Speaker
Description
The cores of active galactic nuclei (AGN) are potential accelerators of 10-100 TeV cosmic rays, which in turn can produce high-energy neutrinos. This hypothesis has been supported by compelling evidence of a TeV neutrino signal from the nearby active galaxy NGC 1068. However, the specific site and mechanism of cosmic ray acceleration remain open questions. One promising candidate is magnetized turbulence in the corona of the central supermassive black hole. Using first-principles fully kinetic (PIC) simulations, we demonstrate that the accelerated particles are extracted from the thermal pool in magnetic reconnection layers that form self-consistently within the turbulent cascade. These injected particles are then stochastically accelerated via non-resonant interactions with large-scale turbulent fluctuations. We characterize the stochastic acceleration process using an effective diffusion coefficient in momentum space that we derive directly from the PIC simulations. We apply our first-principles simulation results to investigate cosmic ray acceleration in the corona of NGC 1068, showing that when the turbulent magnetic energy density exceeds 1% of the rest mass energy density, proton acceleration by magnetized turbulence can naturally account for the observed IceCube neutrino signal from NGC 1068.
