论文标题
Subparsec超级质量黑洞二进制候选的脉冲星时阵列限制
Pulsar Timing Array Constraints on the Merger Timescale of Subparsec Supermassive Black Hole Binary Candidates
论文作者
论文摘要
我们通过将其对重力波背景（GWB）的预期贡献与当前PULSAR时正时阵列（PTA）实验的敏感性进行比较，估算了光谱选择的，下质量的超级质量黑洞二进制（SMBHB）候选者的合并时间尺度，并与最新的上限狂潮相提并论。我们发现，这样的SmbHbs的平均时间尺度为$ \ langle t _ {\ rm evol} \ rangle> 6 \ times 10^4 \，$ yr，假设其PTA频带中的轨道演变是由重力浪潮发射驱动的。如果SMBHB的一小部分不在光谱检测到的活动星系中，并且它们在活动和不活跃星系中的发生率相似，那么合并时间表可能是$ \ sim 10 $ 10 $ t _ {$ \ langle t _ {\ rm evol} \ rm evol} \ rangle> 6 \ rangle> 6 \ times times 10^5^5^5 \ yrr。这些限制与理论模型预测的时间尺度范围一致，并暗示我们光谱样本中的所有SMBHB候选物可能是二进制的，而不会违反GWB上的观察性约束。该结果说明了由PTA促进的多通间测量方法的力量，在提供电磁搜索中发现的SMBHB候选物质的独立统计检验。
We estimate the merger timescale of spectroscopically-selected, subparsec supermassive black hole binary (SMBHB) candidates by comparing their expected contribution to the gravitational wave background (GWB) with the sensitivity of current pulsar timing array (PTA) experiments and in particular, with the latest upper limit placed by the North American Nanohertz Observatory for Gravitational Waves (NANOGrav). We find that the average timescale to coalescence of such SMBHBs is $\langle t_{\rm evol} \rangle > 6\times 10^4\,$yr, assuming that their orbital evolution in the PTA frequency band is driven by emission of gravitational waves. If some fraction of SMBHBs do not reside in spectroscopically detected active galaxies, and their incidence in active and inactive galaxies is similar, then the merger timescale could be $\sim 10$ times longer, $\langle t_{\rm evol} \rangle > 6\times 10^5\,$yr. These limits are consistent with the range of timescales predicted by theoretical models and imply that all the SMBHB candidates in our spectroscopic sample could be binaries without violating the observational constraints on the GWB. This result illustrates the power of the multi-messenger approach, facilitated by the PTAs, in providing an independent statistical test of the nature of SMBHB candidates discovered in electromagnetic searches.
