Modelling of Proper Motions in Globular Clusters
Abstract
Globular clusters come in a variety of flavours; their different components and different evolution histories leave imprints on their internal dynamics, which makes dynamical modelling a valuable tool for understanding their properties. Velocity dispersion profiles and mass profiles are key when investigating energy equipartition and core collapse or when hunting for intermediate mass black holes. Proper motion data are particularly useful as they provide two velocity components, which allows us to determine anisotropy profiles as well. From analyses by Bellini et al. carried out in the context of the HST Proper Motion (HSTPROMO) collaboration we now have HST proper motion data for some two dozen Galactic globular clusters. Each dataset typically contains proper motion data with accuracies of order 1 km/s for tens of thousands of stars within the central arcminute. We have developed new modelling techniques specifically designed to work with large, high-quality, discrete datasets of this nature, which we have successfully tested and applied to omega Centauri. We will briefly discuss our modelling efforts and then present some preliminary results for the new HST datasets, including velocity dispersion profiles, mass profiles, and energy equipartition.
- Publication:
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American Astronomical Society Meeting Abstracts #223
- Pub Date:
- January 2014
- Bibcode:
- 2014AAS...22343301W