Publications by authors named "Kyle Parfrey"

Article Synopsis
  • The study investigates how collisionless plasma accumulates around a rotating black hole using advanced simulations, comparing results from particle-in-cell and magnetohydrodynamic methods.
  • Key differences were found, including more efficient magnetic reconnection and the rapid acceleration of nonthermal particles in the particle-in-cell simulations, as well as significant deviations from thermal equilibrium in the plasma.
  • The findings have important implications for understanding and modeling observations of black holes like Sgr A* and M87, particularly regarding the behaviors analyzed by the GRAVITY and Event Horizon Telescope collaborations.
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Accreting supermassive black holes can now be observed at the event-horizon scale at millimeter wavelengths. Current predictions for the image rely on hypotheses (fluid modeling, thermal electrons) which might not always hold in the vicinity of the black hole, so that a full kinetic treatment is in order. In this Letter, we describe the first 3D global general-relativistic particle-in-cell simulation of a black-hole magnetosphere.

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Black holes are known to launch powerful relativistic jets and emit highly variable gamma radiation. How these jets are loaded with plasma remains poorly understood. Spark gaps are thought to drive particle acceleration and pair creation in the black-hole magnetosphere.

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Black holes drive powerful plasma jets to relativistic velocities. This plasma should be collisionless, and self-consistently supplied by pair creation near the horizon. We present general-relativistic collisionless plasma simulations of Kerr-black-hole magnetospheres which begin from vacuum, inject e^{±} pairs based on local unscreened electric fields, and reach steady states with electromagnetically powered Blandford-Znajek jets and persistent current sheets.

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