Blue Straggler Star Populations in Globular Clusters: II. Proper-Motion Cleaned HST Catalogs of BSSs in 38 Galactic GCs

TL;DR

This paper provides new, precise proper-motion cleaned catalogs of Blue Straggler Stars in 38 globular clusters, enabling improved studies of BSS populations and their evolutionary stages.

Contribution

It introduces a homogeneous BSS selection method and publicly releases proper-motion cleaned catalogs for 38 globular clusters.

Findings

Proper motion measurements agree with previous velocity dispersion estimates.

Expanded BSS selection parameter space includes more evolved BSS stages.

Publicly available catalogs facilitate future research on BSS populations.

Abstract

We present new Blue Straggler Star (BSS) catalogs in 38 Milky Way globular clusters (GCs) based on multi-passband and multi-epoch treasury survey data from the Hubble Space Telescope. We measure precise astrometry and relative proper motions of stars in all target clusters and performed a subsequent cluster membership selection. We study the accuracy of our proper motion measurements using estimates of central velocity dispersions and find very good agreement with previous studies in the literature. Finally, we present a homogeneous BSS selection method, that expands the classic BSS selection parameter space to more evolved BSS evolutionary stages. We apply this method to the proper-motion cleaned GC star catalogs in order to define proper-motion cleaned BSS catalogs in all 38 GCs, which we make publicly available to enable further study and follow-up observations.