A Comprehensive Look at PUDG-R21: Stellar Population and Kinematics of a Globular Cluster-Rich Ultra-Diffuse Galaxy in the Perseus Cluster
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| Format: | Preprint |
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2025
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| _version_ | 1866908440502206464 |
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| author | Levitskiy, Arsen Forbes, Duncan A. Gannon, Jonah S. Ferré-Mateu, Anna Romanowsky, Aaron J. Brodie, Jean P. Couch, Warrick J. Haacke, Lydia |
| author_facet | Levitskiy, Arsen Forbes, Duncan A. Gannon, Jonah S. Ferré-Mateu, Anna Romanowsky, Aaron J. Brodie, Jean P. Couch, Warrick J. Haacke, Lydia |
| contents | We present the analysis of the stellar populations and kinematics of the globular cluster (GC) rich ultra-diffuse galaxy, PUDG-R21, using spectroscopic observations obtained with the Keck Cosmic Web Imager (KCWI). The recessional velocity is measured to be 5536$\pm$10 km s$^{\mathrm{-1}}$, confirming its association with the Perseus cluster. The galaxy exhibits mild rotation of 15.6$\pm$10 km s$^{\mathrm{-1}}$ and a stellar velocity dispersion of 19.4$\pm$3.5 km s$^{\mathrm{-1}}$ within the galaxy effective radius. From this, we infer a dynamical mass of M$_{\mathrm{dyn}}=9.3\pm3.3\times10^{8}$ M$_{\odot}$. Based on a halo mass derived from PUDG-R21 GC counts, we find our dynamical mass is consistent with a cored dark matter profile. The integrated stellar population analysis reveals a predominantly old stellar population of 10.4$\pm$1.2 Gyr, with intermediate-low metallicity ([M/H]=-0.64$\pm$0.12 dex) and elevated alpha abundances ([Mg/Fe]=0.38$\pm$0.25 dex). The inferred star formation history suggests rapid stellar assembly, likely truncating prior to or during the galaxy's infall into the cluster at an early epoch ($\sim$10 Gyr ago). The analysis of stellar population gradients (age and metallicity) indicates a flat profile out to one effective radius. Here, we consider the involvement of two star formation events, initially forming a large population of metal-poor globular clusters, and then the latter contributing to the more metal-enriched diffuse stellar body. The evidence of subsequent star formation suggests this galaxy is more like an extension of the classical dwarf population than the much discussed failed galaxy UDGs. |
| format | Preprint |
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arxiv_https___arxiv_org_abs_2507_05679 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | A Comprehensive Look at PUDG-R21: Stellar Population and Kinematics of a Globular Cluster-Rich Ultra-Diffuse Galaxy in the Perseus Cluster Levitskiy, Arsen Forbes, Duncan A. Gannon, Jonah S. Ferré-Mateu, Anna Romanowsky, Aaron J. Brodie, Jean P. Couch, Warrick J. Haacke, Lydia Astrophysics of Galaxies We present the analysis of the stellar populations and kinematics of the globular cluster (GC) rich ultra-diffuse galaxy, PUDG-R21, using spectroscopic observations obtained with the Keck Cosmic Web Imager (KCWI). The recessional velocity is measured to be 5536$\pm$10 km s$^{\mathrm{-1}}$, confirming its association with the Perseus cluster. The galaxy exhibits mild rotation of 15.6$\pm$10 km s$^{\mathrm{-1}}$ and a stellar velocity dispersion of 19.4$\pm$3.5 km s$^{\mathrm{-1}}$ within the galaxy effective radius. From this, we infer a dynamical mass of M$_{\mathrm{dyn}}=9.3\pm3.3\times10^{8}$ M$_{\odot}$. Based on a halo mass derived from PUDG-R21 GC counts, we find our dynamical mass is consistent with a cored dark matter profile. The integrated stellar population analysis reveals a predominantly old stellar population of 10.4$\pm$1.2 Gyr, with intermediate-low metallicity ([M/H]=-0.64$\pm$0.12 dex) and elevated alpha abundances ([Mg/Fe]=0.38$\pm$0.25 dex). The inferred star formation history suggests rapid stellar assembly, likely truncating prior to or during the galaxy's infall into the cluster at an early epoch ($\sim$10 Gyr ago). The analysis of stellar population gradients (age and metallicity) indicates a flat profile out to one effective radius. Here, we consider the involvement of two star formation events, initially forming a large population of metal-poor globular clusters, and then the latter contributing to the more metal-enriched diffuse stellar body. The evidence of subsequent star formation suggests this galaxy is more like an extension of the classical dwarf population than the much discussed failed galaxy UDGs. |
| title | A Comprehensive Look at PUDG-R21: Stellar Population and Kinematics of a Globular Cluster-Rich Ultra-Diffuse Galaxy in the Perseus Cluster |
| topic | Astrophysics of Galaxies |
| url | https://arxiv.org/abs/2507.05679 |