Mapping substructures in dark matter haloes

Abstract

We present a detailed study of the real and integrals-of-motion space distributions of a disrupting satellite obtained from a fully self-consistent high-resolution cosmological simulation of a galaxy cluster. The satellite has been re-simulated using various analytical halo potentials, and we find that its debris appears as a coherent structure in integrals-of-motion space in all models ('live' and analytical potential), although the distribution is significantly smeared for the live host halo. The primary mechanism for the dispersion is the mass growth of the host. However, when quantitatively comparing the effects of 'live' and time-varying host potentials, we conclude that not all of the dispersion can be accounted for by the steady growth of the mass of the host.We ascribe the remaining discrepancies to additional effects in the 'live' halo such as non-sphericity of the host and interactions with other satellites which have not been modelled analytically. © 2005 RAS.