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arXiv · 2306.06164

The Disturbed and Globular Cluster-Rich Ultra-diffuse Galaxy UGC 9050-Dw1

Catherine E. Fielder·Michael G. Jones·David J. Sand·Paul Bennet·Denija Crnojevic·Ananthan Karunakaran·Burcin Mutlu-Pakdil·Kristine Spekkens
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Abstract

We investigate the ultra-diffuse 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 $\mathrm{H}\mathrm{I}$ content. UGC 9050-Dw1, a neighbor to the low surface brightness spiral UGC 9050, exhibits a unique UV bright central ``clump'' with clearly associated $\mathrm{H}{\mathrm{I}}$ gas and an extended stellar tidal plume to the north. We identify $52^{+4}_{-6}$ GCs, implying a specific frequency $S_\mathrm{N} = 122_{-24}^{+30}$, one of the highest reported for a UDG of this luminosity. Additionally, $\sim 20\%$ 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 propose that UGC 9050-Dw1 formed via a rare dwarf merger event where induced, clumpy star formation led to its current observed properties.

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Catherine E. Fielder, Michael G. Jones, David J. Sand, Paul Bennet, Denija Crnojevic, Ananthan Karunakaran, Burcin Mutlu-Pakdil, Kristine Spekkens. 2023-06-09. The Disturbed and Globular Cluster-Rich Ultra-diffuse Galaxy UGC 9050-Dw1. https://doi.org/10.3847/2041-8213%2Facf0c3

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