0 Assigned ID: 1474 ----- Attempting Submission 1 (Fri Mar 01 13:41:48 GMT 2013) ----- HST surveys have shown that nuclear star clusters are nearly ubiquitous in nearby galaxies with masses similar to or lower than the Milky Way. Like in the Milky Way they can coincide with black holes at the centers of galaxies. But, the overall "occupation fraction" of black holes within nuclear clusters is largely unconstrained. Measurements of the structure, stellar content, and mass profile of nuclear star clusters enable us to predict the rate of luminous tidal disruption events in lower mass galaxies and quantify the demographics of black holes in these galaxies for the first time. We propose to analyze an extensive archive of observations of 80 nearby galaxy nuclei (D < 10 Mpc) to determine the stellar density profiles and morphology of a large number of nuclear star clusters. These mass profiles will enable us to create the first robust predictions for the rate of luminous stellar tidal disruption events in lower mass galaxies. By combining these predictions with observed tidal disruption event rates from on-going and upcoming time-domain surveys, we will be able to constrain the occupation fractions of black holes in lower mass galaxies. The stellar mass profiles will also be used to derive total stellar masses for NSCs to test galaxy-nucleus scaling relationships. Furthermore, by analyzing the morphology and color-maps of our nuclear star clusters, we will examine how mass accretes into the nuclei over a wide range of masses and across Hubble type. UNRESOLVED STELLAR POPULATIONS AND GALAXY STRUCTURE Default Medium false false false false false SUPPORTED