Related papers: Static black holes in equilibrium with matter: non…
We study equilibrium conditions between a static, spherically symmetric black hole and classical matter in terms of the radial pressure to density ratio p_r/\rho = w(u), where u is the radial coordinate. It is shown that such an equilibrium…
We study the conditions of a possible static equilibrium between spherically symmetric, electrically charged or neutral black holes and ambient matter. The following kinds of matter are considered: (1) neutral and charged matter with a…
We study a spherically symmetric spacetime made of anisotropic fluid of which radial equation of state is given by $p_1 = -\rho$. This provides analytic solutions and a good opportunity to study the static configuration of black hole plus…
We consider spherically symmetric static black hole configurations that obey the vacuum equation of state: $p_{r}=-\rho $, where $p_{r}$ is the radial pressure, $\rho $ being energy density. We find in a closed form the metric for an…
We analyze the steady radial accretion of matter into a nonrotating black hole. Neglecting the self-gravity of the accreting matter, we consider a rather general class of static, spherically symmetric and asymptotically flat background…
For arbitrary static space-times, it is shown that an equilibrium between a Killing horizon and matter is only possible for some discrete values of the parameter $w = p_1/\rho$, where $\rho$ is the density and $p_1$ is pressure in the…
An anisotropic fluid with a negative radial pressure $p = - \rho$ is supposed to exist near the horizon of a Schwarzschild black hole. The constant energy density $\rho$ depends only on the black hole mass. The radial acceleration of the…
The nature of Dark Matter (DM) remains mysterious despite the substantial evidence from astrophysical and cosmological observations. While the majority of DM in our universe is non-relativistic, collisionless and its equation of state (EoS)…
We present a static, isotropic fluid solution around a black hole and its effects on the field equations and the horizon. We offer the solutions, their descriptions and we comment on their shortcomings. We derive from the proposed metric…
We study the property of matter in equilibrium with a static, spherically symmetric black hole in D-dimensional spacetime. It requires this kind of matter has an equation of state (\omega\equiv p_r/\rho=-1/(1+2kn), k,n\in \mathbb{N}), which…
In this work we model galactic halos describing the dark matter as a non zero pressure fluid and derive, not impose, a dark matter equation of state by using observational data of the rotation curves of galaxies. In order to reach…
Static spherically symmetric black holes and particle like solutions with self interacting minimally coupled scalar field {\phi} are analyzed. They are asymptotically flat or anti-de Sitter (AdS). We express them in terms of a single…
We investigate the motion of a massive particle around a spherically symmetric black hole surrounded by a stationary and radial inflow of perfect fluid. The background spacetime is modelled as a spherically symmetric solution to the…
We consider a model that charged static spherically-symmetric black hole is surrounded by dark fluid with nonlinear equation of state $p_d=-B/\rho_d$. We find that the energy density of the dark fluid can be characterized by two parameters.…
We study spherically symmetric geometries made of anisotropic perfect fluid based on general relativity. The purpose of the work is to find and classify black hole solutions in closed spacetime. In a general setting, we find that a static…
A model is proposed for the interior of a neutral non-rotating black hole. It consists of an ideal fluid with density $\r$ and a negative pressure $p$, obeying an equation of state $p=-\xi\r$. In order to have a solution, $\xi$ must lie in…
We study the spherically symmetric collapse of a fluid with non-vanishing radial pressure in higher dimensional space-time. We obtain the general exact solution in the closed form for the equation of state ($P_r = \gamma \rho$) which leads…
In this paper, we investigate a generalization of Kiselev black holes by introducing a varying equation of state parameter for the anisotropic fluid surrounding the black hole. We extend this model by allowing $w$ in the expression…
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…
In this work, a four-dimensional cylindrical symmetric and non-static or static space-times in the backgrounds of anti-de Sitter (AdS) space with perfect stiff fluid, anisotropic fluid and electromagnetic field as the stress-energy tensor,…