An extension of the MILES library with derived Teff, log  g, [Fe/H], and [α/Fe]

Abstract

Extragalactic astronomy and stellar astrophysics are intrinsically related. In fact, the determination of important galaxy properties such as stellar masses, star formation histories or chemical abundances relies on the ability to model their stellar populations. One important ingredient of these models are stellar libraries. Empirical libraries must have a good coverage of Teff, [Z/H], and surface gravity, and have these parameters reliably determined. MILES is one of the most widely used empirical libraries. Here we present an extension of this library with 205 new stars especially selected to cover important regions of the parameter space, including metal poor stars down to [Fe/H] ∼ −1.0. We describe the observations and data reductions as well as a new determination of the stellar parameters, including [α/Fe] ratio. The new MILES library contains 1070 stars with homogeneous and reliable determination of [Fe/H], Teff, log g and [α/Fe] ratio.