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arXiv · 2609.10689

Wave optical imaging of an oscillating electric dipole orbiting a black hole

Filipe Nazaré·João S. Santos·Vitor Cardoso·José Natário
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Abstract

We study the electromagnetic radiation and wave-optical imaging of an oscillating electric dipole orbiting a Kerr black hole. We derive the effective 4-current associated with a pointlike oscillating electric dipole in curved spacetime, and use black hole perturbation theory to compute the resulting radiation field at future null infinity, from first principles. We then develop a wave-optical imaging framework for a moving electromagnetic source in curved spacetime. We obtain images of an orbiting electric dipole, displaying relativistic beaming, gravitational lensing, and Einstein rings. We study polarization-dependent scattering by comparing the images produced by spinning dipoles with opposite helicities, finding a displacement that roughly decreases with the inverse of the radiation frequency, as expected for a beyond-geometric-optics effect. Our results provide a first-principles benchmark for beyond-geometric-optics descriptions of electromagnetic radiation in Kerr spacetime.

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Filipe Nazaré, João S. Santos, Vitor Cardoso, José Natário. 2026-09-09. Wave optical imaging of an oscillating electric dipole orbiting a black hole. https://arxiv.org/abs/2609.10689

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