Searching Extra-tidal Features around the Globular Cluster Whiting 1

TL;DR

This study investigates the spatial connection between the globular cluster Whiting 1 and the Sagittarius dwarf galaxy, revealing tentative tidal tails aligned with its orbit, suggesting debris stripping by the Milky Way.

Contribution

First detection of extended tidal features around Whiting 1 using deep imaging surveys, supporting its origin in the Sagittarius dwarf galaxy.

Findings

Detected round-shaped extra-tidal features with possible tails.

Tails extend 0.1-0.2 degrees along the orbit.

Features align with the orbital path of Sgr dSph.

Abstract

Whiting 1 is a faint and young globular cluster in the halo of the Milky Way, and was suggested to have originated in the Sagittarius spherical dwarf galaxy (Sgr dSph). In this paper, we use the deep DESI Legacy Imaging Surveys to explore tentative spatial connection between Whiting 1 and the Sgr dSph. We redetermine the fundamental parameters of Whiting 1 and use the best-fitting isochrone (age $\tau$=6.5 Gyr, metalicity Z=0.005 and $\rm d_{\odot}$=26.9 kpc) to construct a theoretical matched filter for the extra-tidal features searching. Without any smooth technique to the matched filter density map, we detect a round-shape feature with possible leading and trailing tails on either side of the cluster. This raw image is not totally new compared to old discoveries, but confirms that no more large-scale features can be detected under a depth of r<=22.5 mag. In our results, the whole feature stretches 0.1-0.2 degree along the orbit of Whiting 1, which gives a much larger area than the cluster core. The tails on both sides of the cluster align along the orbital direction of the Sgr dSph as well as the cluster itself, which implies that these debris are probably stripped remnants of Whiting 1 by the Milky Way.