ON THE SPATIAL DISTRIBUTION AND THE ORIGIN OF HYPERVELOCITY STARS
ON THE SPATIAL DISTRIBUTION AND THE ORIGIN OF HYPERVELOCITY STARS
复制标题
超高速恒星的空间分布和起源
DOI：
10.1088/0004-637x/709/2/1356
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发表时间：
2009-10
影响因子：
4.9
通讯作者：
Yu, Qingjuan
中科院分区：
文献类型：
--
作者：
Lu, Youjun;Zhang, Fupeng;Yu, Qingjuan
逃离银晕的超高速恒星（HVSs）是恒星与银河系中心大质量黑洞（MBH）相互作用的动力学产物。它们主要是b型恒星，它们的祖先未知。OB恒星也分布在GC中，其中许多位于距MBH半秒差距内顺时针旋转的年轻恒星（CWS）盘中，它们的形成仍然是一个谜。本文通过解析论证和数值模拟，证明了HVS能够很好地记忆其祖先的注入方向，即HVS的弹射方向几乎与其祖先的注入方向反平行。因此，HVSs的空间分布直接映射了其祖先亲本种群的空间分布。我们还发现，几乎所有发现的hvs在空间上都与位于两个薄磁盘平面上一致。其中一个平面的方向与（内部）CWS盘的方向一致，这表明大多数hvs起源于CWS盘或先前存在的与CWS盘方向相似的盘状恒星结构。其余的HVSs可能与GC中微型螺旋北臂的平面或CWS盘的外部弯曲部分所定义的平面有关。我们的研究结果不仅支持HVSs的GC起源，而且还暗示中央盘（或具有类似方向的盘结构）应该在过去的200 Myr中持续存在或经常恢复活力，这为恒星盘的形成增加了新的挑战，并为长期存在的气体燃料注入mbh提供了见解。
Hypervelocity stars (HVSs) escaping away from the Galactic halo are dynamical products of interactions of stars with the massive black hole(s) (MBH) in the Galactic Center (GC). They are mainly B-type stars with their progenitors unknown. OB stars are also populated in the GC, with many being hosted in a clockwise-rotating young stellar (CWS) disk within half a parsec from the MBH and their formation remaining puzzles. In this paper, we demonstrate that HVSs can well memorize the injecting directions of their progenitors using both analytical arguments and numerical simulations, i.e., the ejecting direction of an HVS is almost anti-parallel to the injecting direction of its progenitor. Therefore, the spatial distribution of HVSs maps the spatial distribution of the parent population of their progenitors directly. We also find that almost all the discovered HVSs are spatially consistent with being located on two thin disk planes. The orientation of one plane is consistent with that of the (inner) CWS disk, which suggests that most of the HVSs originate from the CWS disk or a previously existed disk-like stellar structure with an orientation similar to it. The rest of HVSs may be correlated with the plane of the northern arm of the mini-spiral in the GC or the plane defined by the outer warped part of the CWS disk. Our results not only support the GC origin of HVSs but also imply that the central disk (or the disk structure with a similar orientation) should persist or be frequently rejuvenated over the past 200 Myr, which adds a new challenge to the stellar disk formation and provides insights to the longstanding problem of gas fueling into MBHs.
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DOI：
10.1111/j.1365-2966.2007.12034.x
发表时间：
2007-05
影响因子：
4.8
作者：
Qingjuan Yu;P. Madau
通讯作者：
Qingjuan Yu;P. Madau
DOI：
10.1111/j.1365-2966.2007.12699.x
发表时间：
2007-09
期刊：
Proceedings of the International Astronomical Union
影响因子：
--
作者：
Ulf Lockmann;H. Baumgardt
通讯作者：
Ulf Lockmann;H. Baumgardt
DOI：
10.1088/0004-637x/690/1/l69
发表时间：
2008-11
期刊：
The Astrophysical Journal
影响因子：
--
作者：
Warren R. Brown;M. Geller;S. Kenyon;B. Bromley
通讯作者：
Warren R. Brown;M. Geller;S. Kenyon;B. Bromley
影响因子：
64.8
作者：
R. Sanders
通讯作者：
R. Sanders
影响因子：
56.9
作者：
P. Kroupa
通讯作者：
P. Kroupa