Research Activity

My research activity is organized around the relationship between star formation and activity in the nuclei of galaxies. This involves the use of quite a few observational techniques, both photometric and spectroscopic, in various spectral ranges, from the far ultraviolet to the near infrared. Also, for the study of these data, I am proficient in the use of several techniques of spectroscopic analysis, such as the computation of the physical conditions (temperature, density, etc.), and chemical abundances, dating the age of stellar populations, use of complex numerical codes of photoionization (CLOUDY), stellar population synthesis (SED@Starburst99), stellar atmospheres (TLUSTY), etc. The main research topics on which I am involved include the following:

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 (Teff >= 27500 K) and LTE line-blanketed models (Phoenix) for cool (3000 K <= Teff <= 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.