Tracing Kinematic and Chemical Properties of Sagittarius Stream by K-Giants, M-Giants, and BHB stars

doi:10.3847/1538-4357/ab48e2

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	Tracing Kinematic and Chemical Properties of Sagittarius Stream by K-Giants, M-Giants, and BHB stars
	Yang,Chengqun 7,8; Xue,Xiang-Xiang 8; Li,Jing 5,6; Liu,Chao 7,8; Zhang,Bo 7,8; Rix,Hans-Walter 4; Zhang,Lan 8; Zhao,Gang 7,8; Tian,Hao 8; Zhong,Jing 3
刊名	The Astrophysical Journal
	2019-12-01
卷号	886 期号:2
关键词	Galaxy evolution Galaxy formation Galaxy stellar halos Galaxy kinematics Galaxy dynamics
ISSN号	0004-637X
DOI	10.3847/1538-4357/ab48e2
英文摘要	Abstract We characterize the kinematic and chemical properties of ～3000 Sagittarius (Sgr) stream stars, including K-giants, M-giants, and blue horizontal branch stars (BHBs), selected from SEGUE-2, Large Sky Area Multi-Object Fibre Spectroscopic Telescope, and Sloan Digital Sky Survey separately in Integrals-of-Motion space. The orbit of the Sgr stream is quite clear from the velocity vector in the X–Z plane. Stars traced by K-giants and M-giants show that the apogalacticon of the trailing steam is ～100 kpc. The metallicity distributions of Sgr K-giants, M-giants, and BHBs indicate that the M-giants are on average the most metal-rich population, followed by K-giants and BHBs. All of the K-giants, M-giants, and BHBs indicate that the trailing arm is on average more metal-rich than the leading arm, and the K-giants show that the Sgr debris is the most metal-poor part. The α-abundance of Sgr stars exhibits a similar trend with the Galactic halo stars at lower metallicity ([Fe/H] <～ ?1.0 dex), and then evolve down to lower [α/Fe] than disk stars at higher metallicity, which is close to the evolution pattern of the α-element of Milky Way dwarf galaxies. We find that VY and metallicity of K-giants have gradients along the direction of the line of sight from the Galactic center in the X–Z plane, and the K-giants show that VY increases with metallicity at [Fe/H] >～??1.5 dex. After dividing the Sgr stream into bright and faint streams according to their locations in equatorial coordinates, the K-giants and BHBs show that the bright and faint streams present different VY and metallicities, the bright stream is on average higher in VY and metallicity than the faint stream.
语种	英语
出版者	The American Astronomical Society
WOS记录号	IOP:0004-637X-886-2-AB48E2
内容类型	期刊论文
源URL	[http://ir.bao.ac.cn/handle/114a11/28652]
专题	中国科学院国家天文台
作者单位	1.LSST, 950 North Cherry Avenue, Tucson, AZ 85719, USA 2.Rudolf Peierls Centre for Theoretical Physics, Clarendon Laboratory, Parks Road, Oxford OX1 3PU, UK 3.Key Laboratory for Research in Galaxies and Cosmology, Shanghai Astronomical Observatory, Chinese Academy of Sciences, 80 Nandan Road, Shanghai 200030, People's Republic of China 4.Max-Planck-Institute for Astronomy K?nigstuhl 17, D-69117, Heidelberg, Germany 5.Chinese Academy of Sciences South America Center for Astronomy, National Astronomical Observatories, CAS, Beijing 100012, People's Republic of China 6.Physics and Space Science College, China West Normal University, 1 ShiDa Road, Nanchong 637002, People's Republic of China 7.School of Astronomy and Space Science, University of Chinese Academy of Sciences, 19A Yuquan Road, Shijingshan District, Beijing 100049, People's Republic of China; xuexx@nao.cas.cn 8.National Astronomical Observatories, Chinese Academy of Sciences, 20A Datun Road, Chaoyang District, Beijing 100101, People's Republic of China ycq@bao.ac.cn
推荐引用方式 GB/T 7714	Yang,Chengqun,Xue,Xiang-Xiang,Li,Jing,et al. Tracing Kinematic and Chemical Properties of Sagittarius Stream by K-Giants, M-Giants, and BHB stars[J]. The Astrophysical Journal,2019,886(2).
APA	Yang,Chengqun.,Xue,Xiang-Xiang.,Li,Jing.,Liu,Chao.,Zhang,Bo.,...&Chang,Jiang.(2019).Tracing Kinematic and Chemical Properties of Sagittarius Stream by K-Giants, M-Giants, and BHB stars.The Astrophysical Journal,886(2).
MLA	Yang,Chengqun,et al."Tracing Kinematic and Chemical Properties of Sagittarius Stream by K-Giants, M-Giants, and BHB stars".The Astrophysical Journal 886.2(2019).