The structure of halos in Self-Interacting Cold Dark Matter models

Abstract

High-resolution numerical simulations were performed to study the structure and substructure of Milky Way- and cluster-sized halos in a LCDM cosmology with self-interacting (SI) dark particles, where the particle cross section, +AFw-sig, is assumed constant or inversely proportional to the relative velocity. We conclude that the cuspy halo problem at galaxy scales of the LCDM cosmogony can be solved in the latter case. In this case, the inner density of galaxy-cluster halos is only slightly affected by the SI, resulting in agreement with observational constraints. At the same time, the subhalo population in galaxy and cluster SI-CDM halos remains roughly similar to that seen on collisionless CDM halos.