A unified model for the spatial and mass distribution of subhaloes
Abstract
Nbody 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 halocentric 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. As a result, it can be used to predict several derived distributions involving combinations of these quantities including, but not limited to, the universal subhalo mass function, the subhalo spatial distribution, the gravitational lensing profile, the dark matter annihilation radiation profile and boost factor. This model clarifies a common confusion when comparing the spatial distributions of galaxies and subhaloes, the socalled antibias, as a simple selection effect. We provide a PYTHON code SUBGEN for populating haloes with subhaloes at http://icc.dur.ac.uk/data/.
 Publication:

Monthly Notices of the Royal Astronomical Society
 Pub Date:
 April 2016
 DOI:
 10.1093/mnras/stv2900
 arXiv:
 arXiv:1509.02175
 Bibcode:
 2016MNRAS.457.1208H
 Keywords:

 galaxies: haloes;
 dark matter;
 Astrophysics  Cosmology and Nongalactic Astrophysics;
 Astrophysics  Astrophysics of Galaxies
 EPrint:
 MNRAS accepted version. Minor changes for clarity