The Hubble Missing Globular Cluster Survey. III. Astro-photometric catalogs, artificial-star tests, and improved absolute proper motions

TL;DR

This paper presents comprehensive astro-photometric catalogs, artificial-star tests, and improved proper motions for 34 Galactic globular clusters, enhancing data quality and enabling better understanding of their origins.

Contribution

It provides the first official catalogs with refined proper motions by combining HST and Gaia data, and updates cluster-progenitor associations.

Findings

Refined absolute proper motions with three times better precision than Gaia alone.

First-time determination of galaxy progenitor associations for five globular clusters.

Artificial-star tests to evaluate data completeness and systematics.

Abstract

The Hubble Missing Globular Cluster Survey (MGCS) has taken one of the last opportunities to complete the census of Galactic globular clusters (GCs) started by past Hubble Space Telescope (HST) programs, securing high-resolution data for 34 GCs never observed before by HST. The previous papers in the series have highlighted the astrometric and photometric potential of the project by analyzing a subsample of targets. We present, and release to the community, the official astro-photometric catalogs of the MGCS for all GCs imaged by this project. We describe the data reduction using state-of-the-art techniques designed for HST. We discuss the photometric calibration and show, for the first time, the synergy with the Gaia catalog to ensure homogeneous photometry across our data set. We compute artificial-star tests that can be used to assess systematics and the completeness level of our data. We combined HST and Gaia data to refine the absolute proper motions of our GCs, reaching a precision $\sim$3 times better than that of Gaia alone. We used these new proper motions to update (and to determine for the first time for five systems) the associations between GCs and their putative galaxy progenitors. This work continues decades-long efforts of large Treasury programs in sharing precise and accurate atlases to the community for studying GCs across a wide range of scientific endeavors.