The Shadows of Regular Black Holes with Asymptotic Minkowski Cores

Abstract

We investigate the shadows cast by a sort of new regular black hole which are characterized by an asymptotic Minkowski core and sub-Planckian curvature. First, we extend the metric with spherical symmetry to the one of rotating Kerr-like black holes and derive the null geodesics with a circular orbit near the horizon of the black hole. Then, we plot the shadows of black holes with different values for the deviation parameter. It is found that the size of the shadow shrinks with the increase in the deviation parameter, while the shape of the shadow becomes more deformed. In particular, by comparing with the shadow a Bardeen black hole and Hayward black hole with the same parameter values, we find that, in general, the shadows of black holes with Minkowski cores have larger deformations than those with de Sitter cores, which potentially provides a strategy to distinguish these two sorts of regular black holes with different cores by astronomical observation in the future.

Gravito-electromagnetic perturbations and QNMs of regular black holes

“…In this work, we focus on the case of spherical regular BHs. It is natural to extend the current study to rotating case which will be more realistic from astrophysical viewpoint [83][84][85][86][87][88]. We would like to leave this for further investigations.…”

Horizon-scale tests of gravity theories and fundamental physics from the Event Horizon Telescope image of Sagittarius A ∗

“…The GCSV BH was introduced in [351][352][353], including work by one of us, as toy model of a regular BH in the sense of Bardeen, where the core is asymptotically Minkowski rather than de Sitter 33 : stated differently, the associated energy density and pressure asymptote to zero rather than to a final value determined by the effective cosmological constant of the de Sitter case (see also [131,[354][355][356][357][358][359][360][361][362]). While the GCSV BH is introduced in a purely phenomenological way, Simpson and Visser (SV) argued in [353] that this space-time is mathematically interesting due to its tractability (the curvature tensors and invariants take forms which are much simpler than those of the Bardeen, Hayward, and Frolov BHs), and physically interesting because of its non-standard asymptotically Minkowski core.…”

Regular black holes with sub-Planckian curvature

“…Instead, the Kretschmann scalar curvature is always zero at the center and reaches its maximum value at a point between the center and the horizon. This distinction may result in observable effects in the future and has been theoretically investigated in [32,43]. It is found that the shadows of black holes with Minkowski cores have larger deformations than those with de-Sitter cores.…”