相关论文: On the nature of inner light-rings

In general relativity, the Kerr metric uniquely represents the geometry surrounding an isolated, rotating black hole. An identification of significant non-Kerr features in some astrophysical source would then provide a `smoking-gun' for the…

We show that the number of horizons of static black holes can be strongly constrained by energy conditions of matter fields. After a careful clarification on the "interior" of a black hole, we prove that if the interior of a static black…

The images of supermassive black holes surrounded by optically-thin, radiatively-inefficient accretion flows, like those observed with the Event Horizon Telescope, are characterized by a bright ring of emission surrounding the black-hole…

We consider a globally hyperbolic, stationary spacetime containing a black hole but no white hole. We assume, further, that the event horizon, $\tn$, of the black hole is a Killing horizon with compact cross-sections. We prove that if…

Using a noncommutative inspired Einstein-Euler-Heisenberg black hole, we analyse the associated graviton and light rings that together with the event horizon, provide the necessary components to build its shadow. An analysis of the angular…

We study charged scalar perturbations of charged extremal black holes in Einstein-Born-Infeld theory. Our numerical results indicate that these black holes all suffer from superradiant instability by the unstable quasi-bound states,…

In this talk, we recall the most important features of the Dilatonic Black Holes which arise in the framework of the Einstein-Dilaton-Gauss-Bonnet theory and which are dressed with a classical long range dilaton field in contradiction with…

In this paper we show that electrically charged black holes in Einstein-Gauss-Bonnet gravity suffer from a superradiant instability. It is triggered by a charged scalar field that fulfills Dirichlet boundary conditions at a mirror located…

We show that the $k$-self-similar naked singularity solutions of the spherically symmetric Einstein--Scalar field system are unstable to black hole formation under perturbations that are totally supported in the interior region, in all…

We consider slowly rotating, stationary, axisymmetric black holes in the infrared limit of Horava-Lifshitz gravity. We show that such solutions do not exist, provided that they are regular everywhere apart from the central singularity. This…

We establish a no inner-horizon theorem for black holes with charged scalar hairs. Considering a general gravitational theory with a charged scalar field, we prove that there exists no inner Cauchy horizon for both spherical and planar…

By allowing the light cones to tip over on hypersurfaces according to the conservation laws of an one-kink in static, Schwarzschild and five-dimensional black hole metrics, we show that in the quantum regime there also exist instantons…

Einstein's theory of gravity admits a low energy effective quantum field description from which predictions beyond classical general relativity can be drawn. As gravitational wave detectors improve, one may ask whether non-classical…

The essential singularity in Einstein's gravity can be avoidable if the preconditions of Penrose's theorem can be bypassed, i.e., if the strong energy condition is broken in the vicinity of a black hole center. The singularity mentioned…

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…

Recently it was shown that essentially all regular black hole models constructed so far can be obtained as solutions of vacuum gravity equations, upon considering an infinite series of quasi-topological higher curvature corrections. Here we…

Classical black holes shield us from the singularities that inevitably appear in general relativity. Being singularity regularization one of the main landmarks for a successful theory of quantum gravity, quantum black holes are not obliged…

We discuss photon rings around as well as shadows of Kerr black holes immersed in a swirling spacetime (KBHSU). We find that the spin-spin interaction between the angular momentum of the black hole and the swirling of the background leads…

Viable alternatives to astrophysical black holes include hyper-compact objects without horizon, such as gravastars, boson stars, wormholes and superspinars. The authors have recently shown that typical rapidly-spinning gravastars and boson…

The lack of rotating black hole models, which are typically found in nature, in loop quantum gravity (LQG) substantially hinders the progress of testing LQG from observations. Starting with a non-rotating LQG black hole as a seed metric, we…