The merger rates and mass assembly histories of dark matter haloes in the two Millennium simulations

We construct merger trees of dark matter haloes and quantify their merger rates and mass growth rates using the joint data set from the Millennium and Millennium-II simulations. The finer resolution of the Millennium-II simulation has allowed us to extend our earlier analysis of halo merger statistics to an unprecedentedly wide range of descendant halo mass (1010≲<it>M</it><inf>0</inf>≲ 1015 M<inf>⊙</inf>), progenitor mass ratio (10−5≲ξ≤ 1) and redshift (0 ≤<it>z</it>≲ 15). We update our earlier fitting form for the mean merger rate <it>per halo</it> as a function of…

• SA
  Smithsonian Astrophysical Observatory