corrected typo -- 2nd version Assigned ID: 699 ----- Attempting Submission 1 (Fri Mar 07 22:59:23 GMT 2008) ----- Phase I Proposal 699 (m33sizes.apt) successfully submitted. ----- Attempting Submission 2 (Fri Mar 07 23:04:43 GMT 2008) ----- We propose to study the mass-radius relationship of star clusters in M33, from the vast amount of archival HST data that has accumulated on this nearby galaxy. These data, taken for a large variety of programs, can be assembled to provide a comprehensive, high resolution view of (nearly) the entire disk of M33, which will allow us to study the detailed properties of at least ~500 clusters, and possibly many more. The clusters span ages from a few millions of years to more than 10 billion years, and are close enough that with HST we can measure a full suite of structural parameters, including half-light, core, and tidal radii, cluster density and more. Our immediate goal is to determine the initial mass-radius relation of these star clusters, and how this changes over time. Determining these relations for a relatively complete sample of star clusters in a single galaxy will enable us to address many questions on the dynamical state and evolution of star clusters in general. We aim in particular to study the evolution of the cluster mass function over time, in order to establish whether or not the mass function depends on cluster density, as has been recently shown for old globular cluster systems in the Milky Way and Sombrero galaxies. We will thus determine directly whether the mass-radius relation and the mass function of the M33 cluster system evolve together, as expected if evaporation due to internal, two-body relaxation is the dominant process responsible for evolving the cluster mass function. Due to its proximity, rich cluster system, and available datasets, M33 is possibly the best galaxy to accomplish these goals.

UNRESOLVED STELLAR POPULATIONS AND GALAXY STRUCTURE 12 65264 false 0.0 0.0 false false false false false SUPPORTED