HST Atlases of Cluster KinematicS (HACKS)

A number of studies based on data collected by the Hubble Space Telescope (HST) GO-13297 program “HST Legacy Survey of Galactic Globular Clusters: Shedding UV Light on Their Populations and Formation" have investigated the photometric properties of a large sample of Galactic globular clusters and revolutionized our understanding of their stellar populations. In this project, the authors expand previous studies by focusing on the stellar clusters’ internal kinematics. The authors computed proper motions for stars in 56 globular and one open clusters by combining the GO-13297 images with archival HST data. The astro-photometric catalogs released with this paper represent the most complete and homogeneous collection of proper motions of stars in the cores of stellar clusters to date, and expand the information provided by the current (and future) Gaia data releases to much fainter stars and into the crowded central regions. At the dawn of a new era in astronomy with the first light of the James Webb Space Telescope (JWST), the legacy that these proper-motion catalogs offer is further enhanced, since they can serve as an important astrometric benchmark for JWST-based data reduction and tools.