Primordial Star Forming Regions in a CDM Universe

Abstract

We developed a three-dimensional 2-level hierarchical cosmological code with a realistic and robust treatment of multi-species non-equilibrium ionization and radiative cooling processes, and use it to investigate primordial star forming regions that originate from high-σperturbations in a standard CDM dominated cosmology. We find it is possible to produce gravitationally bound and cooled structures at very high redshift (z ~ 40) with baryonic masses as small as ~1000Ms. The molecular hydrogen formation in these small scale structures follows very well the analytical predictions of Abel (1995) and Tegmark et al. (1996). We also discuss the minimum mass that cosmological structures must have in order to be able to cool and collapse.

4 pages, with one figure that prints in color. To appear in the proceedings of the 7th Annual Astrophysics Conference in Maryland, STAR FORMATION, NEAR AND FAR, eds. Stephen S. Holt and Lee G. Mundy. This paper and some of the referenced articles are also available at http://lca.ncsa.uiuc.edu/~tom/PGas/bib.html