J/A+A/673/A19 Spatially resolved solar spectra (Ellwarth+, 2023)
The IAG spectral atlas of the spatially resolved Sun:
Centre-to-limb observations.
Ellwarth M., Schafer S., Reiners A., Zechmeister M.
<Astron. Astrophys. 673, A19 (2023)>
=2023A&A...673A..19E 2023A&A...673A..19E (SIMBAD/NED BibCode)
ADC_Keywords: Sun ; Spectroscopy
Keywords: methods: observational - standards - line: profiles -
techniques: spectroscopic
Abstract:
Solar surface magneto-convection appears as granulation pattern that
impacts spectral lines in terms of both shape and wavelength. Such
induced effects also tend to vary over the observed solar disc because
of the changing observation angle and, thus, the changing observation
height as well. Centre-to-limb observations of the resolved Sun offer
an insight into the variable spectral behaviour across different
heliocentric observing positions, providing crucial information about
limb darkening, convective velocities, and line profile variability
relevant to radial velocity (RV) calculations. Thus, RV measurements
and exoplanet transit spectroscopy depend on precise reference
templates. We want to provide a spectroscopic centre-to-limb solar
atlas at high spectral resolution and high-frequency accuracy. The
atlas shall help improve the understanding of the solar atmosphere and
convection processes. We performed high-resolution observations of the
resolved quiet Sun with a Fourier transform spectrograph at the
Institut fur Astrophysik und Geophysik in Gottingen. Our dataset
contains a wavelength range from 4200Å to 8000Å. We obtained 165
spectra in total, with a spectral resolution of 0.024cm-1,
corresponding to a resolving power R of 700000 at ∼6000Å. We
present a centre-to-limb solar atlas containing 14 heliocentric
positions. To check for consistency, we investigated the FeI 6175Å
absorption line and compared our line profiles with previous
centre-to-limb observations and also with simulations. The line
profile and also the bisector profiles are generally consistent with
previous observations, but we have identified differences to model
line profiles, especially close to the solar limb.
Description:
Solar spectra for the resolved Sun. We obtained spectra for 14mu
radii for the wavelength range from 4200Å to 8000Å. Observations
were carried out between April 2020 and June 2021 on quiet Sun
regions.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
list.dat 65 14 List of fits spectra
fits/* . 14 Individual fits spectra
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Byte-by-byte Description of file: list.dat
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Bytes Format Units Label Explanations
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1- 7 I7 --- Nx Number of pixels along X-axis
9- 13 I5 Kibyte size Size of FITS file
15- 39 A25 --- FileName Name of FITS file, in subdirectory fits
41- 65 A25 --- Title Title of the FITS file
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Acknowledgements:
Momo Ellwarth, momo.ellwarth(at).uni-goettingen.de
(End) Patricia Vannier [CDS] 16-Mar-2023