An NGC 1068-informed Understanding of Neutrino Emission of the Active Galactic Nucleus TXS 0506+056

Abstract

We present arguments that the neutrinos observed by IceCube from the active galactic nucleus TXS 0506+056 may originate near its core and not in the blazar jet. The origin of the neutrinos is consistent with the mechanism that produces the neutrino flux observed from the active galaxies NGC 1068 and NGC 4151, but requires an Eddington luminosity cosmic-ray flux to compensate for its larger distance. Like NGC 1068, the source is characterized by episodes of high X-ray emission and is gamma-ray-obscured during the 2014 burst, and there is evidence that this is also the case during the short burst in 2017 that produced IC-170922. The observations may be explained as a flux originating in an obscured core within 10 ∼ 100 Schwarzschild radii from the central black hole, which is not transparent to gamma rays from the decay of neutral pions accompanying the neutrinos.

Keywords

• Active galactic nuclei
• Blazars
• High energy astrophysics
• Gamma-rays
• Cosmic rays
• Neutrino astronomy