http://arxiv.org/abs/1904.00271
We investigate the spherical photon orbits in near-extremal Kerr spacetimes. We show that the spherical photon orbits with impact parameters in a finite range converge on the event horizon. Furthermore, we demonstrate that the Weyl curvature near the horizon does not generate the shear of a congruence of such light rays. Due to this property, a series of images produced by the light orbiting around a near-extremal Kerr black hole several times can be observable.
T. Igata, H. Ishihara and Y. Yasunishi
Tue, 2 Apr 19
6/90
Comments: 11 pages, 3 figures