Feedback from the First Supernovae in Protogalaxies: The Fate of the Generated Metals

We investigate the chemo-dynamical effects of multiple supernova explosionsin the central region of primordial galaxies using three-dimensionalhydrodynamical simulations of the inhomogenous interstellar medium down toparsec-scales. We find that the final protogalactic structure and metaldistribution depend strongly on the number of SNe. Specifically, 1) 1000 SNeafter an instantaneous burst of star formation are sufficient to almostcompletely blow away the gas in these systems, whereas 2) 100 SN explosionstrigger the collapse of the protogalactic cloud, leading to the formation of acold, dense clumpy disk (n > 300 cm^-3) with metallicity, Z = 4 10^-4 Z_sun.These results imply that the metallicity of the ``second generation'' of starscould be Z ~ 10^-4 Z_sun, and that the environment to form metal-free stars inprotogalaxies may be lost relatively quickly (< 10^7 yr) after the first burstof Z=0 star formation. The recently discovered ultra-metal-poor star(Christlieb et al. 2002) may represent surviving members of suchsecond-generation star formation.Comment: 6 pages, 3 figures. Accepted for publication in ApJ, v. 591 (July 1, 2003