The last gravitational waves emitted in the coalescence of two black holes are quasi-normal ringing modes of the merged remnant. In general relativity, the mass and the spin of the remnant black hole uniquely determine the frequency and damping time of each radiated mode. The amplitudes of these modes are determined by the mass ratio of the system and the geometry of the coalescence. This paper is part I of an analysis that aims to compute the "excitation factors" associated with misaligned binary black hole coalescence. To simplify the analysis, we consider a large mass ratio system consisting of a non-spinning body of mass $μ$ that inspirals on a quasi-circular trajectory into a Kerr black hole of mass $M$ and spin parameter $a$, with $μ/M \ll 1$. Our goal is to understand how different modes are excited as a function of the black hole spin $a$ and an angle $I$ which characterizes the misalignment of the orbit with the black hole's spin axis. Though the large mass ratio limit does not describe the binaries that are being observed by gravitational-wave detectors today, this limit makes it possible to quickly and easily explore the binary parameter space, and to develop insight into how the system's late ringing waves depend on the binary's geometry. In this first analysis, we develop the worldline which the small body follows as it inspirals and then plunges into the large black hole. Our analysis generalizes earlier work by Ori and Thorne to describe how a non-equatorial circular inspiral transitions into a plunging trajectory that falls into the black hole. The worldlines which we develop here are used in part II as input to a time-domain black hole perturbation solver. This solver computes the gravitational waves generated by such inspirals and plunges, making it possible to characterize the modes which the coalescence excites.
Ringdown of a postinnermost stable circular orbit of a rapidly spinning black hole: Mass ratio dependence of higher harmonic quasinormal mode excitation
Self-forced evolutions of an implicit rotating source: A natural framework to model comparable and intermediate mass-ratio systems from inspiral through ringdown
Complex frequency evolution of direct waves from binary black hole mergers
The Australian National University（澳大利亚国立大学）；Perimeter Institute for Theoretical Physics（理论物理珀蒂默研究所）；California Institute of Technology（加州理工学院）；University of Cambridge（剑桥大学）
Phenomenology and origin of late-time tails in eccentric binary black hole mergers
Kavli Institute for Theoretical Physics, University of California Santa Barbara（加州大学圣塔芭芭拉分校卡弗里理论物理研究所）；University of Massachusetts, Dartmouth（麻省大学达特茅斯分校）；University of Rhode Island（罗德岛大学）；Max Planck Institute for Gravitational Physics (Albert Einstein Institute)（马克斯·普朗克引力物理学研究所（爱因斯坦研究所））；Niels Bohr International Academy, Niels Bohr Institute（尼尔斯·玻尔国际学院，尼尔斯·玻尔研究所）
在几个假设条件下，研究了由Plebauski-Demiauskiski解得到的Kerr-Newman-NUT黑洞解.利用最初为极值Kerr黑洞提出的扰动Kerr/CFT对应，研究了该黑洞微观熵的起源.近视界极值Kerr-Newman-NUT黑洞的等距性表明，渐近对称群可以用来计算维拉索罗代数的中心荷.此外，通过假设Frolov-Thorne真空，可以得到共形温度。然后利用Cardy公式得到与Bekenstein-Hawking熵相匹配的微观熵。我们还利用Cardy公式求出了熵的对数修正。然后在极限$ a \rightarrow 0 $下，恢复了Reissner-Nordström-NUT的极值解，并通过纤维坐标的增强得到了五维（5D）解.对该黑洞进行第二次对偶连续傅里叶变换，得到熵。最后，微观熵仍然符合5D黑洞解的面积律。因此，极值Reissner-Nordström-NUT解与CFT是全息对偶的。
Sagittarius A* near-infrared flares polarization as a probe of space-time I: Non-rotating exotic compact objects
CENTRA, Faculdade de Engenharia, Universidade do Porto（波尔图大学工程学院）；CENTRA, Departamento de Física, Instituto Superior Técnico-IST, Universidade de Lisboa-UL（里斯本大学高等技术学院物理系）；Institute of Physics, University of Tartu（塔尔图大学物理研究所）；Departamento de Física Teórica, Universidad Complutense de Madrid（马德里康普顿斯大学理论物理系）
