Near-Field Cosmology with Metal-Poor Stars
  The oldest, most metal-poor stars in the Galactic halo and satellite dwarf
galaxies present an opportunity to explore the chemical and physical conditions
of the earliest star forming environments in the Universe. We review the fields
of stellar archaeology and dwarf galaxy archaeology by examining the chemical
abundance measurements of various elements in extremely metal-poor stars. Focus
on the carbon-rich and carbon-normal halo star populations illustrates how
these provide insight into the Population III star progenitors responsible for
the first metal enrichment events. We extend the discussion to near-field
cosmology, which is concerned with the formation of the first stars and
galaxies and how metal-poor stars can be used to constrain these processes.
Complementary abundance measurements in high-redshift gas clouds further help
to establish the early chemical evolution of the Universe. The data appear
consistent with the existence of two distinct channels of star formation at the
earliest times.
