DELVE-ing into the Milky Way's Globular Clusters: Assessing extra-tidal features in NGC 5897, NGC 7492, and testing detectability with deeper photometry

TL;DR

This study systematically searches for and analyzes extra-tidal features around 19 globular clusters using DELVE survey data, discovering new features and assessing their detectability with future LSST observations.

Contribution

It reports the discovery of new extra-tidal envelopes around NGC 5897 and NGC 7492 and evaluates how future surveys can improve their detection.

Findings

New extra-tidal envelope around NGC 5897

Tentative extended envelope around NGC 7492

LSST will improve detection but requires additional foreground removal methods

Abstract

Extra-tidal features around globular clusters (GCs) are tracers of their disruption, stellar stream formation, and their host's gravitational potential. However, these features remain challenging to detect due to their low surface brightness. We conduct a systematic search for such features around 19 GCs in the DECam Local Volume Exploration (DELVE) survey Data Release 2, discovering a new extra-tidal envelope around NGC 5897 and find tentative evidence for an extended envelope surrounding NGC 7492. Through a combination of dynamical modeling and analyzing synthetic stellar populations, we demonstrate these envelopes may have formed through tidal disruption. We use these models to explore the detectability of these features in the upcoming Legacy Survey of Space and Time (LSST), finding that while LSST's deeper photometry will enhance detection significance, additional methods for foreground removal like proper motions or metallicities may be important for robust stream detection. Our results both add to the sample of globular clusters with extra-tidal features and provide insights on interpreting similar features in current and upcoming data.