Polarized Image of a Rotating Black Hole in Scalar–Tensor–Vector–Gravity Theory

Abstract

The polarized images of a synchrotron emitting ring are studied in the spacetime of a rotating black hole in the scalar–tensor–vector–gravity (STVG) theory. The black hole owns an additional dimensionless modified gravity (MOG) parameter described as its deviation from a Kerr black hole. The effects of the MOG parameter on the observed polarization vector and Strokes Q − U loops depend heavily on the spin parameter, the magnetic field configuration, the fluid velocity, and the observation inclination angle. For the fixed MOG parameter, the changes of the polarization vector in the image plane are similar to those in the Kerr black hole case. The comparison of the polarization images between the Kerr−MOG black hole and M87* implies that there remains some possibility for the STVG−MOG theory.