Rotating regular black holes

Abstract

The formation of spacetime singularities is a quite common phenomenon in General Relativity and it is regulated by specific theorems. It is widely believed that spacetime singularities do not exist in Nature, but that they represent a limitation of the classical theory. While we do not yet have any solid theory of quantum gravity, toy models of black hole solutions without singularities have been proposed. So far, there are only non-rotating regular black holes in the literature. These metrics can be hardly tested by astrophysical observations, as the black hole spin plays a fundamental role in any astrophysical process. In this letter, we apply the Newman-Janis algorithm to the Hayward and to the Bardeen black hole metrics. In both cases, we obtain a family of rotating solutions. Every solution corresponds to a different matter configuration. Each family has one solution with special properties, which can be written in Kerr-like form in Boyer-Lindquist coordinates. These special solutions are of Petrov type D, they are singularity free, but they violate the weak energy condition for a non-vanishing spin and their curvature invariants have different values at r = 0 depending on the way one approaches the origin. We propose a natural prescription to have rotating solutions with a minimal violation of the weak energy condition and without the questionable property of the curvature invariants at the origin.

Generic rotating regular black holes in general relativity coupled to nonlinear electrodynamics

“…All the subtleties of the nonlinear effects were discussed in [15][16][17][18]. Rotating regular black hole solutions have been introduced in [19][20][21][22][23][24]. Similarly to the Kerr or Reissner-Nordström solutions of the standard general relativity that describe both black holes and naked singularities, the regular solutions describe both the black hole and no-horizon spacetimes demonstrating strong gravity effects [25][26][27][28][29][30][31][32].…”

Upper Limit of Radiation from Coalescence of Rotating Hayward Black Holes

“…[29,30]. Given a Hayward black hole of mass M and angular momentum J = Ma, the metric is in Boyer-Lindquist coordinates…”

“…Based the weak cosmic censorship conjecture, the singularity should be hidden by the event horizon of the black hole, but the Hayward black hole has no singularity within the horizon. Using the Newman-Janis transformation [30], the rotating Hayward black hole is obtained. The metric of the Hayward black hole is also found in the gravity theory coupled with non-linear electrodynamics [31].…”

Note on regular black holes in a brane world

“…[6], it is formed by a nonlinear electrodynamic field. RBH solutions with axial symmetry have been constructed as well (see the recent works [7][8][9][10][11][12][13]). Contrary to the spherical case, we have shown that axisymmetric RBHs always violate the WEC [10].…”