FAST Discovery of a Gas-rich and Ultrafaint Dwarf Galaxy: KK153
Based on a high-sensitivity H i survey using the Five-hundred-meter Aperture Spherical radio Telescope, we identified an isolated H i cloud with a system velocity of ∼127.0 km s ^−1 , which is associated with an optical galaxy KK153 in space. The H i gas of KK153 shows a typical disk-galaxy structu...
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| Format: | Article |
| Language: | English |
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IOP Publishing
2025-01-01
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| Series: | The Astrophysical Journal Letters |
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| Online Access: | https://doi.org/10.3847/2041-8213/adbe7e |
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| author | Jin-Long Xu Ming Zhu Nai-Ping Yu Chuan-Peng Zhang Xiao-Lan Liu Mei Ai Peng Jiang |
| author_facet | Jin-Long Xu Ming Zhu Nai-Ping Yu Chuan-Peng Zhang Xiao-Lan Liu Mei Ai Peng Jiang |
| author_sort | Jin-Long Xu |
| collection | DOAJ |
| description | Based on a high-sensitivity H i survey using the Five-hundred-meter Aperture Spherical radio Telescope, we identified an isolated H i cloud with a system velocity of ∼127.0 km s ^−1 , which is associated with an optical galaxy KK153 in space. The H i gas of KK153 shows a typical disk-galaxy structure. Using the baryonic Tully–Fisher relation, we obtained that the distance to KK153 is 2.0 ${}_{-0.8}^{+1.7}$ Mpc. Adopting this distance, we derived a stellar mass of 4.1 ${}_{-2.6}^{+10.0}\times 1{0}^{5}$ M _⊙ and a neutral gas fraction of 0.63, implying that KK153 is a gas-rich ultrafaint dwarf galaxy in the Local Group or its outskirts. KK153 shows a cool (∼200 K) and warm (∼7400 K) two-phase neutral medium. The g − r color distribution of KK153 suggests that new stars are mostly forming in its inner disk. The dynamical mass of KK153 is 6.9 ${}_{-3.0}^{+5.5}\times 1{0}^{7}$ M _⊙ , which is about 60 times larger than its baryonic matter. Detection of such a low-mass and gas-rich halo poses a challenge to the theory of cosmic reionization. |
| format | Article |
| id | doaj-art-7ea8b69de17444b98d606fe1a72061e1 |
| institution | DOAJ |
| issn | 2041-8205 |
| language | English |
| publishDate | 2025-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | The Astrophysical Journal Letters |
| spelling | doaj-art-7ea8b69de17444b98d606fe1a72061e12025-08-20T02:40:32ZengIOP PublishingThe Astrophysical Journal Letters2041-82052025-01-019822L3610.3847/2041-8213/adbe7eFAST Discovery of a Gas-rich and Ultrafaint Dwarf Galaxy: KK153Jin-Long Xu0https://orcid.org/0000-0002-7384-797XMing Zhu1https://orcid.org/0000-0001-6083-956XNai-Ping Yu2Chuan-Peng Zhang3https://orcid.org/0000-0002-4428-3183Xiao-Lan Liu4https://orcid.org/0000-0002-1768-9591Mei Ai5Peng Jiang6https://orcid.org/0000-0002-5387-7952National Astronomical Observatories, Chinese Academy of Sciences , Beijing 100101, People’s Republic of China ; xujl@bao.ac.cn; Guizhou Radio Astronomical Observatory, Guizhou University , Guiyang 550000, People’s Republic of ChinaNational Astronomical Observatories, Chinese Academy of Sciences , Beijing 100101, People’s Republic of China ; xujl@bao.ac.cn; Guizhou Radio Astronomical Observatory, Guizhou University , Guiyang 550000, People’s Republic of ChinaNational Astronomical Observatories, Chinese Academy of Sciences , Beijing 100101, People’s Republic of China ; xujl@bao.ac.cn; Guizhou Radio Astronomical Observatory, Guizhou University , Guiyang 550000, People’s Republic of ChinaNational Astronomical Observatories, Chinese Academy of Sciences , Beijing 100101, People’s Republic of China ; xujl@bao.ac.cn; Guizhou Radio Astronomical Observatory, Guizhou University , Guiyang 550000, People’s Republic of ChinaNational Astronomical Observatories, Chinese Academy of Sciences , Beijing 100101, People’s Republic of China ; xujl@bao.ac.cn; Guizhou Radio Astronomical Observatory, Guizhou University , Guiyang 550000, People’s Republic of ChinaNational Astronomical Observatories, Chinese Academy of Sciences , Beijing 100101, People’s Republic of China ; xujl@bao.ac.cn; Guizhou Radio Astronomical Observatory, Guizhou University , Guiyang 550000, People’s Republic of ChinaNational Astronomical Observatories, Chinese Academy of Sciences , Beijing 100101, People’s Republic of China ; xujl@bao.ac.cn; Guizhou Radio Astronomical Observatory, Guizhou University , Guiyang 550000, People’s Republic of ChinaBased on a high-sensitivity H i survey using the Five-hundred-meter Aperture Spherical radio Telescope, we identified an isolated H i cloud with a system velocity of ∼127.0 km s ^−1 , which is associated with an optical galaxy KK153 in space. The H i gas of KK153 shows a typical disk-galaxy structure. Using the baryonic Tully–Fisher relation, we obtained that the distance to KK153 is 2.0 ${}_{-0.8}^{+1.7}$ Mpc. Adopting this distance, we derived a stellar mass of 4.1 ${}_{-2.6}^{+10.0}\times 1{0}^{5}$ M _⊙ and a neutral gas fraction of 0.63, implying that KK153 is a gas-rich ultrafaint dwarf galaxy in the Local Group or its outskirts. KK153 shows a cool (∼200 K) and warm (∼7400 K) two-phase neutral medium. The g − r color distribution of KK153 suggests that new stars are mostly forming in its inner disk. The dynamical mass of KK153 is 6.9 ${}_{-3.0}^{+5.5}\times 1{0}^{7}$ M _⊙ , which is about 60 times larger than its baryonic matter. Detection of such a low-mass and gas-rich halo poses a challenge to the theory of cosmic reionization.https://doi.org/10.3847/2041-8213/adbe7eDwarf galaxiesGalaxy formationGalaxy evolution |
| spellingShingle | Jin-Long Xu Ming Zhu Nai-Ping Yu Chuan-Peng Zhang Xiao-Lan Liu Mei Ai Peng Jiang FAST Discovery of a Gas-rich and Ultrafaint Dwarf Galaxy: KK153 The Astrophysical Journal Letters Dwarf galaxies Galaxy formation Galaxy evolution |
| title | FAST Discovery of a Gas-rich and Ultrafaint Dwarf Galaxy: KK153 |
| title_full | FAST Discovery of a Gas-rich and Ultrafaint Dwarf Galaxy: KK153 |
| title_fullStr | FAST Discovery of a Gas-rich and Ultrafaint Dwarf Galaxy: KK153 |
| title_full_unstemmed | FAST Discovery of a Gas-rich and Ultrafaint Dwarf Galaxy: KK153 |
| title_short | FAST Discovery of a Gas-rich and Ultrafaint Dwarf Galaxy: KK153 |
| title_sort | fast discovery of a gas rich and ultrafaint dwarf galaxy kk153 |
| topic | Dwarf galaxies Galaxy formation Galaxy evolution |
| url | https://doi.org/10.3847/2041-8213/adbe7e |
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