On high-energy neutrino radiation of quasars and active galactic nuclei

The nature of the cores in quasars and active galactic nuclei is still controversial, though massive black holes or magnetoids (spinars) seem to be the most plausible models for core activity. It is difficult to distinguish between these by observations of electromagnetic radiation alone and we suggest in this paper that high-energy ($$E\gtrsim1\enspace\text{TeV}$$) neutrinos can be a useful tool for solving the problem. A structureless magnetoid, and a black hole surrounded by a dense shell of gas or a ‘gas’ of X-ray photons, can be convincingly distinguished by measuring the ratio of neutrino ($$E_\nu\gtrsim1\enspace\text{TeV}$$) to gamma-ray ($$E_\gamma\gtrsim 70 \enspace\text{TeV}$$) fluxes. The possibility of a cocooned black hole (i.e. a black hole surrounded by a gaseous shell rarefied inside and dense outside) and of particle acceleration in the cavity are also discussed.