Caught in the Act of Quenching? -- A Population of Post-Starburst Ultra-Diffuse Galaxies
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arXiv
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| Autori principali: | , , , , , |
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| Natura: | Preprint |
| Pubblicazione: |
2025
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| author | Ascencio, Loraine Sandoval Cooper, M. C. Zaritsky, Dennis Donnerstein, Richard Khim, Donghyeon J. Baxter, Devontae C. |
| author_facet | Ascencio, Loraine Sandoval Cooper, M. C. Zaritsky, Dennis Donnerstein, Richard Khim, Donghyeon J. Baxter, Devontae C. |
| contents | We report the discovery of post-starburst ultra-diffuse galaxies (UDGs), identified through spectroscopic analysis with KCWI at the Keck II Telescope. Our analysis is based on a sample of 44 candidate UDGs selected from the Systematically Measuring Ultra-Diffuse Galaxies (SMUDGes) program. Our measured spectroscopic redshifts reveal $\sim 85\%$ of the entire KCWI sample exhibit large physical sizes ($R_{e} \gtrsim 1~{\rm kpc}$) and low surface brightnesses ($24 \lesssim μ_{0,g} \lesssim 25$ mag arcsec$^{-2}$) which categorize them as UDGs. We find $20\%$ of the confirmed UDG population contain post-starburst (or K+A) features, characterized by minimal to no emission in H$β$ indicative of quenched star formation and a predominant presence of spectral A-type stars. In surveying the local environments of the post-starburst UDGs, we find that nearly half are isolated systems, which is unusual given that isolated UDGs are most commonly found to be star-forming. Two of these systems reside $2-3~R_{\rm vir}$ away from potential nearby massive hosts ($M_{\star} >10^{10}~\mathrm{M}_{\odot}$), indicating the absence of environmental influence. These post-starburst UDGs may represent systems experiencing star formation feedback such that a recent burst may lead to (at least temporary) quenching. Overall, our results highlight the potentially diverse quenching pathways of UDGs in the local Universe. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2502_00117 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Caught in the Act of Quenching? -- A Population of Post-Starburst Ultra-Diffuse Galaxies Ascencio, Loraine Sandoval Cooper, M. C. Zaritsky, Dennis Donnerstein, Richard Khim, Donghyeon J. Baxter, Devontae C. Astrophysics of Galaxies We report the discovery of post-starburst ultra-diffuse galaxies (UDGs), identified through spectroscopic analysis with KCWI at the Keck II Telescope. Our analysis is based on a sample of 44 candidate UDGs selected from the Systematically Measuring Ultra-Diffuse Galaxies (SMUDGes) program. Our measured spectroscopic redshifts reveal $\sim 85\%$ of the entire KCWI sample exhibit large physical sizes ($R_{e} \gtrsim 1~{\rm kpc}$) and low surface brightnesses ($24 \lesssim μ_{0,g} \lesssim 25$ mag arcsec$^{-2}$) which categorize them as UDGs. We find $20\%$ of the confirmed UDG population contain post-starburst (or K+A) features, characterized by minimal to no emission in H$β$ indicative of quenched star formation and a predominant presence of spectral A-type stars. In surveying the local environments of the post-starburst UDGs, we find that nearly half are isolated systems, which is unusual given that isolated UDGs are most commonly found to be star-forming. Two of these systems reside $2-3~R_{\rm vir}$ away from potential nearby massive hosts ($M_{\star} >10^{10}~\mathrm{M}_{\odot}$), indicating the absence of environmental influence. These post-starburst UDGs may represent systems experiencing star formation feedback such that a recent burst may lead to (at least temporary) quenching. Overall, our results highlight the potentially diverse quenching pathways of UDGs in the local Universe. |
| title | Caught in the Act of Quenching? -- A Population of Post-Starburst Ultra-Diffuse Galaxies |
| topic | Astrophysics of Galaxies |
| url | https://arxiv.org/abs/2502.00117 |