For black hole coronae in particular, relativistic radiative reconnection is thought to power the background X-ray emission through Inverse Compton scattering on seed photons by the bulk flow. We model this process both with kinetic theory — describing the effects of energy-momentum loss due to scattering as a radiative drag force, and with fluid theory — describing the same effect as a sink term in the energy-momentum conservation equations. I will derive both kinetic and fluid theory cooling terms and their scaling, and show for the first time that the fluid theory analytics recovers kinetic radiative reconnection in charge-starved X-points. Such a mapping finally provides a physically informed subgrid model for relativistic radiative reconnection in magnetohydrodynamic simulations of black hole accretion disk coronae.
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Alicia Savelli
University of Toronto
July 09, 2025
