Substructure in the stellar halos of the Aquarius simulations
  We characterize substructure in the simulated stellar halos of Cooper et al.
(2010) which were formed by the disruption of satellite galaxies within the
cosmological N-body simulations of galactic halos of the Aquarius Project.
These stellar halos exhibit a wealth of tidal features: broad overdensities and
very narrow faint streams akin to those observed around the Milky Way. The
substructures are distributed anisotropically on the sky, a characteristic that
should become apparent in the next generation of photometric surveys. The
normalized RMS of the density of stars on the sky appears to be systematically
larger for our halos compared to the value estimated for the Milky Way from
main sequence turn-off stars in the Sloan Digital Sky Survey. We show that this
is likely to be due in part to contamination by faint QSOs and redder main
sequence stars, and might suggest that ~10% of the Milky Way halo stars have
formed in-situ.
