A unified model for the spatial and mass distribution of subhaloes

Understand

N-body simulations suggest that the substructures that survive inside dark matter haloes follow universal distributions in mass and radial number density.

• We demonstrate that a simple analytical model can explain these subhalo distributions as resulting from tidal stripping which increasingly reduces the mass of subhaloes with decreasing halo-centric distance.
• As a starting point, the spatial distribution of subhaloes of any given infall mass is shown to be largely indistinguishable from the overall mass distribution of the host halo.
• Using a physically motivated statistical description of the amount of mass stripped from individual subhaloes, the model fully describes the joint distribution of subhaloes in final mass, infall mass and radius.