Can We Distinguish Low-mass Black Holes in Neutron Star Binaries?
Can We Distinguish Low-mass Black Holes in Neutron Star Binaries?
复制标题
DOI：
10.3847/1538-4357/aab2b0
复制
发表时间：
2017-10
期刊：
影响因子：
--
通讯作者：
Huan Yang;W. East;L. Lehner
中科院分区：
文献类型：
--
作者：
Huan Yang;W. East;L. Lehner
从聚结的双中子星(NS)中探测到引力波(GWS)是引力波天文学的又一个里程碑。然而，由于LIGO目前对波形的合并/振铃部分不那么敏感，如果不诉诸关于底层致密天体群的假设，就不能轻易排除这种信号是由黑洞(BH)-NS双星产生的可能性。我们回顾了几个可能在3M⊙(大致是NS最大质量的上限)以下产生BHS的天体物理通道，以及这些通道的现有限制。我们表明，由于NS状态方程中的不确定性，在假定高级LIGO灵敏度的情况下，很难区分来自二元NS系统和具有相同组分质量的BH-NS系统的GW。这种简并性可以通过积累许多事件的统计数据以更好地约束状态方程来打破，或者通过对晚期螺旋信号到合并后信号具有更高灵敏度的第三代探测器来打破。我们还讨论了双星NS和低质量BH-NS合并之间在电磁(EM)对应体上的可能差异，认为在没有更好地理解潜在的天体物理过程的情况下，明确区分这两者将是一项挑战。
The detection of gravitational waves (GWs) from coalescing binary neutron stars (NS) represents another milestone in gravitational-wave astronomy. However, since LIGO is currently not as sensitive to the merger/ringdown part of the waveform, the possibility that such signals are produced by a black hole (BH)–NS binary can not be easily ruled out without appealing to assumptions about the underlying compact object populations. We review a few astrophysical channels that might produce BHs below 3 M⊙ (roughly the upper bound on the maximum mass of an NS), as well as existing constraints for these channels. We show that, due to the uncertainty in the NS equation of state, it is difficult to distinguish GWs from a binary NS system from those of a BH–NS system with the same component masses, assuming Advanced LIGO sensitivity. This degeneracy can be broken by accumulating statistics from many events to better constrain the equation of state, or by third-generation detectors with higher sensitivity to the late-spiral to post-merger signal. We also discuss the possible differences in electromagnetic (EM) counterparts between binary NS and low-mass BH–NS mergers, arguing that it will be challenging to definitively distinguish the two without better understanding of the underlying astrophysical processes.