Stellar Population Synthesis models

• Evolutionary Stellar Population Synthesis at High Spectral Resolution: Optical Wavelengths.
  

We present the single stellar population (SSP) synthesis results of our new synthetic stellar atmosphere models library with a spectral sampling of 0.3 Å, covering the wavelength range from 3000 Å to 7000Å for a wide range of metallicities (twice solar, solar, half and 1/10 solar).  The stellar library is composed of 1650 spectra computed with the latest improvements in stellar atmospheres. In particular it incorporates non-LTE line-blanketed models for hot (T_eff >= 27500 K) and LTE line-blanketed models (Phoenix) for cool (3000 K <= T_eff <= 4500 K) stars. Because of the high spectral resolution of this library, evolutionary synthesis models can be used to predict the strength of numerous weak absorption lines, and the evolution of the profiles of the strongest lines over a wide range of ages. The SSP results have been calculated for ages 1 Myr to 17 Gyr using the stellar evolutionary provided by the Geneva and Padova-tracks groups. For young stellar populations, our results have a very detailed coverage of high-temperature stars with similar results for Padova and Geneva isochrones. For intermediate and old stellar populations, our results, once degraded to a lower resolution, are similar to the ones obtained by other groups apart from limitations imposed by the stellar evolutionary physics. The limitations and advantages of our library for the analysis of integrated populations are described. The full set of the stellar library and the evolutionary models are available here for retrieval or on request from authors.

• Building of stellar absorption line profile libraries in the far UV and the optical.

Stellar libraries are one of the basic ingredients of evolutionary population synthesis models. I have built a stellar library at the far-Ultraviolet, using observations of massive stars (O and B) taken by the satellites Copernicus and HUT (Hopkins Ultraviolet Telesope) that trace the profile of the Lyb and the resonance line of OVI 1032 in stellar winds. I have also built a stellar library at optical wavelengths (3700–5000 Å) using stellar atmosphere models (TLUSTY) that trace mainly the profile of H Balmer and HeI photospheric lines.


• Stellar population synthesis models: Balmer absorption lines.

The evolutionary synthesis is a powerful technique that allows to interpret the integrated light from a galaxy. It predicts the synthetic spectrum of a stellar population as a function of age, SFR, and IMF. The basic ingredients are the evolutionary stellar tracks and the stellar libraries. I have built models to predict the far-ultraviolet spectrum and the H Balmer and HeI absorption lines in star forming galaxies in the starburst and post-starburst phase.