J/A+A/538/A143 Atmospheric parameters of stars for UV models (Koleva+, 2012)
Stellar population models in the UV.
I. Characterisation of the New Generation Stellar Library.
Koleva M., Vazdekis A.
<Astron. Astrophys. 538, A143 (2012)>
=2012A&A...538A.143K 2012A&A...538A.143K
ADC_Keywords: Stars, atmospheres ; Atlases ; Effective temperatures ;
Abundances, [Fe/H]
Keywords: methods: data analysis - stars: fundamental parameters
Abstract:
The spectral predictions of stellar population models are not as
accurate in the ultra-violet (UV) as in the optical wavelength domain.
One of the reasons is the lack of high-quality stellar libraries. The
New Generation Stellar Library (NGSL), recently released, represents a
significant step towards the improvement of this situation.
To prepare NGSL for population synthesis, we determined the
atmospheric parameters of its stars, we assessed the precision of the
wavelength calibration and characterised its intrinsic resolution. We
also measured the Galactic extinction for each of the NGSL stars.
For our analyses we used ULySS, a full spectrum fitting package,
fitting the NGSL spectra against the MILES interpolator.
We find that the wavelength calibration is precise up to 0.1pix, after
correcting a systematic effect in the optical range. The spectral
resolution varies from 3Å in the UV to 10Å in the near-infrared
(NIR), corresponding to a roughly constant reciprocal resolution
R∼1000 and an instrumental velocity dispersion 130km/s. We derived the
atmospheric parameters homogeneously. The precision for the FGK stars
is 42K, 0.24 and 0.09dex for Teff, logg and [Fe/H], respectively. The
corresponding mean errors are 29K, 0.50 and 0.48dex for the M stars,
and for the OBA stars they are 4.5 percent, 0.44 and 0.18dex. The
comparison with the literature shows that our results are not biased.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
param.dat 85 378 Physical parameters adopted by this work
refs.dat 68 17 References
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See also:
III/218 : ELODIE archive (Prugniel+, 2001)
http://archive.stsci.edu/prepds/stisngsl : NGSL library home page
http://ulyss.univ-lyon1.fr : ULySS software package home page
http://www.obs.u-bordeaux1.fr/m2a/soubiran/elodie_library.html :
ELODIE home page
Byte-by-byte Description of file: param.dat
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Bytes Format Units Label Explanations
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1- 10 A10 --- Name Designation of the star
12 A1 --- SB [y] Spectroscopic binary in SIMBAD? y=yes
14- 18 I5 K Teff Effective temperature
20- 23 I4 K e_Teff ?=9999 Error on Teff
25- 28 F4.2 [cm/s2] log(g) ?=9.99 Log of the surface gravity
30- 33 F4.2 [cm/s2] e_log(g) ?=9.99 Error on log(g)
35- 39 F5.2 [Sun] [Fe/H] ?=9.99 Metallicity
41- 44 F4.2 [Sun] e_[Fe/H] ?=9.99 Error on [Fe/H]
46- 49 I4 km/s cz ?=999 Residual velocity shift (1)
51- 53 I3 km/s sig ?=999 Instrumental+physical broadening (2)
55- 58 I4 --- S/Nu Signal-to-noise ratio at 2800Å (UV)
60- 62 I3 --- S/Nb Signal-to-noise ratio at 4000Å (blue)
64- 66 I3 --- S/Ni Signal-to-noise ratio at 8000Å (I-band)
68- 72 F5.2 --- AV Extincion in V band
74- 85 A12 --- Ref References, in refs.dat file
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Note (1): cz is the mean residual velocity shift resulting from the fit to
the MILES interpolator. The shift may not be uniform throughout the
spectrum, because of uncertainties in the wavelength calibration of MILES
Note (2): sig is the Gaussian width of the mean LSF at 3500-7500Å. It
includes the (variable) instrumental broadening and the physical
broadening (rotation).
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Byte-by-byte Description of file: refs.dat
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Bytes Format Units Label Explanations
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1- 2 I2 --- Ref Reference number
4- 22 A19 --- BibCode BibCode
24- 47 A24 --- Aut Author's name
50- 68 A19 --- Com Comments
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Acknowledgements:
Mina Kolev, mina.koleva(at)gmail.com
(End) Mina Koleva [Gent Univ., Belgium], Patricia Vannier [CDS] 17-Nov-2011