Ripple Patterns in In-plane Velocities of OB Stars from LAMOST and Gaia

doi:10.3847/2041-8213/ab020e

CORC > 国家天文台 > 中国科学院国家天文台

	Ripple Patterns in In-plane Velocities of OB Stars from LAMOST and Gaia
	Cheng,Xinlun 1; Liu,Chao 2; Mao,Shude 1,3; Cui,Wenyuan 4
刊名	The Astrophysical Journal Letters
	2019-02-06
卷号	872 期号:1
关键词	Galaxy: disk Galaxy: kinematics and dynamics Galaxy: structure
ISSN号	2041-8205
DOI	10.3847/2041-8213/ab020e
英文摘要	Abstract With about 12,000 OB type stars selected from the LAMOST and Gaia survey, we study their three-dimensional velocity distribution over the range of galactocentric radius from 6 to 15 kpc in the Galactic disk plane. A clear ripple pattern in the radial velocity (VR) map is shown. The median VR reaches ?8 km?s?1 at R?～?9 kpc, then increases to ～0 km?s?1 at R?～?12 kpc, and later declines to below ?10 km?s?1 beyond R?～?13 kpc. The median azimuthal velocity (V?) map shows a similar pattern but has roughly one-quarter phase difference with the radial velocity. Although the ripple of negative VR at ～9 kpc extends to about 40? in the azimuth angle, it does not align with either the Local or the Perseus spiral arms. Moreover, the farther ripple beyond 13 kpc does not match the Outer spiral arm either. This indicates that the non-axisymmetric kinematic features are not induced by perturbations of known spiral structures. The central rotating bar cannot lead to such patterns in the outer disk either. External perturbation of a dwarf galaxy or a dark matter sub-halo can induce such patterns, but this requires more evidence from both observations and simulations. The V? map in the Z–VZ plane of the OB stars is also investigated. Despite asymmetry to some degree, no spiral pattern is found. This is reasonable as most of the OB stars have ages that are much younger than 100 Myr, which is smaller than one orbital period around the Galactic center.
语种	英语
出版者	The American Astronomical Society
WOS记录号	IOP:2041-8205-872-1-AB020E
内容类型	期刊论文
源URL	[http://ir.bao.ac.cn/handle/114a11/25014]
专题	中国科学院国家天文台
作者单位	1.Physics Department and Tsinghua Centre for Astrophysics, Tsinghua University, Beijing 100084, People's Republic of China; liuchao@nao.cas.cn 2.Key Laboratory for Optical Astronomy, National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012, People's Republic of China 3.National Astronomical Observatories, Chinese Academy of Sciences, 20A Datun Road, Chaoyang District, Beijing 100012, People's Republic of China 4.Department of Physics, Hebei Normal University, Shijiazhuang 050024, People's Republic of China
推荐引用方式 GB/T 7714	Cheng,Xinlun,Liu,Chao,Mao,Shude,et al. Ripple Patterns in In-plane Velocities of OB Stars from LAMOST and Gaia[J]. The Astrophysical Journal Letters,2019,872(1).
APA	Cheng,Xinlun,Liu,Chao,Mao,Shude,&Cui,Wenyuan.(2019).Ripple Patterns in In-plane Velocities of OB Stars from LAMOST and Gaia.The Astrophysical Journal Letters,872(1).
MLA	Cheng,Xinlun,et al."Ripple Patterns in In-plane Velocities of OB Stars from LAMOST and Gaia".The Astrophysical Journal Letters 872.1(2019).