Regularized stable Kerr black hole: cosmic censorships, shadow and quasi-normal modes

• Published in: The European physical journal. C, Particles and fields Vol. 83; no. 1; pp. 91 - 10
• Main Authors: Ghosh, Rajes, Rahman, Mostafizur, Mishra, Akash K.
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.01.2023; Springer; Springer Nature B.V; SpringerOpen
• Subjects: Analysis; Astronomy; Astrophysics and Cosmology; Black holes; Censorship; Consistency; Elementary Particles; Event horizon; Gravitation theory; Gravity; Hadrons; Heavy Ions; Inflation (Finance); Mathematical models; Measurement Science and Instrumentation; Nuclear Energy; Nuclear Physics; Parameters; Perturbation; Physics; Physics and Astronomy; Quantum Field Theories; Quantum Field Theory; Quantum theory; Regular Article - Theoretical Physics; Relativity; Shadows; String Theory; Theory of relativity
• ISSN: 1434-6052; 1434-6044; 1434-6052
• DOI: 10.1140/epjc/s10052-023-11252-0

Black hole solutions in general relativity come with pathologies such as singularity and mass inflation instability, which are believed to be cured by a yet-to-be-found quantum theory of gravity. Without such consistent description, one may model theory-agnostic phenomenological black holes that bypass the aforesaid issues. These so-called regular black holes are extensively studied in the literature using parameterized modifications over the black hole solutions of general relativity. However, since there exist several ways to model such black holes, it is important to study the consistency and viability of these solutions from both theoretical and observational perspectives. In this work, we consider a recently proposed model of regularized stable rotating black holes having two extra parameters in addition to the mass and spin of a Kerr solution. We start by computing their quasi-normal modes under scalar perturbation and investigate the impact of those additional parameters on black hole stability. In the second part, we study shadows of the central compact objects in M 87 ∗ and S g r A ∗ modelled by these regularized black holes and obtain stringent bounds on the parameter space requiring consistency with Event Horizon Telescope observations.