论文标题
使用径向速度在二进制中揭示黑洞：一个测试用例
Using radial velocities to reveal black holes in binaries: a test case
论文作者
论文摘要
目标。巨型恒星的lamost光谱中的大径向速度变化已被用来推断出看不见的同伴的存在。其中一些已被提议作为可能的黑洞候选人。我们通过研究具有已知X射线对应物（UCAC4 721-037069）的一个候选者的分类来测试此选择。方法。我们从利物浦望远镜获得了时间分辨的光谱，并从Chandra天文台获得了5K观测，以完全限制轨道参数和该系统的X射线发射。结果。我们发现来源是可以归类为RS CVN的恒星二进制的。这位巨型恒星充满了罗氏叶，二进制质量比大于一个。该系统可能是带有对流信封的中间质量恒星稳定传质的一个例子。结论。仅使用径向速度识别候选黑洞会导致许多误报。在大多数情况下，光学轨道调制的存在，例如所有lamost候选者，都表明这是恒星二元。
Aims. Large radial velocity variations in the LAMOST spectra of giant stars have been used to infer the presence of unseen companions. Some of them have been proposed as possible black hole candidates. We test this selection by investigating the classification of the one candidate having a known X-ray counterpart (UCAC4 721-037069). Methods. We obtained time-resolved spectra from the Liverpool Telescope and a 5ks observation from the Chandra observatory to fully constrain the orbital parameters and the X-ray emission of this system. Results. We find the source to be an eclipsing stellar binary that can be classified as a RS CVn. The giant star fills its Roche Lobe and the binary mass ratio is greater than one. The system may be an example of stable mass transfer from an intermediate-mass star with a convective envelope. Conclusions. Using only radial velocity to identify black hole candidates can lead to many false positives. The presence of an optical orbital modulation, such as observed for all LAMOST candidates, will in most cases indicate that this is a stellar binary.
