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Stellar population models in the UV, I : characterisation of the New Generation Stellar Library

Mina Koleva (UGent) and A Vazdekis
Author
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Abstract
Context. 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. Aims. 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. Methods. For our analyses we used ULySS, a full spectrum fitting package, fitting the NGSL spectra against the MILES interpolator. Results. We find that the wavelength calibration is precise up to 0.1 px, after correcting a systematic effect in the optical range. The spectral resolution varies from 3 angstrom in the UV to 10 angstrom in the near-infrared (NIR), corresponding to a roughly constant reciprocal resolution R = lambda/delta lambda approximate to 1000 and an instrumental velocity dispersion sigma(sins) approximate to 130 km s(-1). We derived the atmospheric parameters homogeneously. The precision for the FGK stars is 42 K, 0.24 and 0.09 dex for T-eff, logg and [Fe/H], respectively. The corresponding mean errors are 29K, 0.50 and 0.48 dex for the M stars, and for the OBA stars they are 4.5 percent, 0.44 and 0.18 dex. The comparison with the literature shows that our results are not biased.
Keywords
methods: data analysis, stars: fundamental parameters, HORIZONTAL-BRANCH STARS, BLUE STRAGGLER STARS, ATMOSPHERIC PARAMETERS, INTERSTELLAR EXTINCTION, FUNDAMENTAL PARAMETERS, INTEGRATED SPECTRA, SPECTROSCOPIC AGES, GLOBULAR-CLUSTERS, SYNTHETIC SPECTRA, RESOLUTION

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Citation

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MLA
Koleva, Mina, and A Vazdekis. “Stellar Population Models in the UV, I : Characterisation of the New Generation Stellar Library.” ASTRONOMY & ASTROPHYSICS 538 (2012): n. pag. Print.
APA
Koleva, Mina, & Vazdekis, A. (2012). Stellar population models in the UV, I : characterisation of the New Generation Stellar Library. ASTRONOMY & ASTROPHYSICS, 538.
Chicago author-date
Koleva, Mina, and A Vazdekis. 2012. “Stellar Population Models in the UV, I : Characterisation of the New Generation Stellar Library.” Astronomy & Astrophysics 538.
Chicago author-date (all authors)
Koleva, Mina, and A Vazdekis. 2012. “Stellar Population Models in the UV, I : Characterisation of the New Generation Stellar Library.” Astronomy & Astrophysics 538.
Vancouver
1.
Koleva M, Vazdekis A. Stellar population models in the UV, I : characterisation of the New Generation Stellar Library. ASTRONOMY & ASTROPHYSICS. 2012;538.
IEEE
[1]
M. Koleva and A. Vazdekis, “Stellar population models in the UV, I : characterisation of the New Generation Stellar Library,” ASTRONOMY & ASTROPHYSICS, vol. 538, 2012.
@article{4130758,
  abstract     = {Context. 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. 
Aims. 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. 
Methods. For our analyses we used ULySS, a full spectrum fitting package, fitting the NGSL spectra against the MILES interpolator. 
Results. We find that the wavelength calibration is precise up to 0.1 px, after correcting a systematic effect in the optical range. The spectral resolution varies from 3 angstrom in the UV to 10 angstrom in the near-infrared (NIR), corresponding to a roughly constant reciprocal resolution R = lambda/delta lambda approximate to 1000 and an instrumental velocity dispersion sigma(sins) approximate to 130 km s(-1). We derived the atmospheric parameters homogeneously. The precision for the FGK stars is 42 K, 0.24 and 0.09 dex for T-eff, logg and [Fe/H], respectively. The corresponding mean errors are 29K, 0.50 and 0.48 dex for the M stars, and for the OBA stars they are 4.5 percent, 0.44 and 0.18 dex. The comparison with the literature shows that our results are not biased.},
  articleno    = {A143},
  author       = {Koleva, Mina and Vazdekis, A},
  issn         = {0004-6361},
  journal      = {ASTRONOMY & ASTROPHYSICS},
  keywords     = {methods: data analysis,stars: fundamental parameters,HORIZONTAL-BRANCH STARS,BLUE STRAGGLER STARS,ATMOSPHERIC PARAMETERS,INTERSTELLAR EXTINCTION,FUNDAMENTAL PARAMETERS,INTEGRATED SPECTRA,SPECTROSCOPIC AGES,GLOBULAR-CLUSTERS,SYNTHETIC SPECTRA,RESOLUTION},
  language     = {eng},
  pages        = {13},
  title        = {Stellar population models in the UV, I : characterisation of the New Generation Stellar Library},
  url          = {http://dx.doi.org/10.1051/0004-6361/201118065},
  volume       = {538},
  year         = {2012},
}

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