The First Supernova Explosions in the Universe

We investigate the supernova explosions that end the lives of massivePopulation III stars in low-mass minihalos (M~10^6 M_sun) at redshifts z~20.Employing the smoothed particle hydrodynamics method, we carry out numericalsimulations in a cosmological set-up of pair-instability supernovae withexplosion energies of E_SN=10^51 and 10^53 ergs. We find that the moreenergetic explosion leads to the complete disruption of the gas in theminihalo, whereas the lower explosion energy leaves much of the halo intact.The higher energy supernova expels > 90% of the stellar metals into a region ~1kpc across over a timescale of 3-5 Myr. Due to this burst-like initial starformation episode, a large fraction of the universe could have been endowedwith a metallicity floor, Z_min>10^-4 Z_sun, already at z>15.Comment: Published in ApJ Letter