The Disturbed and Globular-cluster-rich Ultradiffuse Galaxy UGC 9050-Dw1

September 2023 • 2023ApJ...954L..39F

Authors • Fielder, Catherine E. • Jones, Michael G. • Sand, David J. • Bennet, Paul • Crnojević, Denija • Karunakaran, Ananthan • Mutlu-Pakdil, Burçin • Spekkens, Kristine

Abstract • We investigate the ultradiffuse galaxy (UDG) UGC 9050-Dw1, which was selected because of its disturbed morphology as part of a larger sample of UDGs that display evidence for significant interactions. We use the Hubble Space Telescope's Advanced Camera for Surveys to identify globular clusters (GCs) associated with UGC 9050-Dw1, and the Jansky Very Large Array to measure its H I content. UGC 9050-Dw1, a neighbor to the low surface brightness spiral UGC 9050, exhibits a unique UV-bright central "clump" with clearly associated H I gas and an extended stellar tidal plume to the north. We identify 52 ± 12 GCs, implying a specific frequency of S _N = 122 ± 38, one of the highest reported for a UDG of this luminosity ( $\mathrm{log}{L}_{V}/{L}_{\odot }=7.5\pm 0.1$ ). Additionally, ~20% of the total light of the galaxy is contributed by GCs. Nearly uniform GC colors suggest they were formed during a single intense episode of star formation. We posit that UGC 9050-Dw1 represents the initial definitive observational example of UDG formation resulting from a dwarf merger event, where subsequent clumpy star formation has contributed to its present observed characteristics.

Links

• PREPRINT http://arxiv.org/abs/2306.06164
• NED https://ned.ipac.caltech.edu/uri/NED::InRefcode/2023ApJ...954L..39F
• ELECTR https://doi.org/10.3847/2041-8213/acf0c3
• SIMBAD https://simbad.u-strasbg.fr/simbad/sim-ref?querymethod=bib&simbo=on&submit=submit+bibcode&bibcode=2023ApJ...954L..39F
• PDF https://iopscience.iop.org/article/10.3847/2041-8213/acf0c3/pdf
• DATA https://archive.stsci.edu/mastbibref.php?bibcode=2023ApJ...954L..39F
• DATA https://hst.esac.esa.int/ehst/#/pages/search;bibcode=2023ApJ...954L..39F