J/A+A/634/A133 X-Shooter Spectral Library (XSL). DR2 (Gonneau+, 2020)
The X-Shooter Spectral Library (XSL): Data Release 2.
Gonneau A., Lyubenova M., Lancon A., Trager S.C., Peletier R.F.,
Arentsen A., Chen Y.-P., Coelho P.R.T., Dries M., Falcon-Barroso J.,
Prugniel P., Sanchez-Blazquez P., Vazdekis A., Verro K.
<Astron. Astrophys. 634, A133 (2020)>
=2020A&A...634A.133G 2020A&A...634A.133G (SIMBAD/NED BibCode)
ADC_Keywords: Fundamental catalog ; Stars, standard ; Spectroscopy
Keywords: Hertzsprung-Russell and C-M diagrams - catalogs
Abstract:
We present the second data release (DR2) of the X-Shooter Spectral
Library (XSL), which contains all the spectra obtained over the six
semesters of that program. This release supersedes our first
data release from 2014, with a larger number of spectra (813
observations of 666 stars) and with a more extended wavelength
coverage as the data from the near-infrared arm of the X-Shooter
spectrograph are now included. The DR2 spectra then consist of three
segments that were observed simultaneously and, if combined, cover the
range between 300nm and 2.45um at a spectral resolving power close to
R=10000. The spectra were corrected for instrument transmission and
telluric absorption, and they were also corrected for
wavelength-dependent flux-losses in 85% of the cases. On average,
synthesized broad-band colors agree with those of the MILES library
and of the combined IRTF and Extended IRTF libraries to within 1%. The
scatter in these comparisons indicates typical errors on individual
colors in the XSL of 2-4%. The comparison with 2MASS point source
photometry shows systematics of up to 5% in some colors, which we
attribute mostly to zero-point or transmission curve errors and a
scatter that is consistent with the above uncertainty estimates. The
final spectra were corrected for radial velocity and are provided in
the rest-frame (with wavelengths in air). The spectra cover a large
range of spectral types and chemical compositions (with an emphasis on
the red giant branch), which makes this library an asset when creating
stellar population synthesis models or for the validation of
near-ultraviolet to near-infrared theoretical stellar spectra across
the Hertzsprung-Russell diagram.
Description:
The X-shooter spectra cover three wavelength ranges, referred to as
arms: ultraviolet-blue (UVB), visible (VIS) and near-infrared (NIR).
The final data products released as DR2 consist of single-arms
spectra, with linearly sampled wavelengths in the rest-frame.
Therefore, each arm has its own resolution: 9100 for the UVB, 11000
for the VIS and 7700 for the NIR. The spectra are provided as FITS
binary tables, each containing three columns: the wavelength (in nm),
the flux spectrum (in erg/s/cm2/Å), and an error spectrum (in the
same units). A set of keywords in the headers of the FITS files keep
track of various steps of the data-reduction and calibration
processes, and of results of the quality assessments. A
(non-exhaustive) list of these keywords is given in Table 8 of the
paper. The DR2 spectra are made available as two separate sets:
1. All the spectra for which a correction for slit-losses across the
spectrograph slit was possible (85% of the observations).
2. Remaining 15% of the spectra, without slit-loss correction. They
are identified via header keyword LOSS_COR, which is then set to F.
The table provided is a merged version of several tables from our
paper. It contains the list of our stars some observational properties
as described in Table C1 (coordinates, XSL_ID, MJD, arm missing or
deprecated from this data release). The comments about individual
objects from Table B1 are also included in this table.
File Summary:
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FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table.dat 401 813 Properties of our sample of XSL stars
fits/* . 2043 Individual Fits spectra corrected for slit-loss
fits_nlc/* . 345 Individual Fits spectra NOT corrected for slit-loss
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See also:
J/A+A/565/A117 : X-Shooter Spectral Library (XSL). DR1 (Chen+, 2014)
Byte-by-byte Description of file: table.dat
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Bytes Format Units Label Explanations
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1- 25 A25 --- Star Name of the star (from table C1)
26 A1 --- n_Star [?] Uncertainty flag on Star name
(see Comments)
28- 29 I2 h RAh Right ascension (J2000) (from table C1)
31- 32 I2 min RAm Right ascension (J2000) (from table C1)
34- 39 F6.3 s RAs Right ascension (J2000) (from table C1)
41 A1 --- DE- Declination sign (J2000) (from table C1)
42- 43 I2 deg DEd Declination (J2000) (from table C1)
45- 46 I2 arcmin DEm Declination (J2000) (from table C1)
48- 51 F4.1 arcsec DEs Declination (J2000) (from table C1)
54- 58 A5 --- XSLID XSL unique identifier (from table C1)
60- 69 F10.4 d MJD Modified Julian Date (from table C1)
71- 77 A7 --- ArmMissing Arm missing or deprecated (from table C1)
79-118 A40 --- FileUVB Name of UVB FITS file
(with sub-directory name)
120-159 A40 --- FileVIS Name of VIS FITS file
(with sub-directory name)
161-200 A40 --- FileNIR Name of NIR FITS file
(with sub-directory name)
202-401 A200 --- Comments Comments on individual stars (table B1)
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Acknowledgements:
Anais Gonneau, agonneau(at)ast.cam.ac.uk
(End) Patricia Vannier [CDS] 21-Jan-2020