Strong gravitational lensing by a rotating non-Kerr compact object

Дата и время публикации : 2012-04-11T14:54:44Z

Авторы публикации и институты :
Songbai Chen
Jiliang Jing

Ссылка на журнал-издание: Phys. Rev. D 85, 124029 (2012)
Коментарии к cтатье: 16 pages, 10 figures. The corrected version to be appeared in Phys. Rev. D
Первичная категория: gr-qc

Все категории : gr-qc, astro-ph.CO

Краткий обзор статьи: We study the strong gravitational lensing in the background of a rotating non-Kerr compact object with a deformed parameter $epsilon$ and an unbound rotation parameter $a$. We find that the photon sphere radius and the deflection angle depend sharply on the parameters $epsilon$ and $a$. For the case in which the black hole is more prolate than a Kerr black hole, the photon sphere exists only in the regime $epsilonleqepsilon_{max}$ for prograde photon. The upper limit $epsilon_{max}$ is a function of the rotation parameter $a$. As $epsilon>epsilon_{max}$, the deflection angle of the light ray closing very to the naked singularity is a positive finite value, which is different from those in both the usual Kerr black hole spacetime and in the rotating naked singularity described by Janis-Newman-Winicour metric. For the oblate black hole and the retrograde photon, there does not exist such a threshold value. Modelling the supermassive central object of the Galaxy as a rotating non-Kerr compact object, we estimated the numerical values of the coefficients and observables for gravitational lensing in the strong field limit.

Category: Physics