On star formation in primordial protoglobular clouds

Using a new physical model for star formation, we have tested the possibility that globular clusters (GCs) are formed from primordial mass fluctuations, the mass scale of which (108–109M⊙) is selected out of a cold dark matter spectrum by the mechanism of non-equilibrium formation of H2. We show that such clouds are able to convert about 0.002 of their total mass into a bound system (a GC) and about 0.02 into halo stars. The metal-enriched gas is dispersed from the GC by supernova explosions and forms the Galactic disc. The mass ratios between GCs, halo and disc depend on the predicted initial mass function which is a consequence of the universal statistics of fluid turbulence. They also depend on the ratio of baryonic to non-baryonic mass, Xb, and are comparable to the values observed in typical spiral galaxies for Xb≈0.1–0.2. The computed mass and radius for a GC (5 × 105 M⊙ and 30 pc) are in good agreement with the average values in the Galaxy. The model predicts an exponential cut-off in the stellar initial mass function below 0.2 M⊙ in GCs and 0.7 M⊙ in the halo. The reasonably massive star formation in primordial clouds leads to a large number of supernovae and to a high blue luminosity during the first 2 Gyr of the life of the Galaxy.