We provide new very simple and compact expressions for the efficient calculation of gravitational lens optical scalars for Kerr space-time, which are exact along any null geodesic. These new results are obtained recurring ...

In this paper, we study massless braneworld black holes as gravitational lenses. We find the weak and the strong deflection limits for the deflection angle, from which we calculate the positions and magnifications of the ...

Gravitationally lensed quasars are valuable, but extremely rare, probes of observational cosmology and extragalactic astrophysics. Progress in these fields has been limited just by the paucity of systems with good ancillary ...

We propose that some of the high-latitude unidentified EGRET -ray sources could be the result of gravitational lensing amplification of the innermost regions of distant, faint, active galactic nuclei. These objects have ...