EVIDENCE FOR AN ACCRETION ORIGIN FOR THE OUTER HALO GLOBULAR CLUSTER SYSTEM OF M31
EVIDENCE FOR AN ACCRETION ORIGIN FOR THE OUTER HALO GLOBULAR CLUSTER SYSTEM OF M31
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DOI：
10.1088/2041-8205/717/1/l11
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发表时间：
2010-05
期刊：
影响因子：
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通讯作者：
D. Mackey;A. Huxor;A. Ferguson;M. Irwin;N. Tanvir;A. McConnachie;R. Ibata;S. Chapman;G. Lewis-G.
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文献类型：
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作者：
D. Mackey;A. Huxor;A. Ferguson;M. Irwin;N. Tanvir;A. McConnachie;R. Ibata;S. Chapman;G. Lewis-G.
我们使用一个新发现的球状星团的样本从泛仙女座考古调查（PAndAS）结合以前编目的对象映射球状星团的空间分布在M31晕。在投影半径超过30 kpc的地方，大的相干恒星流在视野中很容易区分，这些特征和球状星团的位置之间有着惊人的相关性。采用一个简单的蒙特卡罗方法，我们测试的意义，这种关联计算的概率，它可能是由于机会对准球状星团顺利分布在M31晕。我们发现，这种可能性的可能性很低，低于1%，并得出结论，观察到的球状星团和多个潮汐碎屑流之间的空间重合的外晕的M31反映了一个真正的物理协会。我们的研究结果表明，大多数的远程球状星团系统的M31已组装作为一个结果的吸积的星团轴承卫星星系。这构成了迄今为止最直接的证据，证明一些星系中的外晕球状星团人口在很大程度上是吸积的。
We use a sample of newly discovered globular clusters from the Pan-Andromeda Archaeological Survey (PAndAS) in combination with previously cataloged objects to map the spatial distribution of globular clusters in the M31 halo. At projected radii beyond ≈30 kpc, where large coherent stellar streams are readily distinguished in the field, there is a striking correlation between these features and the positions of the globular clusters. Adopting a simple Monte Carlo approach, we test the significance of this association by computing the probability that it could be due to the chance alignment of globular clusters smoothly distributed in the M31 halo. We find that the likelihood of this possibility is low, below 1%, and conclude that the observed spatial coincidence between globular clusters and multiple tidal debris streams in the outer halo of M31 reflects a genuine physical association. Our results imply that the majority of the remote globular cluster system of M31 has been assembled as a consequence of the accretion of cluster-bearing satellite galaxies. This constitutes the most direct evidence to date that the outer halo globular cluster populations in some galaxies are largely accreted.