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Yuexing Li (Columbia University), M.-M. Mac Low (American Museum of Natural History), R. Klessen (Astrophysikalisches Institut Potsdam, Germany)
I present high-resolution (million particle or more) N-body/SPH simulations of star cluster formation in a wide range of isolated disk galaxies. Our models quantitatively reproduce not only observed global and local Schmidt laws, but also observed star formation thresholds in disk galaxies. These results suggest that the dominant physical mechanism determining the star formation rate is just the strength of gravitational instability, with feedback primarily functioning to maintain a roughly constant effective sound speed. We then use the same technique to study star 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. The merging galaxies show a strong starburst, in sharp contrast to their isolated progenitors. Most star clusters form in tidal features. They are large enough to give rise to globular clusters. The merger remnant is an elliptical galaxy. Clusters with different mass or age have different radial distributions in the galaxy. Our results show that the high specific frequency and bimodal distribution of metallicity observed in the globular cluster systems of elliptical galaxies are natural products of gas-rich mergers.
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Bulletin of the American Astronomical Society, 36 5
© 2004. The American Astronomical Society.