The effect of a disc on the population of cuspy and cored dark matter substructures in Milky Way-like galaxies

We use high-resolution N-body simulations to study the effect of a galactic disc on the dynamical evolution of dark matter substructures with orbits and structural parameters extracted from the Aquarius A-2 merger tree. Satellites are modelled as equilibrium N-body realizations of generalized Hernquist profiles with 2 × 106 particles and injected in the analytical evolving host potential at zinfall, defined by the peak of their mass evolution. We select all substructures with M200(zinfall) > 108 M⊙ and first pericentric distances rp < r200. Motivated by observations of Milky Way dwarf spheroidal galaxies, we also explore satellite models with cored dark matter profiles with a fixed core size rc = 0.8 as, where as is the Hernquist scale radius. We find that models with cuspy satellites have twice as many surviving substructures at z = 0 than their cored counterparts, and four times as many if we only consider those on orbits with rp < 0.1 r200. For a given profile, adding an evolving disc potential reduces the number of surviving substructures further by a factor of &lt2 for satellites on orbits which penetrate the disc (rp < 20 kpc). For large rp, where tidal forces and the effect of the disc become negligible, the number of satellites per pericentre bin converges to similar values for all four models.