FAST Discovery of A Gas-rich and Ultra-faint Dwarf Galaxy: KK153
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arXiv
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| Auteurs principaux: | , , , , , , |
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| Format: | Preprint |
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2025
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| _version_ | 1866915194084524032 |
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| author | Xu, Jin-Long Zhu, Ming Yu, Nai-Ping Zhang, Chuan-Peng Liu, Xiao-Lan Ai, Mei Jiang, Peng |
| author_facet | Xu, Jin-Long Zhu, Ming Yu, Nai-Ping Zhang, Chuan-Peng Liu, Xiao-Lan Ai, Mei Jiang, Peng |
| contents | Based on a high-sensitivity HI survey using the Five-hundred-meter Aperture Spherical radio Telescope (FAST), we identified an isolated HI cloud with a system velocity of ~127.0 km/s, which is associated with an optical galaxy KK153 in space. The HI 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 such distance, we derived a stellar mass of 4.1_{-2.6}^{+10.0}*10^{5} Msun and a neutral gas fraction of 0.63, implying that KK153 is a gas-rich ultra-faint dwarf (UFD) 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}*10^{7} Msun, 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 | Preprint |
| id |
arxiv_https___arxiv_org_abs_2503_08999 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | FAST Discovery of A Gas-rich and Ultra-faint Dwarf Galaxy: KK153 Xu, Jin-Long Zhu, Ming Yu, Nai-Ping Zhang, Chuan-Peng Liu, Xiao-Lan Ai, Mei Jiang, Peng Astrophysics of Galaxies Cosmology and Nongalactic Astrophysics Based on a high-sensitivity HI survey using the Five-hundred-meter Aperture Spherical radio Telescope (FAST), we identified an isolated HI cloud with a system velocity of ~127.0 km/s, which is associated with an optical galaxy KK153 in space. The HI 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 such distance, we derived a stellar mass of 4.1_{-2.6}^{+10.0}*10^{5} Msun and a neutral gas fraction of 0.63, implying that KK153 is a gas-rich ultra-faint dwarf (UFD) 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}*10^{7} Msun, 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. |
| title | FAST Discovery of A Gas-rich and Ultra-faint Dwarf Galaxy: KK153 |
| topic | Astrophysics of Galaxies Cosmology and Nongalactic Astrophysics |
| url | https://arxiv.org/abs/2503.08999 |