Proper motions of Milky Way globular clusters

Combining them with distance and line-of-sight velocity measurements from the literature, we analyse the distribution of globular clusters in the 6D phase space, using both position/velocity and action/angle coordinates.

The population of clusters in the central 10kpc has a mean rotational velocity reaching 50-80km/s, and a nearly isotropic velocity dispersion 100-120km/s, while in the outer galaxy, the cluster orbits are strongly radially anisotropic. We confirm a concentration of clusters at high radial action in the outer region of the Galaxy. Finally, we explore a range of equilibrium distribution function-based models for the entire globular cluster system, and the information they provide about the potential of the Milky Way.