Radiating Kerr–Newman black hole in f(R) gravity

Abstract

We derive an exact radiating Kerr-Newman like black hole solution, with constant curvature R = R0 imposed, to metric f (R) gravity via complex transformations suggested by Newman-Janis. This generates a geometry which is precisely that of radiating Kerr-Newman-de Sitter / anti-de Sitter with the f (R) gravity contributing an R0 cosmological-like term. The structure of three horizonlike surfaces, viz. timelike limit surface, apparent horizon and event horizon, are determined. We demonstrate the existence of an additional cosmological horizon, in f (R) gravity model, apart from the regular black hole horizons that exist in the analogous general relativity case. In particular, the known stationary Kerr-Newman black hole solutions of f (R) gravity and general relativity are retrieved. We find that the timelike limit surface becomes less prolate with R0 thereby affecting the shape of the corresponding ergosphere.

Applicability of the Newman-Janis algorithm to black hole solutions of modified gravity theories

“…In deriving the above equation, we used the nonrotated scalar field of Eq. (30), which obviously also matches that of [20] in the slow-rotation limit. Terms of O(a/M ) in the scalar field cannot make E tφ = 0, as this quantity is already of O(a/M ) and the difference between the solution found in [20] and the NJA rotated of Eq.…”

“…One can verify this by using an NJA rotated version of Eq. (30). The three methods to apply the complexification of the NJA described at the end of Sec.…”

Holographic thermalization in AdS-Gauss–Bonnet gravity for small entangled regions

“…In a Vaidya form, f (z) from (2.8) has a dependence on a new time coordinate, υ, via the mass function and would be changed like (see for instance [26,27,28]):…”

Blackhole in nonlocal gravity: comparing metric from Newmann–Janis algorithm with slowly rotating solution

“…Lately, Newmann-Janis method has been used comfortably as a way to derive the Kerr metric in different modified gravity theories [30][31][32][33][34]. But, it should be done with caution since the metric generated from the NJ method may not be the solution of the field equations of a particular theory.…”