Gravitational Lensing Effect from The Revised Deser-Woodard Nonlocal Gravity

TL;DR

This paper explores how a revised nonlocal gravity model affects gravitational lensing around black holes, revealing unique weak and strong field signatures that could help differentiate it from other theories.

Contribution

It provides the first detailed analysis of gravitational lensing effects in the revised Deser-Woodard nonlocal gravity model, including both weak and strong field regimes.

Findings

Weak field deflection angle has a leading-order correction due to nonlocality.

Strong field lensing corrections depend linearly on the coupling parameter and are exponentially suppressed by another parameter.

Lensing behavior exhibits scale-invariance similar to General Relativity and conformal gravity.

Abstract

We investigate the gravitational lensing effects of a static spherically symmetric black hole (BH) within the framework of the revised Deser-Woodard (D-W) nonlocal gravity. By analyzing the deflection angle in both the weak and strong field limits, we derive several distinguishing features of the model. In the weak field limit, we report a leading-order correction to the deflection angle directly attributed to the non-local nature of the theory. In the strong field limit, we find that the lensing corrections are almost linearly dependent on the coupling parameter $\zeta$ while being exponentially suppressed by the exponent parameter $n$. Furthermore, the gravitational lensing effect in the revised D-W model at a given time shares similar scale-invariant behavior to General Relativity and conformal gravity, offering a potential pathway to distinguish it from other alternatives using astronomical observations.