Electron-positron cascade in magnetospheres of supermassive Kerr black holes and the origin of relativistic AGN jets

The avalanche mechanism of plasma production in active galactic nuclei (AGNs) is detailed, and constraints on system parameters required for efficient electron-positron pair cascades are explored. Whether an AGN falls within this favorable parameter range may explain the observed radio-loud versus radio-quiet dichotomy. However, this study shows that cascades produce orders of magnitude fewer pairs than are needed to explain the synchrotron emission observed in luminous jets. This suggests the existence of either an alternative lepton source, namely pair production of photons from the hot accretion flows around AGN central black holes, or matter loading of the jets from the surrounding medium, or, most likely, both. The case of the radio galaxy 3C 120 is considered in detail.