Rethinking The Black Hole Corona as an Extended, Multizone Outflow

          @misc{ pirsa_PIRSA:25030112,
            doi = {10.48660/25030112},
            url = {https://pirsa.org/25030112},
            author = {Hankla, Lia},
            keywords = {Strong Gravity},
            language = {en},
            title = {Rethinking The Black Hole Corona as an Extended, Multizone Outflow},
            publisher = {Perimeter Institute},
            year = {2025},
            month = {mar},
            note = {PIRSA:25030112 see, \url{https://pirsa.org}}
          }
          

Abstract

Observations of luminous black holes in X-ray binaries and Seyfert galaxies show power-law emission, thought to originate from photons that inverse Compton scatter off a hot electron cloud. If the coronal electrons are heated by magnetic dissipation, i.e. reconnection or turbulence, then one might expect to observe direct synchrotron emission in the radio/mm from these electrons. However, because timing studies constrain the X-ray emission to be within ~10 rg of the central black hole, the direct synchrotron emission from this compact volume would be strongly self-absorbed until much further away from BH. In this talk, I will question the de facto definition of the corona as a compact, X-ray-emitting region and shift instead to a paradigm where the corona encompasses multiple layers with distinct spectral components. Motivated by highly-magnetized winds found in GRMHD simulations, I will present a model for such an extended, outflowing corona. I will discuss this model in the context of radio-quiet AGN, where recent observations have demonstrated the presence of compact mm emission.