QUANTIFYING KINEMATIC SUBSTRUCTURE IN THE MILKY WAY'S STELLAR HALO

	QUANTIFYING KINEMATIC SUBSTRUCTURE IN THE MILKY WAY'S STELLAR HALO
	Xue, Xiang-Xiang 1,2; Rix, Hans-Walter 2; Yanny, Brian 3; Beers, Timothy C.4,14; Bell, Eric F.2,5; Zhao, Gang 1; Bullock, James S.6; Johnston, Kathryn V.7; Morrison, Heather 8; Rockosi, Constance 9
刊名	ASTROPHYSICAL JOURNAL
	2011-09-01
卷号	738 期号:1 页码:79(12)
关键词	galaxies: individual (MilkyWay) Galaxy: halo Galaxy: structure stars: horizontal-branch stars: kinematics and dynamics
ISSN号	0004-637X
英文摘要	We present and analyze the positions, distances, and radial velocities for over 4000 blue horizontal-branch (BHB) stars in the Milky Way's halo, drawn from SDSS DR8. We search for position-velocity substructure in these data, a signature of the hierarchical assembly of the stellar halo. Using a cumulative "close pair distribution" as a statistic in the four-dimensional space of sky position, distance, and velocity, we quantify the presence of position-velocity substructure at high statistical significance among the BHB stars: pairs of BHB stars that are close in position on the sky tend to have more similar distances and radial velocities compared to a random sampling of these overall distributions. We make analogous mock observations of 11 numerical halo formation simulations, in which the stellar halo is entirely composed of disrupted satellite debris, and find a level of substructure comparable to that seen in the actually observed BHB star sample. This result quantitatively confirms the hierarchical build-up of the stellar halo through a signature in phase (position-velocity) space. In detail, the structure present in the BHB stars is somewhat less prominent than that seen in most simulated halos, quite possibly because BHB stars represent an older sub-population. BHB stars located beyond 20 kpc from the Galactic center exhibit stronger substructure than at r(gc) < 20 kpc.
学科主题	Astronomy & Astrophysics
WOS标题词	Science & Technology ; Physical Sciences
类目[WOS]	Astronomy & Astrophysics
研究领域[WOS]	Astronomy & Astrophysics
关键词[WOS]	DIGITAL SKY SURVEY ; HORIZONTAL-BRANCH STARS ; SURVEY COMMISSIONING DATA ; TRACING GALAXY FORMATION ; COLD DARK-MATTER ; DATA RELEASE ; GALACTIC HALO ; CIRCULAR VELOCITY ; DWARF GALAXY ; 1ST DATA
收录类别	SCI
语种	英语
WOS记录号	WOS:000294015500079
公开日期	2012-08-07
内容类型	期刊论文
源URL	[http://libir.pmo.ac.cn/handle/332002/4521]
专题	中国科学院紫金山天文台
作者单位	1.Chinese Acad Sci, Key Lab Opt Astron, Natl Astron Observ, Beijing 100012, Peoples R China 2.Max Planck Inst Astron, D-69117 Heidelberg, Germany 3.Fermilab Natl Accelerator Lab, Batavia, IL 60510 USA 4.Michigan State Univ, Dept Phys & Astron, E Lansing, MI 48824 USA 5.Univ Michigan, Dept Astron, Ann Arbor, MI 48109 USA 6.Univ Calif Irvine, Ctr Cosmol, Dept Phys & Astron, Irvine, CA 92697 USA 7.Columbia Univ, Dept Astron, New York, NY 10027 USA 8.Case Western Reserve Univ, Dept Astron, Cleveland, OH 44106 USA 9.Univ Calif Santa Cruz, Lick Observ, Santa Cruz, CA 95060 USA 10.Univ Cambridge, Inst Astron, Cambridge CB3 0HA, England
推荐引用方式 GB/T 7714	Xue, Xiang-Xiang,Rix, Hans-Walter,Yanny, Brian,et al. QUANTIFYING KINEMATIC SUBSTRUCTURE IN THE MILKY WAY'S STELLAR HALO[J]. ASTROPHYSICAL JOURNAL,2011,738(1):79(12).
APA	Xue, Xiang-Xiang.,Rix, Hans-Walter.,Yanny, Brian.,Beers, Timothy C..,Bell, Eric F..,...&Weaver, Benjamin A..(2011).QUANTIFYING KINEMATIC SUBSTRUCTURE IN THE MILKY WAY'S STELLAR HALO.ASTROPHYSICAL JOURNAL,738(1),79(12).
MLA	Xue, Xiang-Xiang,et al."QUANTIFYING KINEMATIC SUBSTRUCTURE IN THE MILKY WAY'S STELLAR HALO".ASTROPHYSICAL JOURNAL 738.1(2011):79(12).