Updated Proper Motions for Local Group Dwarf Galaxies Using Gaia Early Data Release 3
Alan W. McConnachie, Kim A. Venn
Abstract
Abstract Updated systemic proper motion estimates for 58 Milky Way satellite galaxies, based on Gaia Early Data Release 3 (EDR3), are provided. This sample is identical to that studied by McConnachie & Venn and the methodology is essentially unchanged from the original paper. The superiority of Gaia EDR3 compared to Gaia Data Release 2 means that Boötes 4, Cetus 3, Pegasus 3 and Virgo 1 have detectable systemic proper motions for the first time. For the entire galaxy sample, the median random uncertainties in the systemic proper motions are approximately a factor of two better than the previous estimates using Gaia DR2. Relevant systematic errors, which are also a factor of two smaller, dominate over random uncertainties for 25 out of the 58 objects in the sample.