Year: 2026
Type: preprint
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.
Source: arXiv (Cornell University)
Institutions: University of Copenhagen, Instituto Superior Técnico
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
Awards: Centro de Análise Matemática, Geometria e Sistemas Dinâmicos, G1789019856, G2536870102, G296744003, Centro de Análise Matemática, Geometria e Sistemas Dinâmicos, G3492272913, G4533005575, Gravitational Universe: Challenges and Opportunities, G4984070208, G5053941128, G5487836664, G5759873967, G6645931917
OpenAlex ID: W7212324906