Quasinormal modes and gray-body factors of regular black holes in asymptotically safe gravity

TL;DR

This paper analyzes quasinormal modes, shadows, and grey-body factors of regular black holes in asymptotically safe gravity, revealing unique overtone behaviors and consistency with observational data.

Contribution

It provides detailed QNM spectra, shadow analysis aligned with EHT observations, and bounds on grey-body factors for black holes in this gravity framework.

Findings

Fundamental QNM frequencies and overtones identified

Black hole shadows match EHT observations

Explicit lower bounds for grey-body factors derived

Abstract

Recently, Bonanno et al. (2024) presented an explicit metric describing the exterior of a collapsing dust ball within the framework of asymptotically safe gravity. Based on this metric, we investigate in detail the properties of the quasinormal mode (QNM) spectra for test massless scalar, vector, and Dirac fields. We find accurate values for the fundamental QNM frequency and the first overtones, demonstrating the appearance of a peculiar spiral-like behavior of the overtones compared to the fundamental modes. Additionally, we study black hole shadows and show that they align with EHT observations. Finally, we study the grey-body factors and provide explicit lower bound estimates.