Deciphering the last major invasion of the Milky Way

被引：159

作者：

Gilmore, G

Wyse, RFG

Norris, JE

机构：

[1] Univ Cambridge, Inst Astron, Cambridge CB3 0HA, England

[2] Johns Hopkins Univ, Dept Phys & Astron, Baltimore, MD 21218 USA

[3] Australian Natl Univ, Res Sch Astron & Astrophys, Mt Stromlo Observ, Weston, ACT 2611, Australia

来源：

ASTROPHYSICAL JOURNAL | 2002年 / 574卷 / 01期

关键词：

Galaxy : evolution; Galaxy : formation; Galaxy : kinematics and dynamics Galaxy : stellar content; Galaxy : structure; stars : kinematics;

D O I：

10.1086/342363

中图分类号：

P1 [天文学];

学科分类号：

0704 ;

摘要：

We present first results from a spectroscopic survey of similar to2000 F/G stars 0.5-5 kpc from the Galactic plane, obtained with the Two Degree Field facility on the Anglo-Australian Telescope. These data show the mean rotation velocity of the thick disk about the Galactic center a few kiloparsecs from the plane is very different than expected, being similar to100 km s(-1) rather than the predicted similar to180 km s(-1). We propose that our sample is dominated by stars from a disrupted satellite that merged with the disk of the Milky Way some 10-12 Gyr ago. We do not find evidence for the many substantial mergers expected in hierarchical clustering theories. We find yet more evidence that the stellar halo retains kinematic substructure, indicative of minor mergers.

引用

页码：L39 / L42

页数：4

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