A search for stellar structures around nine outer halo globular clusters in the Milky Way

ABSTRACT We use deep imaging from the Dark Energy Camera to explore peripheral regions of nine globular clusters in outer halo Milky Way. Apart Whiting 1 and NGC 7492, which are projected against Sagittarius stream, we see no evidence for adjacent stellar populations indicate any these is associated with coherent tidal debris a destroyed host dwarf. also find tails around our sample; however, both 1904 6981 appear possess envelopes. Motivated by slew recent Gaia-based discoveries, compile sample robust detections extra-tidal structure, search correlations orbital properties. While observe that typically on moderately or very eccentric orbits highly inclined Galactic plane often retrograde, neither necessary nor sufficient conditions formation structure. That many objects be accreted leads us speculate this lack consistency may stem inhomogeneous dynamical history Way cluster system. Finally, note prominent envelopes detected ground-based (such as 1851 7089) now all known Gaia long – experimental confirmation presence an extended envelope indicative erosion.