Extended Press-Schechter theory and the density profiles of dark matter haloes

Abstract

An inside-out model for the formation of haloes in a hierarchical clustering scenario is studied. The method combines the picture of the spherical infall model and a modification of the extended Press-Schechter theory. The mass accretion rate of a halo is defined to be the rate of its mass increase due to minor mergers. The accreted mass is deposited at the outer shells without changing the density profile of the halo inside its current virial radius. We applied the method to a flat $ΛCDM$ Universe. The resulting density profiles are compared to analytical models proposed in the literature, and a very good agreement is found. A trend is found of the inner density profile becoming steeper for larger halo mass, that also results from recent N-body simulations. Additionally, present-day concentrations as well as their time evolution are derived and it is shown that they reproduce the results of large cosmological N-body simulations.