Constraining the distribution of dark matter in dwarf spheroidal
  galaxies with stellar tidal streams
  We use high-resolution N-body simulations to follow the formation and
evolution of tidal streams associated to dwarf spheroidal galaxies (dSphs). The
dSph models are embedded in dark matter (DM) haloes with either a
centrally-divergent 'cusp', or an homogeneous-density 'core'. In agreement with
previous studies, we find that as tides strip the galaxy the evolution of the
half-light radius and the averaged velocity dispersion follows well-defined
tracks that are mainly controlled by the amount of mass lost. Crucially, the
evolutionary tracks behave differently depending on the shape of the DM
profile: at a fixed remnant mass, dSphs embedded in cored haloes have larger
sizes and higher velocity dispersions than their cuspy counterparts. The
divergent evolution is particularly pronounced in galaxies whose stellar
component is strongly segregated within their DM halo and becomes more
disparate as the remnant mass decreases. Our analysis indicates that the DM
profile plays an important role in defining the internal dynamics of tidal
streams. We find that stellar streams associated to cored DM models have
velocity dispersions that lie systematically above their cuspy counterparts.
Our results suggest that the dynamics of streams with known dSph progenitors
may provide strong constraints on the distribution of DM on the smallest
galactic scales.
