Metal enrichment in supernova-dominatedhigh-z galaxies

摘要

We simulate the dynamical and chemical evolution of a forming galaxy embedded in a dark matter halo, using a three-dimensional N-body / hydrodynamic simulation code combined with stellar population synthesis. We find that a sparkling phase with multitudinous SN explosions at less than 3 × 10~8 years exhibits intense Lyman a emission from cooling shocks and well resembles Lyman a emitters (LAEs) that have been discovered at redshifts greater than three. Subsequently, the galaxy shifts to a stellar continuum radiation-dominated phase within 10~9years, which appears like Lyman break galaxies (LBGs). At the LAE phase the abundance of heavy elements is subsolar and shows strong spatial variance, but it convergently reaches a level of solar abundance at the LBG phase. Hence, it turns out that LAEs and LBGs are the on-going and major phases of chemical enrichment in a galaxy. Moreover, in order to assess the contribution of LBGs and LAEs at redshifts 3