The self-enrichment of galactic halo globular clusters - A clue to their formation?

We present a model of globular cluster self-enrichment. In the protogalaxy, cold and dense clouds embedded in the hot protogalactic medium are assumed to be the progenitors of galactic halo globular clusters. The massive star s of a first generation of metal-free stars, born in the central areas of t he proto-globular cluster clouds, explode as Type II supernovae. The associ ated blast waves trigger the expansion of a supershell, sweeping all the ma terial of the cloud, and the heavy elements released by these massive stars enrich the supershell. A second generation of stars is born in these compr essed and enriched layers of gas. These stars can recollapse and form a glo bular cluster. This work aims at revising the most often encountered argume nt against self-enrichment, namely the presumed ability of a small number o f supernovae to disrupt a proto-globular cluster cloud. We describe a model of the dynamics of the supershell and of its progressive chemical enrichme nt. We show that the minimal mass of the primordial cluster cloud required to avoid disruption by several tens of Type II supernovae is compatible wit h the masses usually assumed for proto-globular cluster clouds. Furthermore , the corresponding self-enrichment level is in agreement with halo globula r cluster metallicities.