RR Lyrae Stars In Stellar Streams with Gaia: The Escapers

TL;DR

This study uses Gaia EDR3 data to identify RR Lyrae stars potentially escaped from seven globular clusters by analyzing proper motions, distances, and stellar properties, revealing 24 candidate escaped stars.

Contribution

First comprehensive search combining Gaia EDR3 and other catalogs to find RR Lyrae stars escaped from specific globular clusters.

Findings

Identified 24 RR Lyrae stars likely escaped from seven GCs.

Cross-matched Gaia DR2, Catalina Sky Survey, and Gaia EDR3 catalogs.

Used distance and metallicity relations to estimate star origins.

Abstract

We attempt to identify RR Lyrae (RRL) stars in stellar streams that might have escaped from seven globular clusters (GCs) based on proper motions, distances, color-magnitude diagrams, and other properties extracted from the Gaia Early Data Release 3 (EDR3) database. Specifically, we cross-match two large RRL stars catalogs (from Gaia DR2 and Catalina Sky Survey) with each other and with the EDR3 database and we end up with a sample of ~ 150,000 unique RRL stars. We calculate distances to RRL stars using the (M_G-[Fe/H]) and (M_V-[Fe/H]) absolute magnitude-metallicity relations and adopt [Fe/H] values for the GCs from different spectroscopic studies. We also constrain our search in areas where stellar streams associated with GCs were previously suggested or identified in other studies. We identify 24 RRL stars that might have escaped from the following seven GCs: Palomar 13 (Pal 13), NGC 6341 (M92), NGC 5904 (M5), NGC 5466, NGC 1261, NGC 288, and NGC 1851. We list our findings in Table 2.