http://arxiv.org/abs/1402.6823

The gravitational lensing effects in the weak gravitational field by exotic lenses have been investigated intensively to find non-luminous exotic objects. Gravitational lenses in a strong gravitational field also are important since they are one of tests for general relativity, black holes and exotic objects. It is known that the light rays which pass just outside the photon sphere make faint images in the Schwarzschild spacetime and in wormhole spacetimes. This is the same in the Tangherlini spacetime. In this paper, we investigate the gravitational lensing effects in the Tangherlini spacetime in the weak gravitational field and the strong field limit. The gravitational lens model in the Tangherlini spacetime would work as a wide-range toy model for exotic lens models with the photon sphere since it is an exact solution of the Einstein equation in every dimension. We study the deflection angle of the light and the magnifications of images in the weak approximation and in the strong field limit. We derive the divergent part of the deflection angle in all dimensions and the regular part of the deflection angle in 4, 5 and 7 dimensions in the strong field limit, the deflection angle in all dimensions under the weak gravitational approximation and the relation between the size of the Einstein ring and the ones of the rings in the strong gravitational field. We also show that the images in the strong gravitational field are always fainter than the images in the weak gravitational field. We conclude that the images in the strong gravitational field have little effect on the total light curve and that the characteristic demagnification of the light curve will appear after considering the images in the strong gravitational field in higher dimensions. The gravitational lensing in the strong field limit in higher dimension would be related to the nature of the higher dimensional black hole.

Read this paper on arXiv…

N. Tsukamoto, T. Kitamura, K. Nakajima, et. al.
Fri, 28 Feb 14
54/54