大质量黑洞(MBH)双星螺旋内的时间尺度是不确定的,它们的自旋甚至更不受约束。自旋错位,以及不相等的质量比和自旋幅度,在引力辐射中引入了不对称性,这给合并的MBH带来了反冲。了解MBH双星自旋如何演化对于确定它们的反冲速度、LISA可探测到的引力波(GW)波形以及它们在星系中的合并后留存率以及随后的合并率至关重要。在这里,我们提出了一个新的研究,介绍了一个亚分辨率模型的气体和GW驱动的MBH二进制自旋演化使用人口的吸积MBH从插图宇宙流体动力学模拟。我们还通过动力学摩擦,恒星散射,粘性气体阻力和GW排放模型的次分辨率二进制inspiral。我们的模型假设微分吸积,这会导致更大的调整二级MBH自旋不等质量合并。我们发现在我们的人群中有47%的MBH通过$z=0$合并。其中,在我们的(保守的)基准模型中,19%的公司在合并时有未对齐的初选,10%的公司在合并时有未对齐的次级初选。然而,MBH失调分数强烈依赖于吸积盘参数。减少吸积率的一个因素的100,在一个较厚的光盘,产生79%和42%的初级和次级的错位,分别。即使在基准模型中,超过12%的双星经历了$>500$ km s $^{-1}$的反冲,这可能会使它们至少暂时离开星系核。我们还发现,大量的系统经历强进动。
英文摘要:
Massive black hole (MBH) binary inspiral time scales are uncertain, and their spins are even more poorly constrained. Spin misalignment, along with unequal mass ratios and spin magnitudes, introduces asymmetry in the gravitational radiation, which imparts a recoil kick to the merged MBH. Understanding how MBH binary spins evolve is crucial for determining their recoil velocities, their gravitational wave (GW) waveforms detectable with LISA, as well as their post-merger retention rate in galaxies and thus their subsequent merger rate. Here we present a novel study that introduces a sub-resolution model for gas- and GW-driven MBH binary spin evolution using a population of accreting MBHs from the Illustris cosmological hydrodynamics simulations. We also model sub-resolution binary inspiral via dynamical friction, stellar scattering, viscous gas drag, and GW emission. Our model assumes differential accretion, which causes greater alignment of the secondary MBH spin in unequal-mass mergers. We find that 47% of the MBHs in our population merge by $z=0$. Of these, 19% have misaligned primaries and 10% have misaligned secondaries at the time of merger in our (conservative) fiducial model. The MBH misalignment fraction depends strongly on the accretion disc parameters, however. Reducing accretion rates by a factor of 100, in a thicker disc, yields 79% and 42% misalignment for primaries and secondaries, respectively. Even in the fiducial model, more than 12% of binaries experience recoils of $>500$ km s$^{-1}$, which could displace them at least temporarily from galactic nuclei. We additionally find that a significant number of systems experience strong precession.
Probing supermassive stars and massive black hole seeds through gravitational wave inspirals
我们提出了一个新的引力波发射源:原始超大质量恒星内部致密碎片的螺旋辐射。这样的系统被认为是超大质量黑洞(SMBH)形成过程中的一个重要通道,但人们对此知之甚少。一个模型表明,在原子冷却的原始晕中,$0.1$-1 M $_\odot$ /yr的高吸积率可能导致核燃烧SMS的形成。这最终将通过相对论不稳定性发生坍缩,留下巨大的BH残留物。最近的模拟表明,超大质量恒星很少单独形成,而伴星甚至形成的黑洞可能会被捕获/吸积,并由于气体动力学摩擦而螺旋进入SMS核心。在这里,我们探讨了从这样的吸气产生的GW发射,这可能会探测SMS的形成和演化和第一个超大质量黑洞的种子。我们使用一个半解析的气体动力学摩擦模型的吸气在SMS来表征其属性。我们发现这样的来源可能是潜在的观察到即将到来的空间出生的GW探测器在其形成的红移与引力透镜的好处。密切相关的准恒星合并可能会产生更强的信号,尽管从其他高z事件中消除这种事件可能具有挑战性。
Relativistic Corrections to the Formation Rate of Extreme Mass-Ratio Inspirals
University of Chinese Academy of Sciences (UCAS)(中国科学院大学);Hangzhou Institute for Advanced Study, UCAS(杭州高等研究院,中国科学院大学);International Center for Theoretical Physics Asia-Pacific(亚太理论物理国际中心)
Massive stellar cannibals: How stellar mergers drive mass-loss in extremely massive stars
Université de Genève(日内瓦大学);Gravitational Wave Science Center (GWSC), Université de Genève(引力波科学中心(GWSC),日内瓦大学);IRAP, UMR 5277 CNRS and Université de Toulouse(天体物理研究所(IRAP),法国国家科学研究中心(CNRS)联合研究单位5277,图卢兹大学);Yale University(耶鲁大学)
Co-evolution of Nuclear Star Clusters and Massive Black Holes: Extreme Mass-Ratio Inspirals
Guangzhou University(广州大学);Key Laboratory for Astronomical Observation and Technology of Guangzhou(广州市天文观测与技术重点实验室);Astronomy Science and Technology Research Laboratory of Department of Education of Guangdong Province(广东省教育厅天文科学与技术研究实验室);Universitat Politècnica de València(瓦伦西亚理工大学);Max-Planck-Institute for Extraterrestrial Physics(马克斯·普朗克地外物理研究所)