“ Mergers of Dark Matter Halos and Galaxies in Lambda-CDM Cosmology"

In a cold dark matter universe, galaxies and their host dark matter halos gain mass primarily through mergers with other galaxies. Having an accurate description of the mergers of dark matter haloes is therefore a key first step in understanding galaxy formation and growth.
I will describe recent analyses of merger trees constructed from the Millennium simulation and present a nearly universal formula for the merger rates of dark matter halos over a broad range of masses and redshifts. The connection to galaxy mergers, the Press-Schechter model, and
the Smoluchowski coagulation equation will be discussed.