Related papers: Spacetime and orbits of bumpy black holes
In general relativity without a cosmological constant, a classical theorem due to Hawking states that stationary black holes must be topologically spherical. This result is one of the several ingredients that collectively imply the…
We study the quasinormal mode spectrum and grey-body factors of black holes in an effectively quantum-corrected spacetime, focusing on the influence of near-horizon modifications on observable quantities. Employing scalar, electromagnetic,…
The EHT observation revealed event horizon-scale images of the supermassive black holes Sgr A* and M87* and these results are consistent with the shadow of a Kerr black hole as predicted by general relativity. However, Kerr-like rotating…
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…
The Hairy Kerr black hole is a novel black hole solution that depicts a rotating space-time encompassed by an axisymmetric fluid. It has significant observational importance and is an excellent candidate for an astrophysical black hole. Our…
This chapter provides a brief introduction to the Kerr spacetime and rotating black holes, touching on the most common coordinate representations of the spacetime metric and the key features of the geometry -- the presence of horizons and…
We study the quantum improvement of Kerr black holes with mass-dependent scale identifications in asymptotically safe gravity. We find that a physically sensible identification can only be a function of $Mr$ and the area $A=4\pi(r^2+a^2)$…
I review elements of the foundations of black-hole theory with attention to problematic issues, and describe some techniques which either seem to help with the difficulties or at least investigate their scope. The definition of black holes…
The multipole moments of black holes in general relativity obey certain consistency relations known as the no-hair theorems. The details of this multipolar structure are imprinted into the gravitational waves emitted by binary black holes,…
It is a common wisdom that properties of macroscopic bodies are well described by (semi)classical physics. As we have suggested this wisdom is not applicable to black holes. Despite being macroscopic, black holes are quantum objects. They…
The spacetime singularities in classical general relativity are inevitable, which are also predicated by the celebrated singularity theorems. However, it is general belief that singularities do not exist in the nature and they are the…
Stellar-mass black holes offer what is perhaps the best scenario to test theories of gravity in the strong-field regime. In particular, f(R) theories, which have been widely discuss in a cosmological context, can be constrained through…
Black holes are one of the most fascinating predictions of general relativity. They are the natural product of the complete gravitational collapse of matter and today we have a body of observational evidence supporting the existence of…
We show that four-dimensional black holes become stable below certain mass when the Einstein-Hilbert action is supplemented with higher-curvature terms. We prove this to be the case for an infinite family of ghost-free theories involving…
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…
We describe 4D evaporating black holes as quantum field configurations by solving the semi-classical Einstein equation $G_{\mu\nu}=8\pi G \langle \psi|T_{\mu\nu}|\psi \rangle$ and quantum matter fields in a self-consistent manner. As the…
According to the no-hair theorem, an astrophysical black hole is uniquely described by only two quantities, the mass and the spin. In this series of papers, we investigate a framework for testing the no-hair theorem with observations of…
The inspirals of ``small'' ($1 - 100 M_\odot$) compact bodies through highly relativistic orbits of massive (several $\times 10^5 M_\odot -$ several $\times 10^6 M_\odot$) black holes are among the most anticipated sources for the LISA…
Black holes (BH) are objects described by General Relativity (GR), particularly by the Kerr solution. However, this solution is based on simplifying assumptions. To achieve a more realistic approach, we investigate the impact of deviations…
We explore the quantum nature of black holes by introducing an effective framework that takes into account deviations from the classical results. The approach is based on introducing quantum corrections to the classical Schwarzschild…