Gravitational waves from an SMBH binary in M87
Gravitational waves from an SMBH binary in M87
复制标题
来自 M87 中的SMBH双星的引力波
DOI：
10.1093/pasj/psw100
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发表时间：
2016
影响因子：
2.3
通讯作者：
K. Takahashi
中科院分区：
文献类型：
--
作者：
N. Yonemaru;H. Kumamoto;S. Kuroyanagi;K. Takahashi
我们研究了位于M 87中心的一个假设的超大质量黑洞双星的引力波发射。对于观测到的活动星系核与银河系质心之间的位移[∼O(1) Pc]，不同于通常被认为是中央活动星系核的SMBH的存在是一种可能的解释，考虑到SMBH的演化是通过星系合并而来的，这是合理的假设。由于双星和由此产生的GWS的周期比观测时间跨度长得多，所以我们计算的是GW振幅的变化，而不是振幅本身。在考虑观测约束的情况下，我们研究了它对轨道元素和第二BH质量的依赖关系。针对传统脉冲星计时阵列无法探测到的低频地磁场，提出了一种利用脉冲星自转速度分布函数来探测这种低频地磁场的新方法。尽管即使用新方法也很难探测到来自SMBH双星的GW来解释观测到的位移，但GW对于探测M 87中心仍然是有用的。
We study gravitational-wave (GW) emission from a hypothetical supermassive black-hole (SMBH) binary at the center of M 87. The existence of an SMBH other than that usually identified with the central active galactic nucleus (AGN) is a possible explanation for the observed displacement [∼O(1) pc] between the AGN and the galactic centroid, and it is reasonable to assume considering the evolution of SMBHs through galaxy mergers. Because the period of the binary and the resulting GWs is much longer than the observational time-span, we calculate the variation of the GW amplitude, rather than the amplitude itself. We investigate its dependence on the orbital elements and the second BH mass, taking the observational constraints into account. The frequency of the GWs is too low to be detected with the conventional pulsar timing array and we propose a new method for detecting such low-frequency GWs with the distribution function of pulsar spin-down rates. Although the GWs from an SMBH binary that explains the observed displacement are extremely hard to detect even by the new method, GWs are still useful for probing the M 87 center.