Polarized image of a rotating black hole in Scalar-Tensor-Vector-Gravity theory

TL;DR

This paper investigates the polarized images of a rotating black hole within Scalar-Tensor-Vector-Gravity (STVG) theory, highlighting how the MOG parameter influences polarization features and comparing results with Kerr black holes and M87* observations.

Contribution

It introduces the effects of the MOG parameter on polarized images of rotating black holes in STVG theory, extending previous Kerr black hole models.

Findings

MOG parameter affects polarization vectors and $Q-U$ loops depending on spin and viewing angle.

Polarization changes in STVG black holes are similar to Kerr black holes for fixed MOG parameter.

Comparison suggests STVG-MOG theory remains plausible based on polarization image analysis.

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 MOG parameter described its deviation from 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 Kerr-MOG black hole and M87* implies that there remains some possibility for the STVG-MOG theory.