  If the favored hierarchical cosmological model is correct, then the Milky Way
system should have accreted and subsequently tidally destroyed ~100 low-mass
galaxies in the past ~12 Gyr. We model this process using a hybrid
semi-analytic plus N-body approach and show that the disrupted systems lead
naturally to stellar halos with masses and density profiles much like the
stellar halo of our own Galaxy. We present predictions for the properties of
stellar halos and show that ours is likely dominated by substructure beyond
\~50kpc and more spatially smooth within that radius. The average stellar halo
density profile is expected to drop off with radius more quickly than that of
the dark matter because the stellar halo is formed from the most tightly bound
material in infalling systems, while the majority of the accreted dark matter
is stripped and deposited at larger radii. We argue that stars associated with
the inner halo should be quite different chemically from stars in surviving
satellites and also different from stars in the outer halo or those liberated
in recent disruption events. We discuss how deep halo surveys and chemical
probes may be useful tools for uncovering evidence of accretion. Searches of
this kind offer a direct test of whether cosmology is indeed hierarchical on
small scales.
