2015/09/15 by Zachary G. Jennings, Aaron J. Romanowsky, Jean P. Brodie +6 · 28 citations
Physics and Astronomy · #Astronomy and Astrophysical Research #Astrophysics and Star Formation Studies #Dwarf galaxy #Galaxy #Globular cluster #Luminosity #Milky Way #Population #Spiral galaxy #Star cluster #Stellar population #Stellar, planetary, and galactic studies #Surface brightness #astro-ph.GA
paper · pdf · doi:10.1088/2041-8205/812/1/l10
published in The Astrophysical Journal Letters 812(1), L10 (IOP Publishing) · 6 Pages, 3 Figures, Accepted to ApJ Letters
arxiv created 2015/09/15 · openalex publication_date 2015/10/07 · arxiv updated 2015/10/14 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
Using Subaru/Suprime-Cam wide-field imaging and both Keck/ESI and LBT/MODS spectroscopy, we identify and characterize a compact star cluster, which we term NGC 3628-UCD1, embedded in a stellar stream around the spiral galaxy NGC 3628. The size and luminosity of UCD1 are similar to ω Cen, the most luminous Milky Way globular cluster, which has long been suspected to be the stripped remnant of an accreted dwarf galaxy. The object has a magnitude of i = 19.3 mag ( ). UCD1 is marginally resolved in our ground-based imaging, with a half-light radius of ∼10 pc. We measure an integrated brightness for the stellar stream of i = 13.1 mag, with ( g − i ) = 1.0. This would correspond an accreted dwarf galaxy with an approximate luminosity of . Spectral analysis reveals that UCD1 has an age of 6.6 Gyr, and We propose that UCD1 is an example of an ω Cen-like star cluster possibly forming from the nucleus of an infalling dwarf galaxy, demonstrating that at least some of the massive star cluster population may be created through tidal stripping.