Gravitational Lensing by a Dark Compact Object in Modified Gravity and Observational Constraints from Einstein Rings

TL;DR

This paper investigates gravitational lensing effects caused by dark compact objects within a Modified Gravity framework, analyzing deflection angles and observational signatures, and comparing them with standard Schwarzschild black holes for real galactic lenses.

Contribution

It provides new calculations of weak and strong deflection angles in MOG and compares observational lensing features of MOG black holes with Schwarzschild black holes.

Findings

MOG predicts distinct lensing coefficients compared to Schwarzschild black holes.

Weak field lensing signatures can differentiate MOG from general relativity.

Strong field lensing parameters for M87* and Sgr A* are characterized within MOG.

Abstract

In this manuscript, we provide a comprehensive study of gravitational lensing by dark compact objects predicted by a Modified Gravity (MOG) based on the Scalar-Vector-Tensor action, and the aim is to analyze new insights into the nature of gravitational interactions. We compute weak and strong deflection angles for the specified static, spherically symmetric MOG spacetime. Additionally, we dedicate a section to explore observational implications in the weak field limit. By employing a supermassive galactic black hole as a gravitational lens, we compare various parameters in MOG with those of the Schwarzschild black hole as lens in strong-field scenarios. Specifically, we model the black holes M87${^*}$ and Sgr A${^*}$ as lenses within the MOG framework, calculating the corresponding lensing coefficients and distortion parameters in the weak field regime.