5–6 oct. 2026
Fuseau horaire Europe/Paris

Logarithmic divergence of the fluxes at the light ring for unstable circular orbits

5 oct. 2026, 16:20
12m

Orateur

David Trestini (University of Southampton)

Description

At first self-force order, we consider the energy flux emitted by a particle orbiting a Schwarzschild black hole on an unstable circular orbit just outside the light ring. Both the flux to infinity and the flux down the horizon diverge as the orbit approaches the light ring, growing like the inverse of the distance to it, times a logarithm of that distance. This logarithmic divergence arises from an infinite sum over $m$-modes and is therefore out of reach of numerical methods. We determine the coefficient of the logarithmic divergence analytically using WKB methods; it is universal, i.e., the same for both fluxes. We then obtain the remaining coefficients (one for each flux) by a combination of numerical and analytical methods. We expect these results to be useful, e.g., to inform resummations and study ultrarelativistic scattering. They highlight the potential of analytical methods to address problems in self-force in regions of parameter space where traditional numerical methods fail.

Which working group does your abstract concern? Formes d'ondes / Waveforms

Auteur

David Trestini (University of Southampton)

Co-auteur

Dr Riccardo Gonzo

Documents de présentation

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