2017MNRAS.465L..59E

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 x 10⁶ particles and injected in the analytical evolving host potential at z_infall, defined by the peak of their mass evolution. We select all substructures with M₂₀₀(z_infall) >= 10⁸ M_☉ and first pericentric distances r_p < 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 r_c = 0.8 a_s, where a_s 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 r_p <= 0.1 r₂₀₀. For a given profile, adding an evolving disc potential reduces the number of surviving substructures further by a factor of <=2 for satellites on orbits which penetrate the disc (r_p <= 20 kpc). For large r_p, 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.