Early metal enrichment and Lyman α emission

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 x 10(8) years exhibits intense Lyman alpha emission from cooling shocks and well resembles Lyman a emitters (LAEs) that have been recently discovered at redshifts greater than three. Subsequently, the galaxy shifts to a stellar continuum radiation-dominated phase within 10(9) years, 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. (c) 2005 Elsevier B.V. All rights reserved.