The initial distribution and evolution of globular cluster systems

This work considers the evolution of globular cluster systems in galaxies. Here globular cluster systems start with power-law mass functions φ ∼ M−α with slopes around 2.0, similar to what has been observed for the young luminous clusters seen in merging and interacting galaxies. We then follow the orbits of the clusters through their parent galaxy, allowing various destruction mechanisms to dissolve them. In comparing the surviving distribution to the observed one, we show that our model can reproduce several aspects of present day globular cluster systems. This method is employed to the globular clusters of the Milky Way and M87. In the case of the Milky Way we obtain luminosity distributions, which depend on the galactocentric distance in a way similar to what is observed. We also observe a change in the velocity distribution of the globular cluster system,which predicts a different kinematical state of the surviving halo clusters compared to the halo stars. The final luminosity function of the globular cluster system in M87 can differ from the one found for the Milky Way clusters, which casts doubt on the use of globular cluster luminosity functions to measure distances. We also discuss some implications of our results for the dynamical history of M87.