HST Astrometric Survey of Magellanic Clouds Star Clusters (HAMSTERS)

The Hubble Space Telescope (HST) Astrometric Survey of Magellanic Clouds Star Clusters (HAMSTERS) presents astro-photometric catalogs for 23 massive star clusters within the Large Magellanic Cloud using multi-epoch HST observations. For 19 clusters, data from a dedicated HST program (GO-16748) add an additional epoch of observations for proper motion determinations. The authors calculated stellar proper motions by combining archival data from the ACS/WFC and WFC3/UVIS instruments with observations from program GO-16748. This sample of clusters was complemented with four more clusters that have already-existing observations in the HST archive suitable for proper motion calculations. The used data sets span time baselines between 4.7 years and 18.2 years, depending on the cluster. Bright well-measured stars reach nominal proper motion precisions of 55 micro-arcseconds per year down to 11 micro-arcseconds per year. HST's high resolution and sensitivity allowed to determine proper motions for a total of 855,000 sources, distributed among the 23 clusters within the sample.