Publication Date
8-1-2025
Document Type
Article
Publication Title
Monthly Notices of the Royal Astronomical Society
Volume
541
Issue
3
DOI
10.1093/mnras/staf1140
First Page
2761
Last Page
2772
Abstract
We present the analysis of the stellar populations and kinematics of the globular cluster (GC)-rich ultra-diffuse galaxy (UDG), PUDG-R21, using spectroscopic observations obtained with the Keck Cosmic Web Imager. The recessional velocity is measured to be 5536 ± 10 km s−1, confirming its association with the Perseus Cluster. The galaxy exhibits mild rotation of 15.6 ± 10 km s−1 and a stellar velocity dispersion of 19.4 ± 3.5 km s−1 within the galaxy effective radius. From this, we infer a dynamical mass of Mdyn = 9.3 ± 3.3 × 108 M☉. 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 ± 1.2 Gyr, with intermediate–low metallicity ([M/H] = −0.64 ± 0.12 dex) and elevated α abundances ([Mg/Fe] = 0.38 ± 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 (∼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 GCs, 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.
Funding Number
DP220101863
Funding Sponsor
Swinburne University of Technology
Keywords
galaxies: dwarf, galaxies: evolution, galaxies: kinematics and dynamics, galaxies: stellar content, techniques: spectroscopic
Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 License.
Department
Physics and Astronomy
Recommended Citation
Arsen Levitskiy, Duncan A. Forbes, Jonah S. Gannon, Anna Ferré-Mateu, Aaron J. Romanowsky, Jean P. Brodie, Warrick J. Couch, and Lydia Haacke. "A comprehensive look at PUDG-R21: stellar population and kinematics of a globular cluster-rich ultra-diffuse galaxy in the Perseus Cluster" Monthly Notices of the Royal Astronomical Society (2025): 2761-2772. https://doi.org/10.1093/mnras/staf1140
