Related papers: Revisiting the semiclassical gravity scenario for …
Scalar-tensor theories of gravity generally violate the strong equivalence principle, namely compact objects have a suppressed coupling to the scalar force, causing them to fall slower. A black hole is the extreme example where such a…
The general theory of matching conditions is developed for gravitational theories in two spacetime dimensions. Models inspired from general relativity and from string theory are considered. These conditions are used to study collapsing dust…
Black hole evaporation may lead to massive or massless remnants, or naked singularities. This paper investigates this process in the context of two quite different two dimensional black hole models. The first is the original CGHS model, the…
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 develop here a procedure to obtain regular static configurations as resulting from dynamical gravitational collapse of a massive matter cloud in general relativity. Under certain general physical assumptions for the collapsing cloud, we…
We review the status of the weak cosmic censorship conjecture, which asserts, in essence, that all singularities of gravitational collapse are hidden within black holes. Although little progress has been made toward a general proof (or…
We treat here general relativistically the issue of galaxy formation, which is a major problem in cosmology. While the current models use a top-hat collapse model, coupled with Newtonian virialization technique to balance the…
In this work, we propose a model of the gravitational collapse of dark matter in the presence of quintessence or phantom-like scalar fields. Our treatment is based on the principles of general relativity up to virialization. We have chosen…
Astrophysical black hole candidates, although long thought to have a horizon, could be horizonless ultra-compact objects. This intriguing possibility is motivated by the black hole information paradox and a plausible fundamental connection…
A point of view is presented, according to which, the well known picture with the Schwarzschild black hole in canonical general relativity is one in a whole class of conformal representations of the same physical situation, that are…
General Relativity provides us with some solutions for rotating black holes. However, there are some problems associated with them: the appearance of singularities, the possibility of violations of the cosmic censorship conjecture, the…
Black holes in General Relativity are described by space-time metrics that are simpler in comparison to non-vacuum compact objects. However, given the universality of the gravitational pull, it is expected that dark matter accumulates…
It is well known that the concept of black hole has been considered very fascinating by scientists even before the introduction of Einstein's general relativity. They should be the final result of an irreversible gravitational collapse of…
End state of gravitational collapse and the related cosmic censorship conjecture continue to be amongst the most important open problems in gravitation physics today. My purpose here is to bring out several aspects related to gravitational…
A class of exact regular spherically symmetric solutions to the Einstein equation obeying Dymnikova's definition of the vacuumlike state is considered. These solutions, which may be interpreted as black holes, are not only singularity free,…
Black hole solutions in the context of a generic matter-coupled two-dimensional dilaton gravity theory are discussed both at the classical and semiclassical level. Starting from general assumptions, a criterion for the existence of black…
Starting with the conceptual foundation of general relativity (GR) - equivalence principle, space-time geometry and special relativity, I train cross hairs on two characteristic predictions of GR - black holes and gravitational waves. These…
General relativity (GR) passed many astronomical tests but in majority of them GR predictions have been tested in a weak gravitational field approximation. Around 50 years ago a shadow has been introduced by J. Bardeen as a purely…
It is shown that space curvature can be disposed of by properly taking into account gravitational self energies. This leads to a parameter free modification of Newton's law, violating Gauss theorem, which accounts for the crucial tests of…
We describe the possible forms of black hole images, viewed by a distant observer. These images are numerically calculated basing on general relativity and equations of motion in the Kerr-Newman metric. Black hole image is a gravitationally…