The metallicity of void dwarf galaxies
  The current Lambda CDM cosmological model predicts that galaxy evolution
proceeds more slowly in lower density environments, suggesting that voids are a
prime location to search for relatively pristine galaxies that are
representative of the building blocks of early massive galaxies. To test the
assumption that void galaxies are more pristine, we compare the evolutionary
properties of a sample of dwarf galaxies selected specifically to lie in voids
with a sample of similar isolated dwarf galaxies in average density
environments. We measure gas-phase oxygen abundances and gas fractions for
eight dwarf galaxies (M_r > -16.2), carefully selected to reside within the
lowest density environments of seven voids, and apply the same calibrations to
existing samples of isolated dwarf galaxies. We find no significant difference
between these void dwarf galaxies and the isolated dwarf galaxies, suggesting
that dwarf galaxy chemical evolution proceeds independent of the large-scale
environment. While this sample is too small to draw strong conclusions, it
suggests that external gas accretion is playing a limited role in the chemical
evolution of these systems, and that this evolution is instead dominated mainly
by the internal secular processes that are linking the simultaneous growth and
enrichment of these galaxies.
