Dependence of the Inner DM Profile on the Halo Mass

I compare the density profile of dark matter (DM) halos in cold dark matter (CDM) N-body simulations with 1 h Mpc, 32 h Mpc, 256 h Mpc and 1024 h Mpc box sizes. I compare the profiles when the most massive halos are composed of about 10 DM particles. The DM density profiles of the halos in the 1 h Mpc box at redshift z ∼ 10 show systematically shallower cores with respect to the corresponding halos in the 32 h Mpc simulation at z ∼ 3 that have masses, Mdm, typical of the Milky Way and are fitted by a NFW profile. The DM density profiles of the halos in the 256 h Mpc box at z ∼ 0 are consistent with having steeper cores than the corresponding halos in the 32 h Mpc simulation, but higher mass resolution simulations are needed to strengthen this result. Combined, these results suggest that the density profile of DM halos is not universal, presenting shallower cores in dwarf galaxies and steeper cores in clusters. More work is needed to validate this finding at z = 0. Physically the result sustains the hypothesis that the mass function of the accreting satellites determines the inner slope of the DM profile. But the result can also be interpreted as a trend with the dynamical state in the assembly process of halos of different mass. In comoving coordinates, r, the profile