An Inward-moving and Asymmetric Velocity Wave Detected in LAMOST-Gaia
The phase space, as coded by kinematic parameters and chemical abundances, is crucial for understanding the formation of the Galactic disk. Using red giant stars from the Galactic thin disk with [Fe/H] > − 0.8 and low- α ratios identified in LAMOST-Gaia, we detect numerous ridges and undulations...
| Main Authors: | , , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
IOP Publishing
2024-01-01
|
| Series: | The Astrophysical Journal Letters |
| Subjects: | |
| Online Access: | https://doi.org/10.3847/2041-8213/ad18a7 |
| _version_ | 1797357474026618880 |
|---|---|
| author | Yuqin Chen Gang Zhao Wenbo Wu Zixi Guo Haopeng Zhang Zhuohan Li |
| author_facet | Yuqin Chen Gang Zhao Wenbo Wu Zixi Guo Haopeng Zhang Zhuohan Li |
| author_sort | Yuqin Chen |
| collection | DOAJ |
| description | The phase space, as coded by kinematic parameters and chemical abundances, is crucial for understanding the formation of the Galactic disk. Using red giant stars from the Galactic thin disk with [Fe/H] > − 0.8 and low- α ratios identified in LAMOST-Gaia, we detect numerous ridges and undulations in the R – V _ϕ diagram coded by median V _R . Strikingly, the slope of these features changes from −22 km s ^−1 kpc ^−1 to −8 km s ^−1 kpc ^−1 at R ∼ 11.5 kpc. Accordingly, the R _g – V _ϕ plane, also coded by median V _R , reveals wave-like structures that propagate outwards in the inner disk but reverse direction and move inwards beyond R _g = 11.5 kpc. The most prominent feature is the G1 group, distinguished by its wider spread and negative median V _R at R _g ∼ 15 kpc, contrasting with the narrower G0 group that exhibits positive median V _R at R _g < 11.5 kpc. Furthermore, the [C/N] versus [Fe/H] relationship for the G1 group mirrors the opposite trend compared to the G0 group. Since [C/N] serves as a proxy for age, this contrasting behavior suggests an inverse age–metallicity relation for the G1 group. Comparison with the Sagittarius dwarf galaxy reveals that the G1 group possesses distinct [Mg/Fe] and [Al/Fe] ratios, yet its [C/N] versus [Fe/H] pattern is similar to that of the Sgr dwarf galaxy. Based on these observations, we proposed that the inward-moving and asymmetric velocity wave G1 might be linked to the minor merge of the Sagittarius galaxy. |
| first_indexed | 2024-03-08T14:45:40Z |
| format | Article |
| id | doaj.art-17c9df5617c94e568f38018da1405673 |
| institution | Directory Open Access Journal |
| issn | 2041-8205 |
| language | English |
| last_indexed | 2024-03-08T14:45:40Z |
| publishDate | 2024-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | The Astrophysical Journal Letters |
| spelling | doaj.art-17c9df5617c94e568f38018da14056732024-01-11T09:24:54ZengIOP PublishingThe Astrophysical Journal Letters2041-82052024-01-019611L410.3847/2041-8213/ad18a7An Inward-moving and Asymmetric Velocity Wave Detected in LAMOST-GaiaYuqin Chen0https://orcid.org/0000-0002-8442-901XGang Zhao1https://orcid.org/0000-0002-8980-945XWenbo Wu2https://orcid.org/0000-0002-3354-9492Zixi Guo3https://orcid.org/0009-0002-1534-7237Haopeng Zhang4https://orcid.org/0000-0003-3265-9160Zhuohan Li5https://orcid.org/0000-0002-1126-9289CAS Key Laboratory of Optical Astronomy, National Astronomical Observatories, Chinese Academy of Sciences , Beijing 100101, People’s Republic of China ; cyq@nao.cas.cn, gzhao@nao.cas.cn; School of Astronomy and Space Science, University of Chinese Academy of Sciences , Beijing 100049, People’s Republic of ChinaCAS Key Laboratory of Optical Astronomy, National Astronomical Observatories, Chinese Academy of Sciences , Beijing 100101, People’s Republic of China ; cyq@nao.cas.cn, gzhao@nao.cas.cn; School of Astronomy and Space Science, University of Chinese Academy of Sciences , Beijing 100049, People’s Republic of ChinaCAS Key Laboratory of Optical Astronomy, National Astronomical Observatories, Chinese Academy of Sciences , Beijing 100101, People’s Republic of China ; cyq@nao.cas.cn, gzhao@nao.cas.cn; School of Astronomy and Space Science, University of Chinese Academy of Sciences , Beijing 100049, People’s Republic of ChinaCAS Key Laboratory of Optical Astronomy, National Astronomical Observatories, Chinese Academy of Sciences , Beijing 100101, People’s Republic of China ; cyq@nao.cas.cn, gzhao@nao.cas.cn; School of Astronomy and Space Science, University of Chinese Academy of Sciences , Beijing 100049, People’s Republic of ChinaCAS Key Laboratory of Optical Astronomy, National Astronomical Observatories, Chinese Academy of Sciences , Beijing 100101, People’s Republic of China ; cyq@nao.cas.cn, gzhao@nao.cas.cn; School of Astronomy and Space Science, University of Chinese Academy of Sciences , Beijing 100049, People’s Republic of ChinaCAS Key Laboratory of Optical Astronomy, National Astronomical Observatories, Chinese Academy of Sciences , Beijing 100101, People’s Republic of China ; cyq@nao.cas.cn, gzhao@nao.cas.cn; School of Astronomy and Space Science, University of Chinese Academy of Sciences , Beijing 100049, People’s Republic of ChinaThe phase space, as coded by kinematic parameters and chemical abundances, is crucial for understanding the formation of the Galactic disk. Using red giant stars from the Galactic thin disk with [Fe/H] > − 0.8 and low- α ratios identified in LAMOST-Gaia, we detect numerous ridges and undulations in the R – V _ϕ diagram coded by median V _R . Strikingly, the slope of these features changes from −22 km s ^−1 kpc ^−1 to −8 km s ^−1 kpc ^−1 at R ∼ 11.5 kpc. Accordingly, the R _g – V _ϕ plane, also coded by median V _R , reveals wave-like structures that propagate outwards in the inner disk but reverse direction and move inwards beyond R _g = 11.5 kpc. The most prominent feature is the G1 group, distinguished by its wider spread and negative median V _R at R _g ∼ 15 kpc, contrasting with the narrower G0 group that exhibits positive median V _R at R _g < 11.5 kpc. Furthermore, the [C/N] versus [Fe/H] relationship for the G1 group mirrors the opposite trend compared to the G0 group. Since [C/N] serves as a proxy for age, this contrasting behavior suggests an inverse age–metallicity relation for the G1 group. Comparison with the Sagittarius dwarf galaxy reveals that the G1 group possesses distinct [Mg/Fe] and [Al/Fe] ratios, yet its [C/N] versus [Fe/H] pattern is similar to that of the Sgr dwarf galaxy. Based on these observations, we proposed that the inward-moving and asymmetric velocity wave G1 might be linked to the minor merge of the Sagittarius galaxy.https://doi.org/10.3847/2041-8213/ad18a7Milky Way diskStellar kinematicsMilky Way evolutionMilky Way dynamics |
| spellingShingle | Yuqin Chen Gang Zhao Wenbo Wu Zixi Guo Haopeng Zhang Zhuohan Li An Inward-moving and Asymmetric Velocity Wave Detected in LAMOST-Gaia The Astrophysical Journal Letters Milky Way disk Stellar kinematics Milky Way evolution Milky Way dynamics |
| title | An Inward-moving and Asymmetric Velocity Wave Detected in LAMOST-Gaia |
| title_full | An Inward-moving and Asymmetric Velocity Wave Detected in LAMOST-Gaia |
| title_fullStr | An Inward-moving and Asymmetric Velocity Wave Detected in LAMOST-Gaia |
| title_full_unstemmed | An Inward-moving and Asymmetric Velocity Wave Detected in LAMOST-Gaia |
| title_short | An Inward-moving and Asymmetric Velocity Wave Detected in LAMOST-Gaia |
| title_sort | inward moving and asymmetric velocity wave detected in lamost gaia |
| topic | Milky Way disk Stellar kinematics Milky Way evolution Milky Way dynamics |
| url | https://doi.org/10.3847/2041-8213/ad18a7 |
| work_keys_str_mv | AT yuqinchen aninwardmovingandasymmetricvelocitywavedetectedinlamostgaia AT gangzhao aninwardmovingandasymmetricvelocitywavedetectedinlamostgaia AT wenbowu aninwardmovingandasymmetricvelocitywavedetectedinlamostgaia AT zixiguo aninwardmovingandasymmetricvelocitywavedetectedinlamostgaia AT haopengzhang aninwardmovingandasymmetricvelocitywavedetectedinlamostgaia AT zhuohanli aninwardmovingandasymmetricvelocitywavedetectedinlamostgaia AT yuqinchen inwardmovingandasymmetricvelocitywavedetectedinlamostgaia AT gangzhao inwardmovingandasymmetricvelocitywavedetectedinlamostgaia AT wenbowu inwardmovingandasymmetricvelocitywavedetectedinlamostgaia AT zixiguo inwardmovingandasymmetricvelocitywavedetectedinlamostgaia AT haopengzhang inwardmovingandasymmetricvelocitywavedetectedinlamostgaia AT zhuohanli inwardmovingandasymmetricvelocitywavedetectedinlamostgaia |