Gas Transfer between the Inner 3 kpc Disk and the Galactic Central Molecular Zone
We uncovered a more tilted molecular gas structure with highly negative velocities located near the dust lane. Our observations show that the approaching gas flows from the overshoot process are captured by the gravitational potential of the bar and then flow toward the Galactic central molecular zo...
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IOP Publishing
2025-01-01
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| Series: | The Astrophysical Journal |
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| Online Access: | https://doi.org/10.3847/1538-4357/adc38e |
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| author | Yang Su Shiyu Zhang Yan Sun Ji Yang Fujun Du Min Fang Qing-Zeng Yan Shaobo Zhang Zhiwei Chen Xuepeng Chen Xin Zhou Lixia Yuan Yuehui Ma |
| author_facet | Yang Su Shiyu Zhang Yan Sun Ji Yang Fujun Du Min Fang Qing-Zeng Yan Shaobo Zhang Zhiwei Chen Xuepeng Chen Xin Zhou Lixia Yuan Yuehui Ma |
| author_sort | Yang Su |
| collection | DOAJ |
| description | We uncovered a more tilted molecular gas structure with highly negative velocities located near the dust lane. Our observations show that the approaching gas flows from the overshoot process are captured by the gravitational potential of the bar and then flow toward the Galactic central molecular zone (CMZ) through the bar channel. The recycled gas from the overshoot effect, in conjunction with freshly accreted gas from the inner 3 kpc disk, accumulates significantly near the ${R}_{{\rm{GC}}}\sim \frac{1}{2}{R}_{{\rm{bar}}}$ and ${R}_{{\rm{GC}}}\sim \frac{2}{3}{R}_{{\rm{bar}}}$ regions by adopting a bar length of ∼3.2–3.4 kpc. Importantly, within these regions, there are frequent collisions and substantial angular momentum exchanges between gas flows with different trajectories. In this scenario, the dissipation processes arising from interactions between colliding flows, together with the varying torques induced by the nonaxisymmetric bar, effectively transfer the angular momentum of viscous gas outward, thereby driving the molecular gas to settle into the CMZ within about three orbital periods. A long-term gas inflow with an average rate of ≳1.1 M _⊙ yr ^−1 , coupled with intense transient accretion events that exceed the average rate by several times due to the overshoot effect, significantly regulates the gas distribution, physical properties, and dynamical evolution of the CMZ. These new findings provide robust observational evidence for elucidating the intricate dynamics of molecular gas flows toward the CMZ. Our observations suggest that gas dynamics have a significant impact on the secular evolution of both the Milky Way and the extragalactic gas-rich galaxies. |
| format | Article |
| id | doaj-art-a07c1b9b47f64184aaa2f78ee11e54c4 |
| institution | Kabale University |
| issn | 1538-4357 |
| language | English |
| publishDate | 2025-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | The Astrophysical Journal |
| spelling | doaj-art-a07c1b9b47f64184aaa2f78ee11e54c42025-08-20T03:52:07ZengIOP PublishingThe Astrophysical Journal1538-43572025-01-01984210910.3847/1538-4357/adc38eGas Transfer between the Inner 3 kpc Disk and the Galactic Central Molecular ZoneYang Su0https://orcid.org/0000-0002-0197-470XShiyu Zhang1https://orcid.org/0009-0002-2379-4395Yan Sun2https://orcid.org/0000-0002-3904-1622Ji Yang3https://orcid.org/0000-0001-7768-7320Fujun Du4https://orcid.org/0000-0002-7489-0179Min Fang5https://orcid.org/0000-0001-8060-1321Qing-Zeng Yan6https://orcid.org/0000-0003-4586-7751Shaobo Zhang7https://orcid.org/0000-0003-2549-7247Zhiwei Chen8https://orcid.org/0000-0003-0849-0692Xuepeng Chen9https://orcid.org/0000-0003-3151-8964Xin Zhou10https://orcid.org/0000-0003-2418-3350Lixia Yuan11https://orcid.org/0000-0003-0804-9055Yuehui Ma12https://orcid.org/0000-0002-8051-5228Purple Mountain Observatory , Chinese Academy of Sciences, 10 Yuanhua Road, Nanjing 210023, People’s Republic of China ; yangsu@pmo.ac.cn; School of Astronomy and Space Science, University of Science and Technology of China , 96 Jinzhai Road, Hefei 230026, People’s Republic of ChinaPurple Mountain Observatory , Chinese Academy of Sciences, 10 Yuanhua Road, Nanjing 210023, People’s Republic of China ; yangsu@pmo.ac.cn; School of Astronomy and Space Science, University of Science and Technology of China , 96 Jinzhai Road, Hefei 230026, People’s Republic of ChinaPurple Mountain Observatory , Chinese Academy of Sciences, 10 Yuanhua Road, Nanjing 210023, People’s Republic of China ; yangsu@pmo.ac.cn; School of Astronomy and Space Science, University of Science and Technology of China , 96 Jinzhai Road, Hefei 230026, People’s Republic of ChinaPurple Mountain Observatory , Chinese Academy of Sciences, 10 Yuanhua Road, Nanjing 210023, People’s Republic of China ; yangsu@pmo.ac.cn; School of Astronomy and Space Science, University of Science and Technology of China , 96 Jinzhai Road, Hefei 230026, People’s Republic of ChinaPurple Mountain Observatory , Chinese Academy of Sciences, 10 Yuanhua Road, Nanjing 210023, People’s Republic of China ; yangsu@pmo.ac.cn; School of Astronomy and Space Science, University of Science and Technology of China , 96 Jinzhai Road, Hefei 230026, People’s Republic of ChinaPurple Mountain Observatory , Chinese Academy of Sciences, 10 Yuanhua Road, Nanjing 210023, People’s Republic of China ; yangsu@pmo.ac.cn; School of Astronomy and Space Science, University of Science and Technology of China , 96 Jinzhai Road, Hefei 230026, People’s Republic of ChinaPurple Mountain Observatory , Chinese Academy of Sciences, 10 Yuanhua Road, Nanjing 210023, People’s Republic of China ; yangsu@pmo.ac.cnPurple Mountain Observatory , Chinese Academy of Sciences, 10 Yuanhua Road, Nanjing 210023, People’s Republic of China ; yangsu@pmo.ac.cnPurple Mountain Observatory , Chinese Academy of Sciences, 10 Yuanhua Road, Nanjing 210023, People’s Republic of China ; yangsu@pmo.ac.cnPurple Mountain Observatory , Chinese Academy of Sciences, 10 Yuanhua Road, Nanjing 210023, People’s Republic of China ; yangsu@pmo.ac.cn; School of Astronomy and Space Science, University of Science and Technology of China , 96 Jinzhai Road, Hefei 230026, People’s Republic of ChinaPurple Mountain Observatory , Chinese Academy of Sciences, 10 Yuanhua Road, Nanjing 210023, People’s Republic of China ; yangsu@pmo.ac.cnPurple Mountain Observatory , Chinese Academy of Sciences, 10 Yuanhua Road, Nanjing 210023, People’s Republic of China ; yangsu@pmo.ac.cnPurple Mountain Observatory , Chinese Academy of Sciences, 10 Yuanhua Road, Nanjing 210023, People’s Republic of China ; yangsu@pmo.ac.cnWe uncovered a more tilted molecular gas structure with highly negative velocities located near the dust lane. Our observations show that the approaching gas flows from the overshoot process are captured by the gravitational potential of the bar and then flow toward the Galactic central molecular zone (CMZ) through the bar channel. The recycled gas from the overshoot effect, in conjunction with freshly accreted gas from the inner 3 kpc disk, accumulates significantly near the ${R}_{{\rm{GC}}}\sim \frac{1}{2}{R}_{{\rm{bar}}}$ and ${R}_{{\rm{GC}}}\sim \frac{2}{3}{R}_{{\rm{bar}}}$ regions by adopting a bar length of ∼3.2–3.4 kpc. Importantly, within these regions, there are frequent collisions and substantial angular momentum exchanges between gas flows with different trajectories. In this scenario, the dissipation processes arising from interactions between colliding flows, together with the varying torques induced by the nonaxisymmetric bar, effectively transfer the angular momentum of viscous gas outward, thereby driving the molecular gas to settle into the CMZ within about three orbital periods. A long-term gas inflow with an average rate of ≳1.1 M _⊙ yr ^−1 , coupled with intense transient accretion events that exceed the average rate by several times due to the overshoot effect, significantly regulates the gas distribution, physical properties, and dynamical evolution of the CMZ. These new findings provide robust observational evidence for elucidating the intricate dynamics of molecular gas flows toward the CMZ. Our observations suggest that gas dynamics have a significant impact on the secular evolution of both the Milky Way and the extragalactic gas-rich galaxies.https://doi.org/10.3847/1538-4357/adc38eInterstellar mediumMolecular cloudsGalaxy kinematicsMilky Way GalaxyGalaxy structureMilky Way dynamics |
| spellingShingle | Yang Su Shiyu Zhang Yan Sun Ji Yang Fujun Du Min Fang Qing-Zeng Yan Shaobo Zhang Zhiwei Chen Xuepeng Chen Xin Zhou Lixia Yuan Yuehui Ma Gas Transfer between the Inner 3 kpc Disk and the Galactic Central Molecular Zone The Astrophysical Journal Interstellar medium Molecular clouds Galaxy kinematics Milky Way Galaxy Galaxy structure Milky Way dynamics |
| title | Gas Transfer between the Inner 3 kpc Disk and the Galactic Central Molecular Zone |
| title_full | Gas Transfer between the Inner 3 kpc Disk and the Galactic Central Molecular Zone |
| title_fullStr | Gas Transfer between the Inner 3 kpc Disk and the Galactic Central Molecular Zone |
| title_full_unstemmed | Gas Transfer between the Inner 3 kpc Disk and the Galactic Central Molecular Zone |
| title_short | Gas Transfer between the Inner 3 kpc Disk and the Galactic Central Molecular Zone |
| title_sort | gas transfer between the inner 3 kpc disk and the galactic central molecular zone |
| topic | Interstellar medium Molecular clouds Galaxy kinematics Milky Way Galaxy Galaxy structure Milky Way dynamics |
| url | https://doi.org/10.3847/1538-4357/adc38e |
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