Abstract details

Several theoretical and empirical libraries became available in the last years for population synthesis. We are comparing them to assess their quality and the impact of their incompletness and limitations on the population models. We are in particular presenting ELODIE.4, a library of 4000 spectra released at a reciprocal resolution of R=10000. Thanks to the good resolution, precise and self-consistent determinations of the atmospheric parameters are possible in most of their range (precision of e_Teff = 5%, e_Fe/H =0.05, e_logg = 0.1). We discuss the caveats of the interpolation of a library to generate a grid for population synthesis and the various problems linked to flux calibration, correction of Galactic extinction and stellar rotation and binarity. Finally, we introduce our attempts to produce an empirical grid over a large spectra range (300-800 nm; R=10000) and give a first taste of the ELODIE.5 library based on 8000 spectra with a resolution in alpha/Fe.