During post-Newtonian evolution of a compact binary, a mass ratio different from 1 provides a second small parameter, which can lead to unexpected results. We present a statistics of supermassive black hole candidates, which enables us first to derive their mass distribution, then to establish a logarithmically even probability of the mass ratios at their encounter. In the mass ratio range (1/30,1/3) of supermassive black hole mergers representing 40% of all possible cases, the combined effect of spin-orbit precession and gravitational radiation leads to a spin-flip of the dominant spin during the inspiral phase of the merger. This provides a mechanism for explaining a large set of observations on X-shaped radio galaxies. In another 40%, with mass ratios (1/30,1/1000) a spin-flip never occurs, while in the remaining 20% of mergers with mass ratios (1/3,1) it may occur during the plunge. We analyze the magnitude of the spin-flip angle occurring during the inspiral as function of the mass ratio and original relative orientation of the spin and orbital angular momentum. We also derive a formula for the final spin at the end of the inspiral in this mass ratio range.
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。
Sensitivity of Weak Lensing Surveys to Gravitational Waves from Inspiraling Supermassive Black Hole Binaries
University of Southern California（南加州大学）；Jet Propulsion Laboratory, California Institute of Technology（加州理工学院喷气推进实验室）；California Institute of Technology（加州理工学院）
Effects of dark dipole radiation on eccentric supermassive black hole binary inspirals
School of Astronomy and Space Science, University of Chinese Academy of Sciences (UCAS)（中国科学院大学天文与空间科学学院）；School of Physics, Nanjing University（南京大学物理学院）
Chaotic imprints of dark matter in extreme mass-ratio inspirals
Başkent University（巴什肯特大学）；National University of Sciences and Technology（国立科学与技术大学）；National Observatory of Athens（雅典国家天文台）；Universidad Católica del Norte（北部天主教大学）；University of Science and Technology of China（中国科学技术大学）
Dark matter mounds from the collapse of supermassive stars: a general-relativistic analysis
Scuola Internazionale Superiore di Studi Avanzati (SISSA)（高等高级研究国际学院）；Istituto Nazionale di Fisica Nucleare (INFN), Sezione di Trieste（意大利国家核物理研究所的里雅斯特分部）；University of Amsterdam（阿姆斯特丹大学）；Institute for Fundamental Physics of the Universe (IFPU)（宇宙基础物理研究所）；Instituto de Fisica de Cantabria (CSIC-UC)（坎塔布里亚物理研究所）；INFN Sezione di Pisa（意大利国家核物理研究所比萨分部）
Electromagnetic Emission and Orbital Evolution of Eccentric Supermassive Black Hole Binaries in Retrograde Disks
Institute of Science and Technology Austria (ISTA)（奥地利科学技术研究院）；Niels Bohr International Academy, Niels Bohr Institute（尼尔斯·玻尔国际学院，尼尔斯·玻尔研究所）；Space Telescope Science Institute（太空望远镜科学研究所）；Johns Hopkins University（约翰斯·霍普金斯大学）；Columbia University（哥伦比亚大学）；New York University（纽约大学）
