The Evolution of Globular Cluster Systems in Galaxies

H. Baumgardt

Abstract:
This work considers the initial distribution and dynamical evolution of globular cluster systems in galaxies. Here, globular cluster systems start with power-law mass functions with slopes similar to what is observed for the young globular clusters seen in merging and interacting galaxies. Initially a number of globular clusters is distributed according to a specified density-law. The orbits of the clusters are then integrated numerically, allowing different destruction mechanisms to dissolve them. The destruction mechanisms are treated by means of a semianalytic me thod, which allows a large number of different initial conditions to be examined. The evolution of the globular clusters is followed in three different galaxies. In comparing the surviving distribution to the observed, we show that our model can reproduce several aspects of present day globular cluster systems. The Gaussian luminosity distribution observed for the globular clusters of the Milky Way and M87 is a product of the preferential destruction of low-mass clusters through internal relaxation. Furthermore, it is examined what portion of stars in the different galaxies were formed in globular clusters. Finally, comparing the evolution of globular clusters in different galaxies, we investigate the reliability of the luminosity profile of a globular cluster system as a distance indicator.


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