论文标题
测试黑洞合并质量分布的时间演变
Testing time evolution of the mass distribution of the black hole mergers
论文作者
论文摘要
对重力波事件的检测表明，有许多黑洞（BH）二进制组可以在宇宙时代内合并。尽管已知这种二进制文件的几个地层通道，但与每个通道相关的相关理论上不确定性都击败了对每个通道对总合并速率密度贡献多少的强大预测。鉴于某些通道中合并速率密度的时间演变与BH质量无关，因此从观察数据中阐明这一特征将阐明BH二进制文件的性质。在这种动机的基础上，我们制定了一种方法，以对BH合并的质量分布是否通过假设检验演变而演变。我们的统计检验既不需要对质量分布的先验规范，这在很大程度上不确定，也不需要合并率的时间依赖性。然后，我们将其应用于模拟数据的合并速率密度的某些具体形状，并表明所提出的方法拒绝/（不拒绝）对于大样本量，正确的零假设。经过此验证后，该方法应用于Ligo-Virgo第三次观测过程中获得的重力波事件的目录。我们发现，由于我们可以探索的合并事件的数量减少和最大红移，因此选择偏差会降低我们方法对O3目录的有效性。在可以应用该方法的范围内，没有迹象表明合并速率密度的质量分布的时间演变。在包含更多事件的未来观察结果中将缓解此限制，我们的假设检验将有助于确定合并速率密度是否随着时间的推移而独立于BH质量而演变。
The detection of gravitational-wave events revealed that there are numerous populations of black hole (BH) binaries that can merge within the age of the Universe. Although several formation channels of such binaries are known, considerable theoretical uncertainties associated with each channel defeat the robust prediction of how much each channel contributes to the total merger rate density. Given that the time evolution of the merger rate density in some channels is (exactly or nearly) independent of BH masses, clarifying this feature from observational data will shed some light on the nature of BH binaries. On the basis of this motivation, we formulate a methodology to perform a statistical test of whether the mass distribution of BH mergers evolves over time by hypothesis testing. Our statistical test requires neither a priori specification of the mass distribution, which is largely uncertain, nor that of the time dependence of merger rate. We then apply it to mock data for some concrete shapes of the merger rate density and show that the proposed method rejects/(does not reject) the null hypothesis correctly for a large sample size. After this verification, the method is applied to a catalog of the gravitational-wave events obtained during the LIGO-Virgo's third observing run. We find that the selection bias degrades the effectiveness of our method for the O3 catalog owing to the reduction in the number of and the maximum redshifts of the merger events that we can explore. Within the range where the method can be applied, there is no indication of the time evolution of the mass distribution of merger rate density. This limitation will be eased in future observations containing more events, and our hypothesis testing will help determine whether the merger rate density evolves over time independently of BH masses.
