# HST proper motions in Galactic globular clusters

## TL;DR

This paper presents high-precision proper motion catalogs for 22 Galactic globular clusters, enabling new insights into their internal dynamics, distances, masses, and stellar populations.

## Contribution

It provides the first direct measurements of radial anisotropy, dynamical distances, M/L ratios, and masses of blue-straggler stars across a large GC sample.

## Key findings

- First directly-measured radial anisotropy profiles for many GCs.
- Dynamical distance and M/L ratio estimates for numerous GCs.
- Mass measurements for hundreds of blue-straggler stars.

## Abstract

Proper motions (PMs) are crucial to fully understand the internal dynamics of globular clusters (GCs). To that end, the Hubble Space Telescope (HST) Proper Motion (HSTPROMO) collaboration has constructed large, high-quality PM catalogues for 22 Galactic GCs. We highlight some of our exciting recent results: the first directly-measured radial anisotropy profiles for a large sample of GCs; the first dynamical distance and mass-to-light (M/L) ratio estimates for a large sample of GCs; and the first dynamically-determined masses for hundreds of blue-straggler stars (BSSs) across a large GC sample.