A Library of Semi-Empirical Stellar Spectra With Varying Abundance Element Ratios

Abstract

We have computed a new theoretical library of stellar spectra, from Near-UV to Near-IR, with varying abundance ratios of α elements. The current project is aimed at building a new set of semi-empirical stellar spectral libraries that incorporate both the non-solar abundance pattern predictions of theoretical stellar spectra and the accuracy of empirical stellar spectra. The adapted theoretical library is used to derive abundance-dependent spectral responses. These differential spectral responses are applied to observed stars to create semi-empirical versions of both the XSL and MILES stellar libraries, with varying abundances values of α -elements. The new semi-empirical XSL and MILES libraries will incorporate reliable differential corrections for cool stars, which are particularly relevant in the NIR range of integrated galaxy spectra. The XSL is particularly advantageous as it has moderately high resolving power of R 10000 with a wide spectral range coverage from the U to K band (i.e. from 0.3 to 2.3 μm) but also with an unprecedented coverage of atmospheric parameters. Such properties make it an ideal library to compute stellar population models to interpret a wide variety of galaxy spectra.