Spectroscopic Confirmation of the Sixth Globular Cluster in the Fornax
Draft version May 4, 2021 Typeset using LATEX twocolumn style in AASTeX63 Spectroscopic Confirmation of the Sixth Globular Cluster in the Fornax Dwarf Spheroidal Galaxy∗ Andrew B. Pace ,1 Matthew G. Walker ,1 Sergey E. Koposov ,2, 3, 1 Nelson Caldwell ,4 Mario Mateo,5 Edward W. Olszewski ,6 John I. Bailey, III ,7 and Mei-Yu Wang 1 1McWilliams Center for Cosmology, Carnegie Mellon University, 5000 Forbes Ave, Pittsburgh, PA 15213, USA 2Institute for Astronomy, University of Edinburgh, Royal Observatory, Blackford Hill, Edinburgh EH9 3HJ, UK 3Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA, UK 4Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, MS-15, Cambridge, MA 02138, USA 5Department of Astronomy, University of Michigan, Ann Arbor, MI 48109, USA 6Steward Observatory, The University of Arizona, 933 N. Cherry Avenue, Tucson, AZ 85721, USA 7Department of Physics, UCSB, Santa Barbara, CA 93016, USA (Received; Revised; Accepted) Submitted to ApJ ABSTRACT The Fornax dwarf spheroidal galaxy has an anomalous number of globular clusters, five, for its stellar mass. There is a longstanding debate about a potential sixth globular cluster (Fornax 6) that has recently been `rediscovered' in DECam imaging. We present new Magellan/M2FS spectroscopy of the Fornax 6 cluster and Fornax dSph. Combined with literature data we identify ∼ 15 − 17 members of the Fornax 6 cluster that this overdensity is indeed a star cluster and associated with the Fornax dSph. The cluster is significantly more metal-rich (mean metallicity of [Fe=H] = −0:71 ± 0:05) than the other five Fornax globular clusters (−2:5 < [F e=H] < −1:4) and more metal-rich than the +2:0 −1 bulk of Fornax.
[Show full text]