We revisit the formation and evolution of the first galaxies using new
hydrodynamic cosmological simulations with the ART code. Our simulations
feature a recently developed model for H2 formation and dissociation, and a
star formation recipe that is based on molecular rather than atomic gas. Here,
we develop and implement a recipe for the formation of metal-free Population
III stars in galaxy-scale simulations that resolve primordial clouds with
sufficiently high density. We base our recipe on the results of prior zoom-in
simulations that resolved the protostellar collapse in pre-galactic objects. We
find the epoch during which Pop III stars dominated the energy and metal budget
of the first galaxies to be short-lived. Galaxies which host Pop III stars do
not retain dynamical signatures of their thermal and radiative feedback for
more than 10^8 yr after the lives of the stars end in pair-instability
supernovae, even when we consider the maximum reasonable efficiency of the
feedback. Though metals ejected by the supernovae can travel well beyond the
virial radius of the host galaxy, they typically begin to fall back quickly,
and do not enrich a large fraction of the intergalactic medium. Galaxies with
total mass in excess of 3 x 10^6 Msun re-accrete most of their baryons and
transition to metal-enriched Pop II star formation.Comment: 13 pages, 9 figures, published in Ap
