Resolved Stellar Populations & Globular Clusters

Galaxies are made of stars, gas and the illusive dark matter. In those galaxies that are close enough to us we can resolve the individual stars. Through photometric observations colors and magnitudes of individual stars are determined. The distribution of the stars within the color-magnitude diagram is the end product of the star formation history of the galaxy. The spectroscopy allows the determination of the chemical composition of stars and in particular the abundances of different elements.

Star clusters are the simplest form of the stellar population. They are ensambles of stars that have formed together at the same time and thus they all have the same chemical composition. However, recent studies have shown that this simple picture is not quite so simple. Many Milky Way globular clusters have been found to contain multiple stellar populations with subtle differences in light element abundances, and some massive clusters show spread in s-process and few most massive ones also star-to-star variations in iron-peak element abundances. Old globular clusters are easily observed at great distances and can be used as probes of the early stages of star formation history in galaxies where individual stars cannot be resolved.

My research interests are centered on the studies of resolved stellar populations and (old) star clusters in nearby galaxies. On the right there are links to the pages that summarize the two main projects I am involved in: the Cen A/NGC 5128 project, and the Milky Way bulge project. I have supervised or co-supervised several Master and PhD thesis students, mainly through the ESO studentship and IMPRS PhD programmes. My own PhD thesis, which I defended in 2002 at the Pontificia Universidad Catolica in Chile, was a study of stellar populations in Centaurus A/NGC 5128 giant elliptical and WLM dwarf irregular galaxy. Before that, I made a detailed study of a symbiotic variable star YY Her, as part of my undergraduate thesis work at the Asiago Observatory. During my stay in Asiago Observatory between 1996-1998, I observed many other variable stars, in particular cataclysmic variables, symbiotic stars and some Supernovae, using the Asiago 1.8m and 1.2m telescopes. The Publications link contains a list of my most recent papers, as well as links to all my refereed and non-refereed publications through ADS.