Massive binary black holes in galactic nuclei and their path to coalescence
Monica Colpi
备注：
Accepted for publication in Space Science Reviews. To appear in hard cover in the Space Sciences Series of ISSI "The Physics of Accretion onto Black Holes" (Springer Publisher)
Massive binary black holes form at the centre of galaxies that experience a merger episode. They are expected to coalesce into a larger black hole, following the emission of gravitational waves. Coalescing massive binary black holes are among the loudest sources of gravitational waves in the Universe, and the detection of these events is at the frontier of contemporary astrophysics. Understanding the black hole binary formation path and dynamics in galaxy mergers is therefore mandatory. A key question poses: during a merger, will the black holes descend over time on closer orbits, form a Keplerian binary and coalesce shortly after? Here we review progress on the fate of black holes in both major and minor mergers of galaxies, either gas-free or gas-rich, in smooth and clumpy circum-nuclear discs after a galactic merger, and in circum-binary discs present on the smallest scales inside the relic nucleus.
Supermassive black holes coalescence mediated by massive perturbers: implications for gravitational waves emission and nuclear cluster formation
很大一部分的星系核被认为是超大质量黑洞双星（BHB）的宿主，它们可能是在星系组装和合并的早期阶段形成的。在本文中，我们使用了一个大的国家的最先进的数值模型来调查之间的相互作用的BHB和一个大质量的星团（GC）驱动的银河系中心的动力学摩擦。改变BHB的质量和质量比和GC轨道，我们表明，GC和BHB之间施加的相互反馈形状的整体性能。我们发现，在GC-BHB质量比高于0.1，GC显着影响BHB轨道演化，可能会促进其合并。如果GC在逆行轨道上移动，并且对于不相等质量的BHB，这种效应最大化。我们发现，GC碎片分散在星系核周围，可以导致形成一个核簇，这取决于BHB潮汐场，并从GC中断产生的紧凑的残余物的分布可以携带有关BHB轨道特性的信息。我们发现，红巨星交付的螺旋GC可以被打乱的速度为$\simeq (0.7-7)\times 10^{-7}$年$^{-1}$的BHB质量$\sim 10^7{\rm M}_\odot$，而几十到几百颗恒星可能被观察到的星系晕中的高速恒星，速度高达$\sim 2000$ km s $^{-1}$，这取决于BHB的轨道特性。
Star clusters as tracers of galactic nuclei properties
我们提出了一系列的$N$体模拟代表的星系核和它的恒星内容的演变，在一个接近一对一的表示。这套模拟的目的是揭示核团（NC），超大质量黑洞（SMBH）和它们所包含的星系核之间的相互作用。我们模拟的星系质量从几倍$10^8$到$10^{11}$ M $_\odot$，在它们的核中有一些球状星团，在某些情况下，还有一个中央SMBH。
