Related papers: Apparent horizons in cosmologically-embedded black…
Motivations for the existence of a fundamental preferred frame range from pure phenomenology to attempts to solve the non-renormalizability of quantum gravity, the problem of time (and scale), and the cosmological constant problem(s). In…
Working in a semi-classical setting, we consider solutions of the Einstein equations that exhibit light trapping in finite time according to distant observers. In spherical symmetry, we construct near-horizon quantities from the assumption…
The existence of black holes is a central prediction of general relativity and thus serves as a basic consistency test for modified theories of gravity. In spherical symmetry, only two classes of dynamic solutions are compatible with the…
Local condition that imply the no-hair property of black holes are completed. The conditions take the form of constraints on the geometry of the 2-dimensional crossover surface of black hole horizon. They imply also the axial symmetry…
The `runaway solutions' of the Lorentz-Dirac equation of a charged particle interacting with its own field in classical electrodynamics are well-known. This type of self accelerated phenomena also exists in the solutions of the…
We study the extent of quantum gravitational effects in the internal region of non-singular, Hayward-like solutions of Einstein's field equations according to the formalism known as Horizon Quantum Mechanics. We grant a microscopic…
Mass inflation is a phenomenon happened in the vicinity of inner horizon in two-horizon spacetime. It is shown that the mass of initially small perturbations will grow exponentially as they approach the inner horizon. This implies that…
Event horizons are a defining feature of black holes. Consequently, there have been many efforts to probe their existence in astrophysical black hole candidates, spanning ten orders of magnitude in mass. Nevertheless, horizons remain an…
We argue that a genuine image of the black hole viewed by a distant observer is not its shadow, but a more compact event horizon image probed by the luminous matter plunging into black hole. The external border of the black hole shadow is…
String theory and ``quantum geometry'' have recently offered independent statistical mechanical explanations of black hole thermodynamics. But these successes raise a new problem: why should models with such different microscopic degrees of…
Trapped regions bounded by horizons are the defining features of black holes. However, formation of a singularity-free apparent horizon in finite time of a distant observer is consistent only with special states of geometry and matter in…
We consider stationary extreme black hole solutions to the Einstein-Yang-Mills equations in four dimensions, allowing for a negative cosmological constant. We prove that any axisymmetric black hole of this kind possesses a near-horizon…
A new solution of the Einstein equations for the point mass immersed in the de Sitter Universe is presented. The properties of the metric are very different from both the Schwarzschild black hole and the de Sitter Universe: it is everywhere…
The known static electro-vacuum black holes in a globally AdS$_4$ background have an event horizon which is geometrically a round sphere. In this work we argue that the situation is different in models with matter fields possessing an…
We investigate the possibility of having hairs on the cosmological horizon. The cosmological horizon shares similar properties of black hole horizons in the aspect of having hairs on the horizons. For those theories admitting haired black…
Recently, new exploratory channels have opened up for the physics of highly compact objects, such as gravitational waves and black hole shadows. Moreover, more precise analysis and observations are now possible in the physics of accretion…
We summarize recent results on the properties of near-horizon metrics in different spherically symmetric space-times, including Kantowski-Sachs cosmological models whose evolution begins with a horizon (the so-called Null Big Bang) and…
In this paper we aim to provide new examples of the application and the generality of the membrane paradigm. The membrane paradigm is a formalism for studying the event horizon of black holes. After analyzing it with some technical details…
There has recently been some considerable interest expressed in a highly speculative model of black hole evolution -- allegedly by a postulated direct coupling between black holes and cosmological expansion independently of accretion or…
The spherical symmetry Black holes are considered in expanding background. The singularity line and the marginally trapped tube surface behavior are discussed. In particular, we address the conditions of whether a dynamical horizon forms…