Deep Neutral Hydrogen Observations of the Early-type Galaxy NGC 2768: Collided by a Newly Discovered Satellite Galaxy?
We present the results of a deep neutral hydrogen (H i ) observation of the early-type galaxy NGC 2768 using the Five-hundred-meter Aperture Spherical radio Telescope (FAST). Leveraging the high sensitivity of FAST, we discover an extended gas envelope around NGC 2768. The total H i mass is measured...
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2025-01-01
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| Online Access: | https://doi.org/10.3847/1538-4357/ade30b |
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| author | Nai-Ping Yu Ming Zhu Jin-Long Xu Chuan-Peng Zhang Xiao-Lan Liu Peng Jiang |
| author_facet | Nai-Ping Yu Ming Zhu Jin-Long Xu Chuan-Peng Zhang Xiao-Lan Liu Peng Jiang |
| author_sort | Nai-Ping Yu |
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| description | We present the results of a deep neutral hydrogen (H i ) observation of the early-type galaxy NGC 2768 using the Five-hundred-meter Aperture Spherical radio Telescope (FAST). Leveraging the high sensitivity of FAST, we discover an extended gas envelope around NGC 2768. The total H i mass is measured to be 8.1 × 10 ^8 M _⊙ , representing a magnitude increase compared to previous Westerbork Synthesis Radio Telescope (WSRT) studies. A position-velocity (PV) diagram indicates the envelope mainly involves two components: an H i disk of NGC 2768 and a newly discovered satellite galaxy without detectable counterparts in currently deep optical surveys. The center of the gas disk is misaligned with the optical disk of NGC 2768, with more gas redshifted, indicating it has been disturbed. Our study indicates NGC 2768 is currently undergoing a transition from a spiral galaxy to an S0. Previous deep WSRT observations reveal two dense clumps (named “Clumps A” and “Clump B” throughout this paper) in the center of the envelope. We find Clump A corresponds to the densest part of the disk, while Clump B might be a newly discovered satellite galaxy that probably collided with NGC 2768 about 0.38 Gyr ago. We also find tidal interactions between Clump B and PGC 2599651, NGC 2768, and UGC 4808. Based on these new findings, we finally analyze the hierarchical accretion history of NGC 2768. |
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| institution | Kabale University |
| issn | 1538-4357 |
| language | English |
| publishDate | 2025-01-01 |
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| spelling | doaj-art-2627813fa7a74624945e7ffa49df99932025-08-20T03:29:14ZengIOP PublishingThe Astrophysical Journal1538-43572025-01-01987210910.3847/1538-4357/ade30bDeep Neutral Hydrogen Observations of the Early-type Galaxy NGC 2768: Collided by a Newly Discovered Satellite Galaxy?Nai-Ping Yu0https://orcid.org/0000-0003-1241-7439Ming Zhu1https://orcid.org/0000-0001-6083-956XJin-Long Xu2https://orcid.org/0000-0002-7384-797XChuan-Peng Zhang3https://orcid.org/0000-0002-4428-3183Xiao-Lan Liu4https://orcid.org/0000-0002-1768-9591Peng Jiang5https://orcid.org/0000-0002-5387-7952Guizhou Radio Astronomical Observatory, Guizhou University , Guiyang 550000, People’s Republic of China ; npyu@bao.ac.cn, mz@nao.cas.cn, xujl@bao.ac.cn; National Astronomical Observatories, Chinese Academy of Sciences , Beijing 100101, People’s Republic of China; CAS Key Laboratory of FAST, National Astronomical Observatories, Chinese Academy of Sciences , Beijing 100101, People’s Republic of ChinaGuizhou Radio Astronomical Observatory, Guizhou University , Guiyang 550000, People’s Republic of China ; npyu@bao.ac.cn, mz@nao.cas.cn, xujl@bao.ac.cn; National Astronomical Observatories, Chinese Academy of Sciences , Beijing 100101, People’s Republic of China; CAS Key Laboratory of FAST, National Astronomical Observatories, Chinese Academy of Sciences , Beijing 100101, People’s Republic of ChinaGuizhou Radio Astronomical Observatory, Guizhou University , Guiyang 550000, People’s Republic of China ; npyu@bao.ac.cn, mz@nao.cas.cn, xujl@bao.ac.cn; National Astronomical Observatories, Chinese Academy of Sciences , Beijing 100101, People’s Republic of China; CAS Key Laboratory of FAST, National Astronomical Observatories, Chinese Academy of Sciences , Beijing 100101, People’s Republic of ChinaGuizhou Radio Astronomical Observatory, Guizhou University , Guiyang 550000, People’s Republic of China ; npyu@bao.ac.cn, mz@nao.cas.cn, xujl@bao.ac.cn; National Astronomical Observatories, Chinese Academy of Sciences , Beijing 100101, People’s Republic of China; CAS Key Laboratory of FAST, National Astronomical Observatories, Chinese Academy of Sciences , Beijing 100101, People’s Republic of ChinaGuizhou Radio Astronomical Observatory, Guizhou University , Guiyang 550000, People’s Republic of China ; npyu@bao.ac.cn, mz@nao.cas.cn, xujl@bao.ac.cn; National Astronomical Observatories, Chinese Academy of Sciences , Beijing 100101, People’s Republic of China; CAS Key Laboratory of FAST, National Astronomical Observatories, Chinese Academy of Sciences , Beijing 100101, People’s Republic of ChinaGuizhou Radio Astronomical Observatory, Guizhou University , Guiyang 550000, People’s Republic of China ; npyu@bao.ac.cn, mz@nao.cas.cn, xujl@bao.ac.cn; National Astronomical Observatories, Chinese Academy of Sciences , Beijing 100101, People’s Republic of China; CAS Key Laboratory of FAST, National Astronomical Observatories, Chinese Academy of Sciences , Beijing 100101, People’s Republic of ChinaWe present the results of a deep neutral hydrogen (H i ) observation of the early-type galaxy NGC 2768 using the Five-hundred-meter Aperture Spherical radio Telescope (FAST). Leveraging the high sensitivity of FAST, we discover an extended gas envelope around NGC 2768. The total H i mass is measured to be 8.1 × 10 ^8 M _⊙ , representing a magnitude increase compared to previous Westerbork Synthesis Radio Telescope (WSRT) studies. A position-velocity (PV) diagram indicates the envelope mainly involves two components: an H i disk of NGC 2768 and a newly discovered satellite galaxy without detectable counterparts in currently deep optical surveys. The center of the gas disk is misaligned with the optical disk of NGC 2768, with more gas redshifted, indicating it has been disturbed. Our study indicates NGC 2768 is currently undergoing a transition from a spiral galaxy to an S0. Previous deep WSRT observations reveal two dense clumps (named “Clumps A” and “Clump B” throughout this paper) in the center of the envelope. We find Clump A corresponds to the densest part of the disk, while Clump B might be a newly discovered satellite galaxy that probably collided with NGC 2768 about 0.38 Gyr ago. We also find tidal interactions between Clump B and PGC 2599651, NGC 2768, and UGC 4808. Based on these new findings, we finally analyze the hierarchical accretion history of NGC 2768.https://doi.org/10.3847/1538-4357/ade30bGalaxy interactionsGalaxy structure |
| spellingShingle | Nai-Ping Yu Ming Zhu Jin-Long Xu Chuan-Peng Zhang Xiao-Lan Liu Peng Jiang Deep Neutral Hydrogen Observations of the Early-type Galaxy NGC 2768: Collided by a Newly Discovered Satellite Galaxy? The Astrophysical Journal Galaxy interactions Galaxy structure |
| title | Deep Neutral Hydrogen Observations of the Early-type Galaxy NGC 2768: Collided by a Newly Discovered Satellite Galaxy? |
| title_full | Deep Neutral Hydrogen Observations of the Early-type Galaxy NGC 2768: Collided by a Newly Discovered Satellite Galaxy? |
| title_fullStr | Deep Neutral Hydrogen Observations of the Early-type Galaxy NGC 2768: Collided by a Newly Discovered Satellite Galaxy? |
| title_full_unstemmed | Deep Neutral Hydrogen Observations of the Early-type Galaxy NGC 2768: Collided by a Newly Discovered Satellite Galaxy? |
| title_short | Deep Neutral Hydrogen Observations of the Early-type Galaxy NGC 2768: Collided by a Newly Discovered Satellite Galaxy? |
| title_sort | deep neutral hydrogen observations of the early type galaxy ngc 2768 collided by a newly discovered satellite galaxy |
| topic | Galaxy interactions Galaxy structure |
| url | https://doi.org/10.3847/1538-4357/ade30b |
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