  We present first results from three-dimensional hydrodynamic simulations of
the high redshift formation of dwarf galaxies. The simulations use an Eulerian
adaptive mesh refinement technique to follow the non-equilibrium chemistry of
hydrogen and helium with cosmological initial conditions drawn from a popular
Lambda-dominated CDM model. We include the effects of reionization using a
uniform radiation field, a phenomenological description of the effect of star
formation and, in a separate simulation, the effects of stellar feedback. The
results highlight the effects of stellar feedback and photoionization on the
baryon content and star formation of galaxies with virial temperatures of
approximately 10^4K. Dwarf sized dark matter halos that assemble prior to
reionization are able to form stars. Most halos of similar mass that assemble
after reionization do not form stars by redshift of three. Dwarf galaxies that
form stars show large variations in their gas content because of stellar
feedback and photoionization effects. Baryon-to-dark matter mass ratios are
found to lie below the cosmic mean as a result of stellar feedback. The
supposed substructure problem of CDM is critically assessed on the basis of
these results. The star formation histories modulated by radiative and stellar
feedbacks are discussed. In addition, metallicities of individual objects are
shown to be naturally correlated with their mass-to-light ratios as is also
evident in the properties of local dwarf galaxies.
