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arXiv · 2610.23486

Near-Extremal Black-Hole Formation Observed from Null Infinity

Thomas Mädler·Radouane Gannouji·Steven L. Liebling·Emanuel Gallo
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Abstract

We identify near-extremal black-hole formation directly from observables at future null infinity. Fully nonlinear evolutions of the spherically symmetric Einstein--Maxwell--charged scalar system in 3+1 dimensions form black holes with charge-to-mass ratios up to 0.993 from regular, horizon-free, superextremal initial data. Quasinormal frequencies and redshift decay independently recover the near-extremal charge-to-mass ratio. Critical mass scaling is recovered at null infinity and charge scaling at the apparent horizon. The charged scalar Newman--Penrose quantity obeys an asymptotic balance law that replaces the conservation law of the neutral theory.

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Thomas Mädler, Radouane Gannouji, Steven L. Liebling, Emanuel Gallo. 2026-10-16. Near-Extremal Black-Hole Formation Observed from Null Infinity. https://arxiv.org/abs/2610.23486

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