Halo evolution in a cosmological environment

Abstract

We study the formation and evolution of the dark matter halos in a LCDM model. The dynamics of 16.8 million DM particles is followed numerically in a box of 60 Mpc/h with the dynamic range of 32,000 in spatial resolution. The high resolution of the simulation allows us to examine evolution of both isolated and satellite halos in a representative volume. We present results on the evolution of velocity function of DM halos, compare it with the Press-Schechter function and discuss the evolution of power spectrum of matter and halo distributions. The mass evolution of isolated virialized objects determined from the simulation is in good agreement with predictions of the extended Press-Schechter models. However, satellite halos evolve very different: for some of them the mass decreases with time, which happens if the halos fall into clusters or groups. We discuss the dependence of the correlation function of halo populations on their environment and merging history.