Simulations of Cosmic Chemical Enrichment
We simulate cosmic chemical enrichment with a hydrodynamical Model including supernova and hypernova feedback. We find that the majority of stars in present-day massive, galaxies formed in much Smaller galaxies at high redshifts, despite their late assembly times. As a result, the observed cosmic star formation rates and stellar density evolution are well reproduced simultaneously. The hypernova feedback drives galactic outflows efficiently in low-mass galaxies, and these winds eject heavy elements into the intergalactic medium. The ejected baryon fraction is larger for less massive galaxies and correlates well with Stella], metallicity. The observed mass-metallicity relation is well reproduced as a result of the mass-dependent galactic winds.