The Rotating Bulge and Halo in the Milky Way: Evidence of Angular Momentum Transferred from the Decelerating Bar
Recent observations indicate that both the Milky Way bulge and inner halo exhibit angular momentum, although the origin and evolution of this prograde signature remain ambiguous. One plausible scenario involves secular evolution induced by the central bar and spiral arms. In this study, we identifie...
Saved in:
| Main Authors: | , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
IOP Publishing
2025-01-01
|
| Series: | The Astrophysical Journal |
| Subjects: | |
| Online Access: | https://doi.org/10.3847/1538-4357/ade430 |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| _version_ | 1849317682500861952 |
|---|---|
| author | Zhuohan Li Chengdong Li Gang Zhao Ruizhi Zhang Xiang-Xiang Xue |
| author_facet | Zhuohan Li Chengdong Li Gang Zhao Ruizhi Zhang Xiang-Xiang Xue |
| author_sort | Zhuohan Li |
| collection | DOAJ |
| description | Recent observations indicate that both the Milky Way bulge and inner halo exhibit angular momentum, although the origin and evolution of this prograde signature remain ambiguous. One plausible scenario involves secular evolution induced by the central bar and spiral arms. In this study, we identified a component consisting of 1,175,737 stars with net rotation through the application of a neural network (NN) method. To investigate the composition of this rotating sample and the origin of its rotation, we conducted a test particle simulation incorporating an equilibrium axisymmetric background potential together with a central decelerating bar. The test particles were generated using a distribution function model derived from observational constraints. Our results indicate that the decelerating bar transfers angular momentum to the pseudo-stars, and the rotational profile from our simulation shows strong agreement with observational data. These findings suggest that the rotating sample identified by our NN model is predominantly comprised of bulge, halo, and thick disk stars, and that the central decelerating bar is pivotal in shaping the inner Galaxy’s kinematics through angular momentum transfer. |
| format | Article |
| id | doaj-art-bf42d23b969f44eeb6038b504a714ad1 |
| 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-bf42d23b969f44eeb6038b504a714ad12025-08-20T03:51:08ZengIOP PublishingThe Astrophysical Journal1538-43572025-01-01988112410.3847/1538-4357/ade430The Rotating Bulge and Halo in the Milky Way: Evidence of Angular Momentum Transferred from the Decelerating BarZhuohan Li0https://orcid.org/0000-0002-1126-9289Chengdong Li1https://orcid.org/0000-0001-9949-0625Gang Zhao2https://orcid.org/0000-0002-8980-945XRuizhi Zhang3https://orcid.org/0009-0008-1319-1084Xiang-Xiang Xue4https://orcid.org/0000-0002-0642-5689National Astronomical Observatories , Chinese Academy of Sciences, Beijing 100101, People’s Republic of China ; gzhao@nao.cas.cn; School of Astronomy and Space Science, University of Chinese Academy of Sciences , Beijing 100049, People’s Republic of ChinaSchool of Astronomy and Space Science, Nanjing University , Nanjing 210093, People’s Republic of China ; chengdong.li@nju.edu.cn; Key Laboratory of Modern Astronomy and Astrophysics (Nanjing University) , Ministry of Education, Nanjing 210093, People’s Republic of ChinaNational Astronomical Observatories , Chinese Academy of Sciences, Beijing 100101, People’s Republic of China ; gzhao@nao.cas.cn; School of Astronomy and Space Science, University of Chinese Academy of Sciences , Beijing 100049, People’s Republic of ChinaNational Astronomical Observatories , Chinese Academy of Sciences, Beijing 100101, People’s Republic of China ; gzhao@nao.cas.cn; School of Astronomy and Space Science, University of Chinese Academy of Sciences , Beijing 100049, People’s Republic of ChinaNational Astronomical Observatories , Chinese Academy of Sciences, Beijing 100101, People’s Republic of China ; gzhao@nao.cas.cn; Institute for Frontiers in Astronomy and Astrophysics, Beijing Normal University , Beijing 102206, People’s Republic of ChinaRecent observations indicate that both the Milky Way bulge and inner halo exhibit angular momentum, although the origin and evolution of this prograde signature remain ambiguous. One plausible scenario involves secular evolution induced by the central bar and spiral arms. In this study, we identified a component consisting of 1,175,737 stars with net rotation through the application of a neural network (NN) method. To investigate the composition of this rotating sample and the origin of its rotation, we conducted a test particle simulation incorporating an equilibrium axisymmetric background potential together with a central decelerating bar. The test particles were generated using a distribution function model derived from observational constraints. Our results indicate that the decelerating bar transfers angular momentum to the pseudo-stars, and the rotational profile from our simulation shows strong agreement with observational data. These findings suggest that the rotating sample identified by our NN model is predominantly comprised of bulge, halo, and thick disk stars, and that the central decelerating bar is pivotal in shaping the inner Galaxy’s kinematics through angular momentum transfer.https://doi.org/10.3847/1538-4357/ade430Galactic barGalactic bulgeMilky Way stellar haloMilky Way dynamics |
| spellingShingle | Zhuohan Li Chengdong Li Gang Zhao Ruizhi Zhang Xiang-Xiang Xue The Rotating Bulge and Halo in the Milky Way: Evidence of Angular Momentum Transferred from the Decelerating Bar The Astrophysical Journal Galactic bar Galactic bulge Milky Way stellar halo Milky Way dynamics |
| title | The Rotating Bulge and Halo in the Milky Way: Evidence of Angular Momentum Transferred from the Decelerating Bar |
| title_full | The Rotating Bulge and Halo in the Milky Way: Evidence of Angular Momentum Transferred from the Decelerating Bar |
| title_fullStr | The Rotating Bulge and Halo in the Milky Way: Evidence of Angular Momentum Transferred from the Decelerating Bar |
| title_full_unstemmed | The Rotating Bulge and Halo in the Milky Way: Evidence of Angular Momentum Transferred from the Decelerating Bar |
| title_short | The Rotating Bulge and Halo in the Milky Way: Evidence of Angular Momentum Transferred from the Decelerating Bar |
| title_sort | rotating bulge and halo in the milky way evidence of angular momentum transferred from the decelerating bar |
| topic | Galactic bar Galactic bulge Milky Way stellar halo Milky Way dynamics |
| url | https://doi.org/10.3847/1538-4357/ade430 |
| work_keys_str_mv | AT zhuohanli therotatingbulgeandhalointhemilkywayevidenceofangularmomentumtransferredfromthedeceleratingbar AT chengdongli therotatingbulgeandhalointhemilkywayevidenceofangularmomentumtransferredfromthedeceleratingbar AT gangzhao therotatingbulgeandhalointhemilkywayevidenceofangularmomentumtransferredfromthedeceleratingbar AT ruizhizhang therotatingbulgeandhalointhemilkywayevidenceofangularmomentumtransferredfromthedeceleratingbar AT xiangxiangxue therotatingbulgeandhalointhemilkywayevidenceofangularmomentumtransferredfromthedeceleratingbar AT zhuohanli rotatingbulgeandhalointhemilkywayevidenceofangularmomentumtransferredfromthedeceleratingbar AT chengdongli rotatingbulgeandhalointhemilkywayevidenceofangularmomentumtransferredfromthedeceleratingbar AT gangzhao rotatingbulgeandhalointhemilkywayevidenceofangularmomentumtransferredfromthedeceleratingbar AT ruizhizhang rotatingbulgeandhalointhemilkywayevidenceofangularmomentumtransferredfromthedeceleratingbar AT xiangxiangxue rotatingbulgeandhalointhemilkywayevidenceofangularmomentumtransferredfromthedeceleratingbar |