Related papers: Superradiance in Modified Gravity (MOG)
Gravitational-wave astronomy plays a crucial role in early universe cosmology, dark matter detection, and black-hole merger studies. It is shown here that the heterodyne detection of the gravito-optic effect (employing an enhanced…
We consider general perturbations of a Schwarzschild black holes in the context of f(R) gravity. A reduced set of frame independent master variables are determined, which obey two closed wave equations - one for the transverse, trace-free…
We derive a relativistic field equation for the trace of the metric perturbation beyond the weak field approximation to the Einstein field equations. The dynamics is governed by a massive Klein-Gordon equation on curved space-time, where…
We consider non-commutating Simpson-Visser spacetime and study the superradiance phenomena and the shadow cast by the back hole associated with this modified spacetime. We extensively study the different aspects of the black hole associated…
In this paper we have examined spherical accretion onto Schwarzschild MOG Black Holes within the framework of Modified Gravity. Using isothermal test fluids, we analyze the behavior of the flow near the critical (sonic) point for various…
We explore strong gravity effects of the geodesic motion in the spacetime of rotating black holes in general relativity and braneworld gravity. We focus on the description of the motion in terms of three fundamental frequencies: The orbital…
The purpose of this chapter is to provide an overview of the exciting field of black hole quasi-normal modes and its capabilities to test general relativity in the 21st century. After motivating this line of research, we provide a…
Black hole ringdowns in extensions of General Relativity (GR) generically exhibit two distinct signatures: (1) theory-dependent shifts in the standard black-hole quasinormal modes, and (2) additional modes arising from extra fundamental…
We investigate in detail the mechanism of superradiance to render the instability of Kerr-de Sitter black holes in scalar-tensor gravity. Our results provide more clues to examine the scalar-tensor gravity in the astrophysical black holes…
We present a solution for rotating black holes in massive gravity. We first give a solution of massive gravity with one dynamical metric. Both metrics of this solution are expressed in the advanced Eddington-Finkelstein-like coordinates:…
In supergravity, charged rotating black holes are generically driven towards becoming extremal and supersymmetric through the emission of Hawking radiation. Eventually, as the black hole approaches the BPS bound and is close to becoming…
The spin energy extraction from a rotating black hole by amplification of scalar waves inside superradiance resonance wedge cavity (ring), followed by jet formation via magnetic reconnection assisted by the amplified scalar fields, is…
The analysis of flare start-times confirms the periods found years ago (Aschenbach et al., 2004) in the near-infrared and X-ray light-curves related to the Sgr A* black hole. The assignment of the frequencies found to radial and vertical…
Classical black hole spacetimes can be recovered from the classical limit of quantum scattering amplitudes in a low-energy effective field theory of gravity. In this work we compute, at first post-Minkowskian and dipole order, the metric…
The prediction of spacetime singularities, regions of infinite curvature where classical physics breaks down, is one of the most profound challenges in General Relativity (GR). In particular, black hole solutions such as the Schwarzschild…
We have studied quasinormal modes of spinor $\frac{1}{2}$, massless Dirac field perturbations of a black hole in massive gravity. The parameters of the theory, such as the mass of the black hole, the scalar charge of the black hole, mode…
The magnetic field is one of the most important constituents of the cosmic space and one of the main sources of the dynamics of interacting matter in the universe. The astronomical observations imply the existence of a strong magnetic…
Non-thermal magnetospheric processes in the vicinity of supermassive black holes have attracted particular attention in recent times. Gap-type particle acceleration accompanied by curvature and Inverse Compton radiation could in principle…
The $C$-metric is a boost-symmetric spacetime solution to the vacuum Einstein field equations which describes black holes that are uniformly accelerated under the tension of a cosmic string. Only recently the thermodynamics of accelerating…
We generalize the Chern-Simons modified gravity to the metric-affine case and impose projective invariance by supplementing the Pontryagin density with homothetic curvature terms which do not spoil topologicity. The latter is then broken by…