Kovetz Ely D
Department of Physics and Astronomy, Johns Hopkins University, 3400 North Charles Street, Baltimore, Maryland 21218, USA.
Phys Rev Lett. 2017 Sep 29;119(13):131301. doi: 10.1103/PhysRevLett.119.131301. Epub 2017 Sep 28.
Primordial black holes (PBHs) have long been suggested as a candidate for making up some or all of the dark matter in the Universe. Most of the theoretically possible mass range for PBH dark matter has been ruled out with various null observations of expected signatures of their interaction with standard astrophysical objects. However, current constraints are significantly less robust in the 20 M_{⊙}≲M_{PBH}≲100 M_{⊙} mass window, which has received much attention recently, following the detection of merging black holes with estimated masses of ∼30 M_{⊙} by LIGO and the suggestion that these could be black holes formed in the early Universe. We consider the potential of advanced LIGO (aLIGO) operating at design sensitivity to probe this mass range by looking for peaks in the mass spectrum of detected events. To quantify the background, which is due to black holes that are formed from dying stars, we model the shape of the stellar-black-hole mass function and calibrate its amplitude to match the O1 results. Adopting very conservative assumptions about the PBH and stellar-black-hole merger rates, we show that ∼5 yr of aLIGO data can be used to detect a contribution of >20 M_{⊙} PBHs to dark matter down to f_{PBH}<0.5 at >99.9% confidence level. Combined with other probes that already suggest tension with f_{PBH}=1, the obtainable independent limits from aLIGO will thus enable a firm test of the scenario that PBHs make up all of dark matter.
原初黑洞（PBHs）长期以来一直被认为是构成宇宙中部分或全部暗物质的候选者。PBH暗物质在理论上可能的大部分质量范围已通过对其与标准天体物理对象相互作用预期特征的各种零观测被排除。然而，在20M⊙≲MPBH≲100M⊙的质量窗口中，当前的限制明显不那么严格，最近这个窗口受到了很多关注，这是在LIGO探测到估计质量约为30M⊙的合并黑洞以及有人提出这些可能是早期宇宙中形成的黑洞之后。我们考虑以设计灵敏度运行的先进LIGO（aLIGO）通过寻找探测到的事件质量谱中的峰值来探测这个质量范围的潜力。为了量化由垂死恒星形成的黑洞所导致的背景，我们对恒星黑洞质量函数的形状进行建模，并校准其幅度以匹配O1结果。采用关于PBH和恒星黑洞合并率的非常保守的假设，我们表明，约5年的aLIGO数据可用于在>99.9%的置信水平下探测质量大于20M⊙的PBH对暗物质的贡献，直至fPBH<0.5。结合已经表明与fPBH = 1存在张力的其他探测方法，因此aLIGO可获得的独立限制将能够对PBH构成所有暗物质这一设想进行严格检验。
