Related papers: Do floating orbits in extreme mass ratio binary bl…
A (charged) rotating black hole may be unstable against a (charged) massive scalar field perturbation due to the existence of superradiance modes. The stability property depends on the parameters of the system. In this paper, the…
The existence of stable bound orbits of test particles is one of the most characteristic properties in black hole spacetimes. In higher-dimensional black holes, due to the dimensionality of gravity, there is no stable bound orbit balanced…
The decay of extremal charged black holes has been a useful guidance to derive consistency conditions in quantum gravity. In de Sitter space it has been argued that requiring (extremal) charged Nariai black holes to decay without forming a…
We present the first magnetohydrodynamic simulation in which a circumbinary disk around a relativistic binary black hole feeds mass to individual accretion disks ("mini-disks") around each black hole. Mass flow through the accretion streams…
We investigate the orbital eccentricity evolution of supermassive black hole binaries within galactic environments. We analyze the dynamics in triaxial merger remnants and subsequent interactions with geometrically thick nuclear discs. We…
In a preceding paper we examined the question whether the spin-spin repulsion and the gravitational attraction of two aligned sub-extremal black holes can balance each other. Based on the solution of a boundary value problem for two…
When a stellar binary encounters a spinning black hole, interesting phenomena might result due to the mutual interaction between the binary spin, orbital angular momentum and the black hole spin. Here we consider such encounters between an…
It is demonstrated that, in the adiabatic approximation, non-Equatorial circular orbits of particles in the Kerr metric (i.e. orbits of constant Boyer-Lindquist radius) remain circular under the influence of gravitational radiation…
(abridged) We consider a secular orbital evolution of a supermassive binary black hole (SBBH) with unequal masses $M_p$ and $M_s < M_p$ in a central part of a non-spherical nuclear star cluster (NSC). When the mass of NSC inside the orbit…
Characterizing the properties of black holes is one of the most important science objectives for gravitational-wave observations. Astrophysical evidence suggests that black holes that are nearly extremal (i.e. spins near the theoretical…
Photon circular orbits, an extreme case of light deflection, are among the hallmarks of black holes and are known to play a central role in a variety of phenomena related to these extreme objects. The very existence of such orbits when…
Stellar-mass binary black holes may have circumbinary disks if formed through common-envelope evolution or within gaseous environments. Disks can drive binaries into wider and more eccentric orbits, while gravitational waves harden and…
As a black hole in a binary spirals in gradually from large separation, energy and angular momentum flow not only to infinity but also into or out of the hole. In addition, the hole's horizon area increases slowly during this process. In…
The extensive catalog of waveforms, with details of binary black hole inspiral and merger, offer an opportunity to understand black hole interactions beyond the large separation regime. We envision a research program that focuses on the…
The blazar OJ287 is the most promising (and the only) case for an extragalactic binary black hole system inspiralling under the action of gravitational radiation reaction. At present, though it is not possible to directly observe the binary…
The recent detections of gravitational waves from binary systems of black holes are in remarkable agreement with the predictions of General Relativity. In this pedagogical mini-review, I will go through the physics of the different phases…
Merging event horizons of the binary black holes is investigated. While recent development of the numerical study of the binary black hole coalescence has shown that their apparent horizons can orbit for many periods, we study the orbital…
We construct exact solutions that describe the near horizon region of extremal rotating black holes in Einstein-Born-Infeld theory. Using generalized Komar integrals, we extract the electric charge and angular momentum from the near horizon…
We study gravitational wave emission and the structure and formation of apparent horizons in orbiting black-hole binary systems in higher-dimensional general relativity. For this purpose we present an apparent horizon finder for use in…
We present a study of the gravitational time delay of arrival of signals from binary pulsar systems with rotating black hole companions. In particular, we investigate the strength of this effect (Shapiro delay) as a function of the…