Photometry with Digitized Photographic Plates of the Moscow Collection………. 340K. V. Sokolovsky D. M. Kolesnikova, N. N. Samus, S. V. Antipin and A.A. BelinskiThe All-Sky Automated Search for Supernovæ Going Global………. 344M. Stritzinger and the ASAS-SN TeamStellar Parameterisation using KPCA and SVM………. 345H. Yuan, Y. Zhang, Y., Yiqiao Dong, Z. Bai, G. Li, W. Zhang, H. Zhang and Y. ZhaoΔa Photometric Survey of the Small Magellanic Cloud………. 349M. Zejda, E. Paunzen and Z. MikulášekDesign, Build and Test of the VOEvent Network for the SVOM Chinese Ground Segment………. 353M. Zhang, M. Huang and C. Wu

scholarly journals The potential of many-line inversions of photospheric spectropolarimetric data in the visible and near UV

2019 ◽  
Vol 622 ◽  
pp. A36 ◽  
Author(s):  
T. L. Riethmüller ◽  
S. K. Solanki
Keyword(s):  
Wavelength Range ◽  
Solar Physics ◽  
Solar Observatory ◽  
Spectral Lines ◽  
Resolving Power ◽  
Short Wavelength Range ◽  
Photon Noise ◽  
Infrared Spectral ◽  
The Many

Our knowledge of the lower solar atmosphere is mainly obtained from spectropolarimetric observations, which are often carried out in the red or infrared spectral range and almost always cover only a single or a few spectral lines. Here we compare the quality of Stokes inversions of only a few spectral lines with many-line inversions. In connection with this, we have also investigated the feasibility of spectropolarimetry in the short-wavelength range, 3000 Å−4300 Å, where the line density but also the photon noise are considerably higher than in the red, so that many-line inversions could be particularly attractive in that wavelength range. This is also timely because this wavelength range will be the focus of a new spectropolarimeter in the third science flight of the balloon-borne solar observatory SUNRISE. For an ensemble of state-of-the-art magneto-hydrodynamical atmospheres we synthesize exemplarily spectral regions around 3140 Å (containing 371 identified spectral lines), around 4080 Å (328 lines), and around 6302 Å (110 lines). The spectral coverage is chosen such that at a spectral resolving power of 150 000 the spectra can be recorded by a 2K × 2K detector. The synthetic Stokes profiles are degraded with a typical photon noise and afterward inverted. The atmospheric parameters of the inversion of noisy profiles are compared with the inversion of noise-free spectra. We find that significantly more information can be obtained from many-line inversions than from a traditionally used inversion of only a few spectral lines. We further find that information on the upper photosphere can be significantly more reliably obtained at short wavelengths. In the mid and lower photosphere, the many-line approach at 4080 Å provides equally good results as the many-line approach at 6302 Å for the magnetic field strength and the line-of-sight (LOS) velocity, while the temperature determination is even more precise by a factor of three. We conclude from our results that many-line spectropolarimetry should be the preferred option in the future, and in particular at short wavelengths it offers a high potential in solar physics.

scholarly journals Numerical Simulation of Granular Convection: Effects on Photospheric Spectral Line Profiles

1980 ◽  
Vol 51 ◽  
pp. 213-224
Author(s):  
Åke Nordlund
Keyword(s):  
Spectral Line ◽  
Line Strength ◽  
Blue Shift ◽  
Spectral Lines ◽  
Line Profiles ◽  
Pressure Broadening ◽  
Solar Granulation ◽  
Velocity Fluctuations ◽  
Excitation Potential ◽  
On Line

AbstractThe results of numerical simulations of the solar granulation are used to investigate the effects on photospheric apectral lines of the correlated velocity and temperature fluctuations of the convective granular motions. It is verified that the granular velocity field is the main cause for the observed broadening and strengthening of photospheric spectral lines relative to values expected from pure thermal and pressure broadening. These effects are normally referred to as being due to “macro-turbulence” and “micro-turbulence”, respectively. It is also shown that the correlated temperature and velocity fluctuations produce a “convective blue shift” in agreement with the observed blue shift of photospheric spectral lines. Reasons are given for the characteristic shapes of spectral line bisectors, and the dependence of these shapes on line strength, excitation potential, and center to limb distance are discussed.

scholarly journals Science with Large Solar Telescopes: Overview of SpS 6

2012 ◽  
Vol 10 (H16) ◽  
pp. 439-470
Author(s):  
Gianna Cauzzi ◽  
Alexandra Tritschler ◽  
Yuanyong Deng
Keyword(s):  
Solar Physics ◽  
Stray Light ◽  
Quantum Leap ◽  
Critical Issues ◽  
On Line ◽  
Solar Telescopes ◽  
Operational Issues ◽  
Near Future ◽  
Simulations And Modeling

AbstractWith several large aperture optical and IR telescopes just coming on-line, or scheduled for the near future, solar physics is on the verge of a quantum leap in observational capabilities. An efficient use of such facilities will require new and innovative approaches to both observatory operations and data handling.This two-days long Special Session discussed the science expected with large solar telescopes, and started addressing the strategies necessary to optimize their scientific return. Cutting edge solar science as derived from state-of-the-art observations and numerical simulations and modeling was presented, and discussions were held on the role of large facilities in satisfying the demanding requirements of spatial and temporal resolution, stray-light correction, and spectro-polarimetric accuracy. Building on the experience of recently commissioned telescopes, critical issues for the development of future facilities were discussed. These included operational issues peculiar to large telecopes as well as strategies for their best use.

On Line-Affective State Monitoring Device Design

2007 ◽  
Author(s):  
Anja Lanz ◽  
Elizabeth Croft
Keyword(s):  
Affective State ◽  
Low Frequency ◽  
Human Robot Interaction ◽  
Calibration Data ◽  
Affective States ◽  
Device Design ◽  
State Monitoring ◽  
Robot Interaction ◽  
State Data ◽  
On Line

The monitoring of human affective state is a key part of developing responsive and naturally behaving human-robot interaction systems. However, evaluation and calibration of physiologically monitored affective state data is typically done using offline questionnaires and user reports. This paper investigates the potential to use an on-line device to collect user self reports that can be then used to calibrate physiologically generated affective state data. The collection of on-line calibration data is particularly germane to human-robot interaction where the physiological responses of interest include those related to more high frequency affective state events related to arousal (surprise, fear, alarm) as well as the more low frequency events (contentment, boredom, pleasure). In this context, this paper describes the development of an experimental device, and a preliminary study, to answer the question: Can people report, on-line, two degree of freedom continuous affective states using a hand held device suitable for calibration of physiologically obtained signals? In the following paper, we report on both the device design and user trials. Further work, using the device to calibrate existing models of the user’s affective state during human-robot interaction, is ongoing and will be reported at the time of the conference.

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