Related papers: Testing conformal gravity using the supermassive b…
In this article we study weak gravitational lensing of regular Bardeen black hole which has scalar charge $g$ and mass $m.$ We investigate the angular position and magnification of non-relativistic images in two cases depending on the…
General relativity predicts the spacetime metric around an astrophysical black hole to be described by the Kerr solution, which is a massive rotating black hole without any residual charge. In a previous paper, we analyzed the NuSTAR…
A new class of analytically expressible vacuum solutions has recently been discovered for pure ${R}^2$ gravity, building upon Buchdahl's seminal work from 1962. These solutions, inspired by Buchdahl's framework, offer a promising avenue for…
We present mass estimates of supermassive black holes in six nearby fast rotating early-type galaxies (NGC4339, NGC4434, NGC4474, NGC4551, NGC4578 and NGC4762) with effective stellar velocity dispersion around 100 km/s. We use near-infrared…
We study gravitational collapse for the Starobinsky $R^2$ model, a particular example of an $f(r)$ theory, in a spherically symmetric spacetime. We add a massless scalar field as matter content to the spacetime. We work in the Einstein…
We have constructed axisymmetric dynamical models of the edge-on S0 galaxy NGC 4342: simple two-integral Jeans models as well as fully general, three-integral models using a modified version of Schwarzschild's orbit superposition technique.…
The mass ($M_\mathrm{BH}$) of a supermassive black hole (SMBH) can be measured using spatially-resolved kinematics of the region where the SMBH dominates gravitationally. The most reliable measurements are those that resolve the smallest…
We numerically study a formation of near extremal horizons from a gravitational collapse of radially symmetric gravitational waves in $4+1$ dimensions within the framework of pure Einstein gravity with positive cosmological constant.…
Different massive black hole mass - host galaxy scaling relations suggest that the growth of massive black holes is entangled with the evolution of their host galaxies. The number of measured black hole masses is still limited, and…
We numerically investigate the interior of a four-dimensional, spherically symmetric charged black hole accreting neutral null fluid. Previous study by Marolf and Ori suggested that late infalling observers encounter an effective shock wave…
Detailed observations of phenomena involving black holes, be it via gravitational waves or more traditional electromagnetic means, can probe the strong field regime of the gravitational interaction. The prediction of features in such…
The Schwarzschild metric has a divergent energy density at the horizon, which motivates a new approach to black holes. If matter is spread uniformly throughout the interior of a supermassive black hole, with mass $M\sim M_\star= 2.34…
For conformally invariant gravity theories defined on Riemannian spacetime and having the Schwarzschild--de-Sitter (SdS) metric as a solution in the Einstein gauge, we consider whether one may conformally rescale this solution to obtain…
This is the first of series of papers in which we investigate stability of the spherically symmetric space-time with de Sitter center. Geometry, asymptotically Schwarzschild for large $r$ and asymptotically de Sitter as $r\to 0$, describes…
When starting with a static, spherically-symmetric ansatz, there are two types of black hole solutions in dRGT massive gravity: (i) exact Schwarzschild solutions which exhibit no Yukawa suppression at large distances and (ii) solutions in…
We present a completely integrable deformation of the CGHS dilaton gravity model in two dimensions. The solution is a singularity free black hole that at large distances asymptoticaly joins to the CGHS solution.
Binary pulsars allow us to carry out precision tests of gravity and have placed stringent bounds on a broad class of theories beyond general relativity. Current and future radio telescopes, such as FAST, SKA, and MeerKAT, may find a new…
In this paper, we study rotating black holes in symmergent gravity, and use deviations from the Kerr black hole to constrain the parameters of the symmergent gravity. Symmergent gravity induces the gravitational constant $G$ and quadratic…
We study the spherical collapse of a perfect fluid with an equation of state $P=k\rho$ by full general relativistic numerical simulations. For $0<k\alt 0.036$, it has been known that there exists a general relativistic counterpart of the…
We study scalar and electromagnetic perturbations of a family of nonsingular nonrotating black hole spacetimes that are solutions in a large class of conformally invariant theories of gravity. The effective potential for scalar…