Samsing J, Bartos I, D'Orazio D J, Haiman Z, Kocsis B, Leigh N W C, Liu B, Pessah M E, Tagawa H
Niels Bohr International Academy, Niels Bohr Institute, Copenhagen, Denmark.
Department of Physics, University of Florida, Gainesville, FL, USA.
Nature. 2022 Mar;603(7900):237-240. doi: 10.1038/s41586-021-04333-1. Epub 2022 Mar 9.
There is some weak evidence that the black hole merger named GW190521 had a non-zero eccentricity. In addition, the masses of the component black holes exceeded the limit predicted by stellar evolution. The large masses can be explained by successive mergers, which may be efficient in gas disks surrounding active galactic nuclei, but it is difficult to maintain an eccentric orbit all the way to the merger, as basic physics would argue for circularization. Here we show that active galactic nuclei disk environments can lead to an excess of eccentric mergers, if the interactions between single and binary black holes are frequent and occur with mutual inclinations of less than a few degrees. We further illustrate that this eccentric population has a different distribution of the inclination between the spin vectors of the black holes and their orbital angular momentum at merger, referred to as the spin-orbit tilt, compared with the remaining circular mergers.
有一些微弱的证据表明，名为GW190521的黑洞合并具有非零偏心率。此外，组成黑洞的质量超过了恒星演化预测的极限。大质量可以通过连续合并来解释，这在活跃星系核周围的气体盘中可能是有效的，但一直维持到合并时的偏心轨道是困难的，因为基础物理学认为轨道会趋于圆化。在这里我们表明，如果单黑洞与双黑洞之间的相互作用频繁且相互倾角小于几度，那么活跃星系核盘环境会导致偏心合并的数量过多。我们进一步说明，与其余的圆形合并相比，这种偏心合并群体在合并时黑洞自旋矢量与其轨道角动量之间的倾角（称为自旋-轨道倾角）分布有所不同。
