Gravitational lensing in the strong field limit by modified gravity

An investigation of the strong gravitational lensing in specific model of modified gravity is presented. It is shown that a slight modification to the general relativistic metric near the neighborhood of complete capture can be obtained. The formulae for the position of the critical curves, relativistic images and their magnification in the new metric are calculated and the differences with general relativity are compared. Furthermore, the radius of stable orbits is derived and the critical impact parameter is calculated. Finally, it is shown that in the strong field limit this solution may give a considerable contribution to gravitational lensing.