Starbirth in Galaxy Collisions

Abstract

Young, massive star clusters are the most notable and significant end products of violent star-forming episodes triggered by galaxy collisions, mergers, and close encounters. Their contribution to the total luminosity induced by such extreme conditions dominates, by far, the overall energy output due to the gravitationally-induced star formation. The general characteristics of these newly-formed clusters (such as their masses, luminosities, and sizes) suggest that at least a fraction may eventually evolve into equal, or perhaps slightly more massive, counterparts of the abundant old globular cluster systems in the local Universe. Establishing whether or not such an evolutionary connection exists requires our detailed knowledge of not only the physics underlying the evolution of "simple" stellar populations, but also that of cluster disruption in the time-dependent gravitational potentials of interacting galaxies. Initial results seem to indicate that proto-globular clusters do indeed continue to form today, which would support hierarchical galaxy formation scenarios.