Signatures of tidal disruption in the Milky Way globular cluster NGC 6981 (M72)

Abstract

We study the outer regions of the Milky Way globular cluster NGC6981 from publicly available $BV$ photometry and new Dark Energy Camera (DECam) observations, both reaching nearly 4 mag below the cluster main sequence (MS) turnoff. While the $BV$ data sets reveal the present of extra-tidal features around the cluster, the much larger field of view of DECam observations allowed us to identify some other tidal features, which extend from the cluster toward the opposite direction to the Milky Way center. These cluster structural features arise from stellar density maps built using MS stars, once the cluster color-magnitude diagram was cleaned from the contamination of field stars. We also performed $N$-body simulations in order to help us to understand the spatial distribution of the extra-tidal debris. The outcomes reveal the presenceof long trailing and leading tails mostly parallel to the direction of the cluster velocity vector. We found that the cluster has lost most of its mass by tidal disruption during its perigalactic passages, that lasted nearly 20 Myr each. Hence, a decrease in the density of escaping stars near the cluster is expected from our $N$-body simulations, which in turn means that stronger extra-tidal features could be found out by exploring much larger areas around NGC6891.

8 pages, 10 figures. Accepted for publication in Astronomy & Astrophysics

References in corpus (10)

• The Optical to Mid-Infrared Extinction Law Based on the APOGEE, Gaia DR2, Pan-STARRS1, SDSS, APASS, 2MASS and WISE Surveys
• Reverse engineering the Milky Way
• Homogeneous photometry VII. Globular clusters in the Gaia era
• The eye of Gaia on globular clusters structure: tidal tails
• A search for stellar tidal debris of defunct dwarf galaxies around globular clusters in the inner Galactic halo
• Tails and streams around the Galactic globular clusters NGC1851, NGC1904, NGC2298 and NGC2808
• On the tidal tails of Milky Way globular clusters
• Using Gaia DR2 to detect extratidal structures around the Galactic globular cluster NGC362
• G2C2-III: Structural parameters for Galactic globular clusters in SDSS passbands
• The disruption of the low-mass globular cluster E3

Cited by in corpus (2)

• Potential Black Hole Seeding of the Spiral Galaxy NGC 4424 via an Infalling Star Cluster
• The surroundings of the Milky Way globular cluster NGC 6809