Can we distinguish whether black holes have singularities or not through echoes and light rings?

2025/05/16 by Rao, Xiao-Pin, Huang, Hyat · 2 citations
Physics and Astronomy · #Astrophysical Phenomena and Observations #Black Holes and Theoretical Physics #FOS: Physical sciences #General Relativity and Quantum Cosmology (gr-qc) #High Energy Physics - Theory (hep-th) #Pulsars and Gravitational Waves Research

paper · pdf · doi:10.48550/arxiv.2505.11073

openalex publication_date 2025/05/16 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28

Abstract

A recent work [Phys. Rev. D 111, 104040] shows that the curvature singularity of a black hole can vanish at a fine-tuned mass value, which implies that regular black holes could be special states in black hole evolution. We study the quasinormal modes (QNMs) of the Bardeen black hole and its singular counterparts under scalar and electromagnetic perturbations, employing the WKB method and time-domain analysis, respectively. The time-domain analysis results suggest that echo signals may emerge in the QNMs of singular black hole states. Furthermore, we investigate the null geodesics of these black holes. We find that a black hole with singularity may possess two light rings, whereas regular black holes consistently maintain only one light ring. Similar conclusions are also valid for the regular Hayward black hole and its singular counterparts.

Citations

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Cited by

• Dark matter production from evaporation of regular primordial black holes
• Light Rings, Accretion Disks and Shadows of Hayward Boson Stars in asymptotically AdS Spacetime

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• Observational appearance and photon rings of non-singular black holes from anisotropic fluids