Assigned ID: 177 ----- Attempting Submission 1 (Thu Feb 25 20:41:01 GMT 2010) ----- We propose to use the database of the Millennium and Millennium-II simulations -- two of the largest cosmological simulations ever performed -- to study the merger rates of galaxies and their host dark matter halos. The proposed work complements the many HST studies of galaxy mergers by advancing and refining the predicted rates from theories and simulations to allow for a more definite comparison with observations. We will focus on (1) quantifying the subhalo-subhalo merger rates as a function of a wide range of halo mass, redshift, and merger types (minor vs major; satellite vs central galaxy; mergers within a common halo vs distinct halos); and (2) understanding the relationship among halo-halo, subhalo-subhalo, and galaxy-galaxy mergers in simulations, semi-analytic models of galaxy formation, and observations. We will take advantage of the unprecedentedly large dynamic range provided by the combined results from the two Millennium simulations to test how numerical resolution affects the fate of subhalos in dense environments and the inferred subhalo and galaxy merger rates and timescales. Results from the proposed work will provide a key step towards a quantitative interpretation of HST observations of galaxy pairs and morphological fractions, as well as offer valuable guidance for merger prescriptions in galaxy catalogs that are currently being constructed on the two Millennium simulations.

COSMOLOGY 12 97189 false 0.0 0.0 false false false true false false SUPPORTED