Related papers: Black hole spin: theory and observation
Astrophysical black holes do not exist in vacuum, and their motion is affected by the galactic environment. As a black hole moves it attracts stars and matter, creating a wake that, in turn, exerts an effective friction slowing down the…
We consider black holes resulting from binary black hole mergers. By fitting to numerical results we construct analytic formulas that predict the mass and spin of the final black hole. Our formulas are valid for arbitrary initial spins and…
[Abridged] [...] We study the mass and spin evolution of massive black holes within a semianalytical galaxy-formation model that follows the evolution of dark-matter halos along merger trees, as well as that of the baryonic components (hot…
The observation of gravitational-wave signals from merging black-hole binaries enables direct measurement of the properties of the black holes. An individual observation allows measurement of the black-hole masses, but only limited…
An energy $E=\omega J$ is derived for gravitational spin-orbit coupling by frame-dragging $\omega$ acting on angular momentum $J$. This interaction defines a no-boundary mechanism for linear acceleration of magnetized matter along the axis…
Studies of black hole superradiance often focus on the growth of a cloud in isolation, accompanied by the spin-down of the black hole. In this paper, we consider the additional effect of the accretion of matter and angular momentum from the…
This paper explores how time-varying increases in mass accretion onto rapidly spinning black holes influence their long-term spin evolution when affected by superradiance - a process where energy is extracted from the black hole by a…
Black holes are spun up by accreting matter and possibly spun-down by magnetic fields. In our work we consider the effect on black hole rotation of the two electromagnetic processes, Blandford-Znajek and Direct Magnetic Link, that differ in…
Most common formation channels of stellar mass black hole (BH) binaries like the ones observed by LIGO, often assume they are assembled from the direct collapse of massive pre-supernova stars. However, it is still unclear whether the final…
I report the discovery of a new effect of General Relativity which is important to understand very rapidly rotating (Kerr) black holes. The orbital velocity of a test particle is no longer a monotonic function of the orbit radius when the…
The spin of the final black hole in the coalescence of nonspinning black holes is determined by the ``residual'' orbital angular momentum of the binary. This residual momentum consists of the orbital angular momentum that the binary is not…
In this work, we study how the spin of particle modes influences particle creation, greybody factors, absorption, and evaporation of a black hole within the framework of modified electrodynamics in $f(R,T)$ gravity, recently proposed in…
The black hole spacetime is described by general relativity and characterized by two quantities: the black hole mass and spin. Black hole spin measurement requires information from the vicinity of the event horizon, which is spatially…
Black holes are extreme expressions of gravity. Their existence is predicted by Einstein's theory of general relativity and is supported by observations. Black holes obey quantum mechanics and evaporate spontaneously. Here it is shown that…
X-ray irradiation of the accretion disc leads to strong reflection features, which are then broadened and distorted by relativistic effects. We present a detailed, general relativistic approach to model this irradiation for different…
To date, there have been several detections of high-mass black hole binaries in both the Milky Way and other galaxies. For some of these, the spin parameter of the black hole has been estimated. As many of these systems are quite tight, a…
Black holes across a broad range of masses play a key role in the evolution of galaxies. The initial seeds of black holes formed at $z \sim 30$ and grew over cosmic time by gas accretion and mergers. Using observational data for quasars and…
We derive closed formulas for the mass and spin parameters of a Kerr black hole in terms of a minimal quantity of observational data: the red-/blue-shifts of photons emitted by massive particles (stars) moving on geodesics around the black…
We introduce a novel formalism to investigate the role of the spin angular momentum of astrophysical black holes in influencing the behaviour of low angular momentum general relativistic accretion. We propose a metric independent analysis…
We study the spin dependence of accretion onto rotating Kerr black holes using analytic techniques. In its linear regime, angular momentum transport in MHD turbulent accretion flow involves the generation of radial magnetic field connecting…