Dr. Maren Hempel
University of Florida

University of Florida Astronomy Colloquium - Oct. 18th, 2006

Early-type galaxies and their sometimes not so old globular clusters

The formation and evolution of early-type galaxies is still under debate, the wealth of available data drawing a more and more diverse picture. In order to assign the underlying formation scenario to a given galaxy we need to know the age structure of the stellar content. To do so we have developed a semi-numerical method to probe the age structure in globular cluster systems, based on combined optical and near-infrared photometry. The goal is to detect possible age populations, to set some constraints on their relative age and size, and if possible, find correlations between the age structure and various galaxy parameters, e.g. environment, mass and color. Here I present the results for early-type galaxies found in clusters/groups as well as for rather isolated galaxies, which so far revealed the coexistence of globular cluster age-subpopulations in three early-type galaxies. In this talk I will describe our method of detecting age populations, based on the determination of the cumulative age distribution in the observed and in simulated globular cluster systems, its application to individual globular cluster systems and the comparison of various galaxies.