Abstract
One of the key processes driving galaxy evolution during the Cosmic Dawn is
supernova feedback. This likely helps regulate star formation inside of
galaxies, but it can also drive winds that influence the large-scale
intergalactic medium. Here, we present a simple semi-analytic model of
supernova-driven galactic winds and explore the contributions of different
phases of galaxy evolution to metal enrichment in the high-redshift (z > 6)
Universe. We show that models calibrated to the observed galaxy luminosity
function at z~6-8 have filling factors ~1% at z~6 and ~0.1% at z~12, with
different star formation prescriptions providing about an order of magnitude
uncertainty. Despite the small fraction of space filled by winds, these
scenarios still provide more than enough enriched volume to explain the
observed abundance of metal-line absorbers in quasar spectra at z > 5. We also
consider enrichment through winds driven by Pop III star formation in
minihaloes. We find that these can dominate the total filling factor at z > 10
and even compete with winds from normal galaxies at z~6, at least in terms of
the total enriched volume. But these regions have much lower overall
metallicities, because each one is generated by a small burst of star
formation. Finally, we show that Compton cooling of these supernova-driven
winds at z > 6 has only a small effect on the cosmic microwave background.
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