Nonlinear evolution of cosmological structures in nonthermal production of dark matter model

Abstract

The nonthermal production of dark matter can provide a large free-streaming length, under which the density fluctuations would be suppressed severely. We explore the nonlinear evolution of cosmological structures in the dark energy dominated model with nonthermal dark matter (NTDM). With the help of -body simulations, we study the nonlinear matter power spectrum, the halo mass function, and the halo density profiles. It is demonstrated that NTDM produces a far lesser number of the subgalactic structures than that of the conventional cold dark matter (CDM). We also find that the density profiles of the low-mass halos in the NTDM model are flat, in contrast to the cuspy cores predicted by the CDM model. The -body simulations show that the inconsistent predictions of the standard model on the galactic and subgalactic scales may be accounted for by the nonthermal mechanism for the production of dark matter.