Gravitational lensing by f(R, T) gravity

A solution for f(R, T) gravity of the type f(R, T) = f(1)(R) + f(2)(T) for specific f(2)(T) functions is derived. It is shown that a slight modification to the Schwarzschild metric can be found for f(2)(T) = alpha T-n + beta, where n > 0, beta << 1 and a is some constant. The effects of f(R, T) gravity on gravitational lensing are calculated and the differences with general relativity are compared. Furthermore, it is shown that modified gravity can give a considerable contribution to gravitational lensing.