19 low mass hypervelocity star candidates from the first data release of the LAMOST survey
19 low mass hypervelocity star candidates from the first data release of the LAMOST survey
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DOI：
10.1088/1674-4527/15/8/018
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发表时间：
2015-06
影响因子：
1.8
通讯作者：
Yin-Bi Li;A. Luo;Gang Zhao;Youjun Lu;P. Wei;B. Du;Xiang Li;Yongheng Zhao;Zhanwen Han;Bo Wang;Yue Wu;Yong Zhang;Yong-Hui Hou;Yuefei Wang;Ming Yang
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文献类型：
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作者：
Yin-Bi Li;A. Luo;Gang Zhao;Youjun Lu;P. Wei;B. Du;Xiang Li;Yongheng Zhao;Zhanwen Han;Bo Wang;Yue Wu;Yong Zhang;Yong-Hui Hou;Yuefei Wang;Ming Yang
据信，超高速恒星是通过（双星）恒星与中心超大质量黑洞之间的动态相互作用从银河系中心喷射出来的。在本文中，我们报告了 LAMOST 定期巡天首次数据发布中发现的来自超过 100 万颗恒星的 19 颗低质量 F/G/K 型超高速候选恒星。我们通过假设非高斯自行误差分布以及高斯日心距离和径向速度误差分布，使用蒙特卡罗模拟确定每个候选者的无界概率。模拟结果表明，所有候选者的无界可能性均超过预期的50%，其中之一甚至有超过90%的概率超过逃逸速度。此外，我们将候选者的金属丰度与银河核球、盘、晕和球状星团的金属丰度分布函数进行比较，并得出结论，银河核球或盘可能是我们候选者的诞生地。
Hypervelocity stars are believed to be ejected out from the Galactic center through dynamical interactions between (binary) stars and the central supermassive black hole(s). In this paper, we report 19 low mass F/G/K type hypervelocity star candidates from over one million stars found in the first data release of the LAMOST regular survey. We determine the unbound probability for each candidate using a Monte-Carlo simulation by assuming a non-Gaussian proper-motion error distribution, and Gaussian heliocentric distance and radial velocity error distributions. The simulation results show that all the candidates have unbound possibilities over 50% as expected, and one of them may even exceed escape velocity with over 90% probability. In addition, we compare the metallicities of our candidates with the metallicity distribution functions of the Galactic bulge, disk, halo and globular clusters, and conclude that the Galactic bulge or disk is likely the birth place for our candidates.