2023/07/08 by Stefanos Aretakis, Gaurav Khanna, Aretakis, Stefanos +3
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) #Mathematical Physics (math-ph) #Pulsars and Gravitational Waves Research
paper · pdf · doi:10.48550/arxiv.2307.03963
openalex publication_date 2023/07/08 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We consider scalar perturbations of the Reissner--Nordström family and the Kerr family. We derive a characteristic expression of the radiation field, at any given unit solid angle of future null infinity, and numerically show that its amplitude gets excited only in the extremal case. Our work, therefore, identifies an observational signature for extremal black holes. Moreover, we show that the source of the excitation is the extremal horizon instability and its magnitude is exactly equal to the conserved horizon charge.