Spectroscopic confirmation of the sixth globular cluster in the Fornax dwarf spheroidal galaxy. (2021)
Keywords :
Globular star clusters; Dwarf spheroidal galaxies
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, showing 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<[Fe/H]{<}-1.4) and more metal-rich than the bulk of Fornax. We measure a velocity dispersion of 5.6_-1.6_^+2.0^kms^-1^
...(more)
We present results from new spectroscopic observations of Fornax stars
that we obtained using the Michigan/Magellan Fiber System (M2FS) at
the 6.5m Magellan/Clay Telescope at Las Campanas Observatory, Chile.
We used a configuration that covered the approximate range 5130-5190{AA}
at resolution R~24000. Between the years 2018 and 2020, we observed 8
Fornax fields with M2FS.
We include additional Magellan/MIKE Fiber System (MMFS) spectroscopic
data from Walker+ 2009, J/AJ/137/3100 which increases the number of
Fornax members by ~2400 stars.
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