2016/06/20 by P. B. Kuzma, G. S. Da Costa, Dougal Mackey +2 · 1 voice · 3 citations
Physics and Astronomy · #Astrophysics and Star Formation Studies #Galaxies: Formation, Evolution, Phenomena #Stellar, planetary, and galactic studies #astro-ph.GA
paper · pdf · doi:10.1093/mnras/stw1561
15 pages, 12 figures, accepted for publishing in MNRAS
arxiv created 2016/06/20 · openalex publication_date 2016/07/01 · arxiv updated 2016/08/03 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/01
We present the results of a wide-field imaging survey of the periphery of the Milky Way globular cluster NGC 7089 (M2). Data were obtained with MegaCam on the Magellan Clay Telescope, and the Dark Energy Camera on the Blanco Telescope. We find that M2 is embedded in a diffuse stellar envelope extending to a radial distance of at least ∼ 60′ (∼ 210 pc) -- five times the nominal tidal radius of the cluster. The envelope appears nearly circular in shape, has a radial density decline well described by a power law of index γ= -2.2 ± 0.2, and contains approximately 1.6% of the luminosity of the entire system. While the origin of the envelope cannot be robustly identified using the presently available data, the fact that M2 also hosts stellar populations exhibiting a broad dispersion in the abundances of both iron and a variety of neutron capture elements suggests that this object might plausibly constitute the stripped nucleus of a dwarf Galaxy that was long ago accreted and destroyed by the Milky Way.