On the formation and evolution of the globular cluster Omega Centauri

Abstract

By means of N-body/hydrodynamical simulations we model the evolution of a primordial 10^{8} solar masses density peak which ends up in an object closely resembling the present day globular cluster Omega Centauri. We succeed to reproduce the main features of the cluster, namely the structure, kinematics and metallicity distribution. We suggest that Omega Centauri might be a cosmological dwarf elliptical, formed at high redshift, evolved in isolation and self-enriched, and eventually fallen inside the potential well of the Milky Way, in agreement with the Searle-Zinn (1978) paradigm for galactic globular clusters formation. We finally suggest that Omega Centauri is probably surrounded by an extended Dark Matter (DM) halo, for which no observational evidence is at present available. We expect that signatures, if any, of the DM halo can be found in the kinematics of stars outside about 20 arcmin.