Related papers: On Black Ring with a Positive Cosmological Constan…
It is believed that gravity will be explained in the framework of the existing quantum theory when one succeeds in eliminating divergencies at large momenta or small distances (although the phenomenon of gravity has been observed only at…
We consider stationary, non-extremal black holes in 11-dimensional supergravity having isometry group $\mathbb{R} \times U(1)^8$. We prove that such a black hole is uniquely specified by its angular momenta, its electric charges associated…
In this work we analyze a solution that mimics the Bardeen solution with a cosmological constant surrounded by quintessence. We show that this solution can be obtained by Einstein equations coupled with nonlinear electrodynamics. We also…
We reconsider the virial theorem in the presence of a positive cosmological constant Lambda. Assuming steady state, we derive an inequality of the form rho >= A (Lambda / 4 pi GN) for the mean density rho of the astrophysical object. With a…
A spherically symmetric charged ideal fluid solution of Einstein field equation is given in the presence of the cosmological constant and two well known example of this type of solution is presented. If the matter is confined in a region,…
In this paper, static electrically charged black hole solutions with cosmological constant are investigated in an Einstein-Hilbert theory of gravity with additional quadratic curvature terms. Beside the analytic Schwarzschild (Anti-) de…
We investigate stable central structures in multiply-connected, anti de Sitter spacetimes with spherical, planar and hyperbolic geometries. We obtain an exact solution for the pressure in terms of the radius when the density is constant. We…
An exact and analytical solution of four dimensional vacuum General Relativity representing a system of two static black holes at equilibrium is presented. The metric is completely regular outside the event horizons, both from curvature and…
Exact static, spherically symmetric solutions to the Einstein-Maxwell-scalar equations, with a dilatonic-type scalar-vector coupling, in $D$-dimensional gravity with a chain of $n$ Ricci-flat internal spaces are considered. Their properties…
Thermodynamical stability of fluid spheres is studied in the presence of a cosmological constant, both in the Newtonian limit, as well as in General Relativity. In all cases, an increase of the cosmological constant tends to stabilize the…
We study the possibility of having Black hole of spherical and ring horizon topology with five independent charges in the $U(1)^3$-model of 5D gauge supergravity. To study these possibilities we consider not only the known result obtained…
An $arctan$-electrodynamics coupled with the gravitational field is investigated. We obtain the regular black hole solution that at $r\rightarrow \infty$ gives corrections to the Reissner-Nordstr\"om solution. The corrections to Coulomb's…
In this paper we use and extend the results present in \cite{1,2,3,4} and in particular in \cite{4} to obtain a statistical description of the cosmological constant in a cosmological de Sitter universe in terms of massless excitations with…
A non-singular, static spherically symmetric solution to the nonsymmetric gravitational and electromagnetic theory field equations is derived, which depends on the four parameters m, l^2, Q and s, where m is the mass, Q is the electric…
We explore via linearized perturbation theory the Gregory-Laflamme instability of rotating black strings with equal magnitude angular momenta. Our results indicate that the Gregory-Laflamme instability persists up to extremality for all…
The Einstein-conformally coupled scalar field system is studied in the presence of a cosmological constant. We consider a massless or massive scalar field with no additional self-interaction, and spherically symmetric black hole geometries.…
Using a confining potential, we consider spherically symmetric vacuum (static black hole) solutions in a brane-world scenario. Working with a constant curvature bulk, two interesting cases/solutions are studied. A Schwarzschild-de Sitter…
Static black holes in the conformal anomaly-sourced semi-classical General Relativity in four dimensions were extended to rotating, stationary solutions, recently. These quantum-corrected black holes show different features compared to the…
We study the optical appearance of Schwarzschild-de Sitter and Reissner-Nordstr\"{o}m-de Sitter black holes viewed by distant observers inside cosmological horizons. Unlike their asymptotically flat counterparts, due to the positive…
The cosmological constant problem is studied in a two component cosmological model. The universe contains a cosmological constant of an arbitrary size and sign and an additional component with an inhomogeneous equation of state. It is shown…