Gravitational Lensing by Black Holes in Einsteinian Cubic Gravity

TL;DR

This paper explores how Einsteinian Cubic Gravity predicts different gravitational lensing effects by black holes compared to general relativity, indicating potential for observational testing of alternative gravity theories.

Contribution

It introduces a method to compute the metric in ECG and demonstrates significant deviations in lensing observables from GR, highlighting testability.

Findings

Time delays and image positions differ by milliarcseconds from GR

Deviations are large enough for observational detection

Method uses continued fraction approach for metric calculation

Abstract

We investigate the predictions of Einsteinian Cubic Gravity (ECG) for the lensing effects due to supermassive black holes at the center of Milky Way and other galaxies. Working in the context of spherical symmetry, we obtain the metric function from a continued fraction method and find that both time delays and the angular positions of images considerably deviate from general relativity, as large as milliarcseconds. This suggests that observational tests of ECG are indeed feasible.