Absorption, Scattering, Geodesics, Shadows and Lensing Phenomena of Black Holes in Effective Quantum Gravity

TL;DR

This paper explores the observable signatures of black holes in an effective quantum gravity model, analyzing light behavior, shadows, absorption, and lensing phenomena, and comparing theoretical predictions with observational data.

Contribution

It provides a comprehensive analysis of black hole shadows, absorption cross sections, and gravitational lensing within a novel quantum gravity framework, including bounds based on EHT data.

Findings

Estimated lower bounds for shadow radius from EHT data.

Derived radial wave equation for scalar perturbations.

Analyzed gravitational lensing in weak and strong deflection regimes.

Abstract

In this work, we investigate the signatures of black holes within an effective quantum gravity framework recently proposed in the literature [1] . We begin by outlining the general setup, highlighting the two distinct models under consideration. This includes a discussion of their general properties, interpretations, and the structure of the event and inner horizons. We then examine the behavior of light in this context, analyzing geodesics, the photon sphere, and shadow formation. To validate our results, we estimate lower bounds for the shadow radius based on observational data from the Event Horizon Telescope (EHT). Subsequently, we derive the partial radial wave equation for scalar perturbations, enabling us to study the absorption cross section in both low and high frequency regimes. Additionally, we evaluate the greybody factors and provide bounds for both bosonic and fermionic fields. Finally, we present a detailed analysis of gravitational lensing in both the weak and strong deflection limits. For the weak deflection regime, the Gauss Bonnet theorem is employed, while for the strong deflection limit, the Tsukamoto approach is utilized.