LIGO, California Institute of Technology, Pasadena, California 91125, USA.
Louisiana State University, Baton Rouge, Louisiana 70803, USA.
Phys Rev Lett. 2019 Oct 18;123(16):161102. doi: 10.1103/PhysRevLett.123.161102.
We present a search for subsolar mass ultracompact objects in data obtained during Advanced LIGO's second observing run. In contrast to a previous search of Advanced LIGO data from the first observing run, this search includes the effects of component spin on the gravitational waveform. We identify no viable gravitational-wave candidates consistent with subsolar mass ultracompact binaries with at least one component between 0.2 M_{⊙}-1.0 M_{⊙}. We use the null result to constrain the binary merger rate of (0.2 M_{⊙}, 0.2 M_{⊙}) binaries to be less than 3.7×10^{5} Gpc^{-3} yr^{-1} and the binary merger rate of (1.0 M_{⊙}, 1.0 M_{⊙}) binaries to be less than 5.2×10^{3} Gpc^{-3} yr^{-1}. Subsolar mass ultracompact objects are not expected to form via known stellar evolution channels, though it has been suggested that primordial density fluctuations or particle dark matter with cooling mechanisms and/or nuclear interactions could form black holes with subsolar masses. Assuming a particular primordial black hole (PBH) formation model, we constrain a population of merging 0.2 M_{⊙} black holes to account for less than 16% of the dark matter density and a population of merging 1.0 M_{⊙} black holes to account for less than 2% of the dark matter density. We discuss how constraints on the merger rate and dark matter fraction may be extended to arbitrary black hole population models that predict subsolar mass binaries.
我们展示了在高级 LIGO 第二次观测运行期间获得的数据中对亚太阳质量超紧凑物体的搜索结果。与之前对高级 LIGO 首次观测运行数据的搜索相比，此次搜索包括了组成部分自旋对引力波波形的影响。我们没有发现与至少一个组件在 0.2 M_{⊙}-1.0 M_{⊙}之间的亚太阳质量超紧凑双星一致的可行引力波候选物。我们利用这一零结果，将 (0.2 M_{⊙}, 0.2 M_{⊙}) 双星的合并率限制在小于 3.7×10^{5} Gpc^{-3} yr^{-1}，将 (1.0 M_{⊙}, 1.0 M_{⊙}) 双星的合并率限制在小于 5.2×10^{3} Gpc^{-3} yr^{-1}。亚太阳质量超紧凑物体预计不会通过已知的恒星演化通道形成，尽管有人提出原始密度波动或具有冷却机制和/或核相互作用的粒子暗物质可能会形成亚太阳质量的黑洞。假设特定的原始黑洞 (PBH) 形成模型，我们将限制合并的 0.2 M_{⊙} 黑洞的数量，使其占暗物质密度的比例小于 16%，并将合并的 1.0 M_{⊙} 黑洞的数量限制在暗物质密度的 2%以下。我们讨论了如何将合并率和暗物质分数的约束扩展到预测亚太阳质量双星的任意黑洞种群模型。
