Anisotropy of the Milky Way’s Stellar Halo Using K Giants from LAMOST and Gaia
文献类型：期刊论文
| 作者 | Bird,Sarah A.1,2; Xue,Xiang-Xiang1,3; Liu,Chao1,3; Shen,Juntai2,3,4; Flynn,Chris5; Yang,Chengqun1,3 |
| 刊名 | The Astronomical Journal
 |
| 出版日期 | 2019-02-08 |
| 卷号 | 157期号:3 |
| 关键词 | galaxies: individual (Milky Way) Galaxy: halo Galaxy: kinematics and dynamics Galaxy: stellar content stars: individual (K giants) stars: kinematics and dynamics |
| ISSN号 | 0004-6256 |
| DOI | 10.3847/1538-3881/aafd2e |
| 英文摘要 | Abstract The anisotropy parameter β characterizes the extent to which orbits in stellar systems are predominantly radial or tangential and is likely to constrain, for the stellar halo of the Milky Way, scenarios for its formation and evolution. We have measured β as a function of Galactocentric radius from 5 to 100 kpc for 7664 metal-poor ([Fe/H]?< ?1.3) halo K giants from the LAMOST catalog with line-of-sight velocities and distances, matched to proper motions from the second Gaia data release. We construct full 6D positions and velocities for the K giants to directly measure the three components of the velocity dispersion (σr, σθ, σ?) (in spherical coordinates). We find that the orbits in the halo are radial over our full Galactocentric distance range reaching over 100 kpc. The anisotropy remains remarkably unchanged with Galactocentric radius from approximately 5–25 kpc, with an amplitude that depends on the metallicity of the stars, dropping from β?≈?0.9 for ?1.8?≤?[Fe/H]? |
| 语种 | 英语 |
| WOS记录号 | IOP:0004-6256-157-3-AAFD2E |
| 出版者 | The American Astronomical Society |
| 源URL | [http://119.78.226.72/handle/331011/31929]  |
| 专题 | 中国科学院上海天文台 |
| 作者单位 | 1.Key Laboratory of Optical Astronomy, National Astronomical Observatories, Chinese Academy of Sciences, 20A Datun Road, Beijing 100012, People's Republic of China; xuexx@nao.cas.cn, liuchao@nao.cas.cn 2.Shanghai Astronomical Observatory, 80 Nandan Road, Shanghai 200030, People's Republic of China; sarahbird@nao.cas.cn, jshen@shao.ac.cn 3.School of Astronomy and Space Science, University of Chinese Academy of Sciences, 19A Yuquan Road, Beijing 100049, People’s Republic of China 4.Department of Astronomy, School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, People’s Republic of China 5.Centre for Astrophysics and Supercomputing, Swinburne University of Technology, P.O. Box 218, Hawth |
| 推荐引用方式 GB/T 7714 | Bird,Sarah A.,Xue,Xiang-Xiang,Liu,Chao,et al. Anisotropy of the Milky Way’s Stellar Halo Using K Giants from LAMOST and Gaia[J]. The Astronomical Journal,2019,157(3). |
| APA | Bird,Sarah A.,Xue,Xiang-Xiang,Liu,Chao,Shen,Juntai,Flynn,Chris,&Yang,Chengqun.(2019).Anisotropy of the Milky Way’s Stellar Halo Using K Giants from LAMOST and Gaia.The Astronomical Journal,157(3). |
| MLA | Bird,Sarah A.,et al."Anisotropy of the Milky Way’s Stellar Halo Using K Giants from LAMOST and Gaia".The Astronomical Journal 157.3(2019). |
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来源：上海天文台
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