论文标题
来自三体相互作用的原始黑洞合并
Primordial black hole mergers from three-body interactions
论文作者
论文摘要
当前的重力波观测在太阳质量范围内的原始黑洞(PBHS)中设定了最严格的边界。但是,这种约束本质上依赖于PBH模型预测的合并率。先前的分析主要集中在两种二元形成机制上:早期宇宙组装是出于当今的暗物质结构中的哈勃扩张和动态捕获的脱钩。使用在天体物理环境中研究的三体过程的反应速率,我们表明,在保守的假设下,PBH光环中的三体相互作用有效地产生二进制。这些二进制文件在泊松诱导的PBH小规模结构中形成高红移,并且预计将在宇宙当前时代内合并并合并一小部分,这与它们迅速合并的动态捕获场景不一致。通常,我们发现此通道预测速率与动态捕获方案相当。但是,除非PBHS占太阳质量范围以上的暗物质的主要部分,否则由三体相互作用形成的二进制物并不能显着促进总体PBH合并率,这是由当前约束所排除的情况。我们的结果支持了从激光干涉仪重力波观测/处女座/Kagra观测得出的恒星质量范围的PBH丰度的强度界限。最后,我们表明,与小行星质量范围内PBH合并的早期宇宙组装相比,这两个动力学通道总是次要的,而我们期望它在最初强烈聚集的PBH的情况下会变得相关。
Current gravitational-wave observations set the most stringent bounds on the abundance of primordial black holes (PBHs) in the solar mass range. This constraint, however, inherently relies on the merger rate predicted by PBH models. Previous analyses have focused mainly on two binary formation mechanisms: early Universe assembly out of decoupling from the Hubble expansion and dynamical capture in present-day dark matter structures. Using reaction rates of three-body processes studied in the astrophysical context, we show that, under conservative assumptions, three-body interactions in PBH halos efficiently produce binaries. Those binaries form at high redshift in Poisson-induced PBH small-scale structures and a fraction is predicted to coalesce and merge within the current age of the Universe, at odds with the dynamical capture scenario where they merge promptly. In general, we find that this channel predicts rates comparable to the dynamical capture scenario. However, binaries formed from three-body interactions do not significantly contribute to the overall PBH merger rate unless PBHs made up a dominant fraction of the dark matter above the solar mass range, a scenario that is ruled out by current constraints. Our results support strong bounds on the PBH abundance in the stellar mass range derived from Laser Interferometer Gravitational-Wave Observatory/Virgo/KAGRA observations. Finally, we show that both dynamical channels are always subdominant compared to early Universe assembly for PBH mergers in the asteroid mass range, while we expect it to become relevant in scenarios where PBHs are initially strongly clustered.