Shapes of rotating nonsingular black hole shadows
Abstract
It is believed that curvature singularities are a creation of general relativity and, hence, in the absence of a quantum gravity, models of nonsingular black holes have received significant attention. We study the shadow (apparent shape), an optical appearance because of its strong gravitational field, cast by a nonsingular black hole which is characterized by three parameters, i.e., mass (M ), spin (a ), and a deviation parameter (k ). The nonsingular black hole under consideration is a generalization of the Kerr black hole that can be recognized asymptotically (r ≫k ,k >0 ) explicitly as the KerrNewman black hole, and in the limit k →0 as the Kerr black hole. It turns out that the shadow of a nonsingular black hole is a dark zone covered by a deformed circle. Interestingly, it is seen that the shadow of a black hole is affected due to the parameter k . Indeed, for a given a , the size of a shadow reduces as the parameter k increases, and the shadow becomes more distorted as we increase the value of the parameter k when compared with the analogous Kerr black hole shadow. We also investigate, in detail, how the ergoregion of a black hole is changed due to the deviation parameter k .
 Publication:

Physical Review D
 Pub Date:
 July 2016
 DOI:
 10.1103/PhysRevD.94.024054
 arXiv:
 arXiv:1603.06382
 Bibcode:
 2016PhRvD..94b4054A
 Keywords:

 General Relativity and Quantum Cosmology
 EPrint:
 11 pages, 11 figures, Published version