Infalling clouds on to supermassive black hole binaries - II. Binary evolution and the final parsec problem
Infalling clouds on to supermassive black hole binaries - II. Binary evolution and the final parsec problem
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云层落入超大质量黑洞双星 - II。
DOI：
10.1093/mnras/stx1996
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发表时间：
2016
影响因子：
4.8
通讯作者：
F. Stasyszyn
中科院分区：
文献类型：
--
作者：
F. Goicovic;A. Sesana;J. Cuadra;F. Stasyszyn
大质量黑洞双星（MBHB）的形成是星系连续合并演化的必然结果。然而，驱动它们的轨道从秒差距分离到引力波（GW）占主导地位的机制知之甚少，它们的最终命运仍然不清楚。如果这样的双星嵌入在富含气体和湍流的环境中，就像在星系合并的残留物中观察到的那样，与气体团（如分子云）的相互作用可能会有效地驱动它们的轨道演化。使用数值模拟，我们测试这一假设，通过研究一个等质量，圆形MBHB吸积下落分子云的动力学演化。我们研究不同的轨道配置，共13个系统的建模，以探索不同的可能的影响参数和相对倾角的云二遇到。我们把我们的研究重点放在提示，瞬态阶段在第一个几个轨道时的动态演化的二进制是最快的，发现这种演变是由角动量的交换通过气体捕获的个别黑洞和吸积。在这些结果的基础上，我们构建了一个简单的模型，用于进化MBHB与云序列的相互作用，这些云序列是从合理的种群中随机抽取的，它们的角动量分布具有不同程度的各向异性。我们表明，二进制有效地发展到GW的排放制度在数亿年内，克服了“最后秒差距”的问题，无论恒星分布。
The formation of massive black hole binaries (MBHBs) is an unavoidable outcome of galaxy evolution via successive mergers. However, the mechanism that drives their orbital evolution from parsec separations down to the gravitational wave (GW) dominated regime is poorly understood, and their final fate is still unclear. If such binaries are embedded in gas-rich and turbulent environments, as observed in remnants of galaxy mergers, the interaction with gas clumps (such as molecular clouds) may efficiently drive their orbital evolution. Using numerical simulations, we test this hypothesis by studying the dynamical evolution of an equal-mass, circular MBHB accreting infalling molecular clouds. We investigate different orbital configurations, modelling a total of 13 systems to explore different possible impact parameters and relative inclinations of the cloud-binary encounter. We focus our study on the prompt, transient phase during the first few orbits when the dynamical evolution of the binary is fastest, finding that this evolution is dominated by the exchange of angular momentum through gas capture by the individual black holes and accretion. Building on these results, we construct a simple model for evolving a MBHB interacting with a sequence of clouds, which are randomly drawn from reasonable populations with different levels of anisotropy in their angular momenta distributions. We show that the binary efficiently evolves down to the GW emission regime within a few hundred million years, overcoming the 'final parsec' problem regardless of the stellar distribution.
影响因子：
4.8
作者：
F. Goicovic;F. Goicovic;Jorge Cuadra;A. Sesana;A. Sesana;F. Stasyszyn;P. Amaro-Seoane;Takamitsu L. Tanaka
通讯作者：
F. Goicovic;F. Goicovic;Jorge Cuadra;A. Sesana;A. Sesana;F. Stasyszyn;P. Amaro-Seoane;Takamitsu L. Tanaka