Séminaire IPAG

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Electromagnetic fireworks triggered by a black hole feeding on its magnetized plasma corona

jeudi 23 mai 2024 - 11h00

John Mehlhaff - IPAG
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Accreting black holes comprise the central engines for some of the most extraordinary high-energy phenomena in the Universe, including extragalactic radio jets, X-ray binaries, and gamma-ray bursts. Yet, how these objects manipulate their plasma environments to produce the light we observe remains in large part a mystery. Part of the problem is that complicated interactions between different parts of an accreting black hole system are responsible for accelerating the radiating particles. One important – and still poorly understood – interaction is between the black hole itself and its highly magnetized corona (i.e., the dilute plasma atmosphere sandwiching the accretion disk). In this talk, I present our recent efforts to better understand how a black hole feeds on a strongly magnetized accretion disk corona. Our approach involves constructing numerical models based on first-principles plasma simulations. Such simulations are well-adapted to this problem because they self-consistently track the explosive particle acceleration and radiative emission resulting from the black hole-corona coupling. We find that the magnetic scale height of the corona strongly impacts the energy released as radiation and dictates whether a large-scale relativistic jet is launched. These results may shed light on X-ray binary state transitions as well as a peculiar changing-look event observed from the active galactic nucleus 1ES 1927+654.

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