Formation of Globular Clusters in Galaxy Mergers

Abstract

We present a high-resolution simulation of globular cluster formation in a galaxy merger. For the first time in such a simulation, individual star clusters are directly identified and followed on their orbits. We quantitatively compare star formation in the merger to that in the unperturbed galaxies. The merging galaxies show a strong starburst, in sharp contrast to their isolated progenitors. Most star clusters form in the tidal features. With a mass range of 5×105-5×106 Msolar, they are identified as globular clusters. The merger remnant is an elliptical galaxy. Clusters with different masses or ages have different radial distributions in the galaxy. Our results show that the high specific frequency and bimodal distribution of metallicity observed in elliptical galaxies are natural products of gas-rich mergers, supporting a merger origin for the ellipticals and their globular cluster systems.