The eye of the storm: A regular Kerr black hole

Abstract

We present a highly tractable non-singular modification of the Kerr geometry, dubbed the "eye of the storm" -a rotating regular black hole with an asymptotically Minkowski core. This is achieved by "exponentially suppressing" the mass parameter in the Kerr spacetime: m → m e −ℓ/r . The single parameter ℓ quantifies the deviation from the usual Kerr spacetime. Some of the classical energy conditions are globally satisfied, whilst certain choices for ℓ force any energy-condition-violating physics into the deep core. The geometry possesses the full "Killing tower" of principal tensor, Killing-Yano tensor, and nontrivial Killing tensor, with associated Carter constant; hence the Hamilton-Jacobi equations are separable, and the geodesics integrable. The Klein-Gordon equation is also separable on this candidate spacetime. The tightly controlled deviation from Kerr renders the physics extraordinarily tractable when compared with analogous results in the current literature. This spacetime will be amenable to straightforward extraction of astrophysical observables falsifiable/ verifiable by the experimental community.

Field sources for Simpson-Visser space-times

“…The sources of black bounce space-times proposed in [48] can also be easily calculated. A task of interest for a future study can be to find a source for SV-like geometries with rotation [49][50][51]66].…”

Constant-$r$ geodesics in the Painleve-Gullstrand form of Lense-Thirring spacetime

“…From a wider perspective, these considerations can be viewed as an element of the study of modified black holes -alternative black holes to the standard Schwarzschild-Kerr family that are nevertheless carefully formulated so as to pass the most obvious observational tests, and so provide useful templates for driving observational astrophysics [62][63][64][65][66][67][68][69][70][71][72][73][74][75][76][77].…”

Light ring images of double photon spheres in black hole and wormhole space-times

“…The second half would simply require to find a single unmistakable observation of an alternative compact object disguised as a Kerr black hole, i.e., a black hole mimicker [12]. A plethora of such objects has been proposed in the literature, including non-Kerr black holes [13], boson stars [14], gravastars [15], fuzzballs [16], wormholes [17], and so on. In order to reveal the nature of black hole candidates, the newly-born field of multimessenger astronomy uses its full weaponry: electromagnetic radiation, gravitational waves, and neutrinos [18,19].…”