OPTICAL PHENOMENA IN THE FIELD OF BRANEWORLD KERR BLACK HOLES

We study the influence of the tidal charge parameter of the braneworld models on some optical phenomena in rotating black hole space-times. The escape photon cones are determined for special families of locally nonrotating, circular geodetical and radially free-falling observers. The silhouette of a rotating black hole, the shape of an equatorial thin accretion disk and the time delay effect for direct and indirect images of a radiating hot spot orbiting the black hole are given and classified in terms of the black hole rotational and tidal parameters. It is shown that increase of the negatively valued tidal parameter, with the rotational parameter fixed, generally strengthens the relativistic effects and suppresses the rotation-induced asymmetries in the optical phenomena.