Chemical Abundance Patterns and the Early Environment of Dwarf Galaxies
  Recent observations suggest that abundance pattern differences exist between
low metallicity stars in the Milky Way stellar halo and those in the dwarf
satellite galaxies. This paper takes a first look at what role the early
environment for pre-galactic star formation might have played in shaping these
stellar populations. In particular, we consider whether differences in
cross-pollution between the progenitors of the stellar halo and the satellites
could help to explain the differences in abundance patterns. Using an N-body
simulation, we find that the progenitor halos of the main halo are primarily
clustered together at z=10 while the progenitors of the satellite galaxies
remain on the outskirts of this cluster. Next, analytically modeled
supernova-driven winds show that main halo progenitors cross-pollute each other
more effectively while satellite galaxy progenitors remain more isolated. Thus,
inhomogeneous cross-pollution as a result of different high-z spatial locations
of each system's progenitors can help to explain observed differences in
abundance patterns today. Conversely, these differences are a signature of the
inhomogeneity of metal enrichment at early times.
