Institute for Advanced Study Informal Astrophysics Seminar

This talk presents a general picture of star cluster populations, from their formation in the clumpy ISM to their eventual dissolution in the smooth stellar field. The picture is general or unified in the sense that it encompasses most traditional categories of star clusters: associations, open clusters, populous clusters, globular clusters, etc. The key element of this picture is the mass function of clusters (spectrum of cluster masses) and its time (age) dependence, or equivalently, the joint distribution of masses and ages. HST observations have revealed some remarkable similarities in the mass-age distribution of clusters in different galaxies, analogous to similarities in the stellar mass function (IMF). This talk presents physical explanations for these observations.