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Symposium 241

Abstract details

New response functions for absorption-line indices from high-resolution spectra
Rosaria Tantalo

Basing on the huge library of 1A resolution spectra calculated by Munari et al. over a large range of Teff, logG, [Fe/H] and both for solar and enhanced abundance ratios [a/Fe], I present theoretical absorption-line indices on the Lick system. First I derive the so-called response functions (RFs) for a wide range of Teff, logG, [Fe/H] and both solar and enhanced ratios. The RFs are commonly used to correct indices with solar [a/Fe] ratios to indices with [a/Fe]>0. Not only the RFs vary with the type of star but also with the metallicity. Secondly, with the aid of this and the fitting functions (FFs) of Worthey et al., I derive the indices for single stellar populations and compare them with those obtained by previous authors, e.g. Tantalo & Chiosi. The new indices for single stellar populations are used to derive with aid of the recursive Minimum Distance method the age, metallicity and degree of enhancement of a sample of Galactic Globular Clusters for which these key parameters have been independently derived from the Colour-Magnitude Diagram and/or spectroscopic studies. The agreement is remarkably good.

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