Speaker
Description
AGN have long been regarded as prime candidates for high-energy astrophysical neutrino emission, particularly jetted AGN, which make up about 10% of the population. The association of a neutrino and a neutrino flux excess with the blazar TXS 0506+056 confirmed this expectation and revived the debate on jet particle composition. The multimessenger picture changed significantly when the most intense neutrino excess ever observed by IceCube was linked to the archetype of non-jetted AGN (NGC 1068). This raised the question of how neutrinos can be produced in systems lacking relativistic emitting regions. The most plausible site is the plasma surrounding the central supermassive black hole, namely the accretion flow or its immediate environment.
We therefore initiated a systematic study of the accretion properties of all blazars associated with neutrino emission. I will present a new approach based on optical spectroscopic analysis and indirect accretion emission modeling. Preliminar results point toward similar accretion signatures for all neutrino emitting AGN, consistent with slower-than-standard disks, though not slow enough to imply a fully different accretion structure.
Neutrinos signalling a specific transitional accretion regime, more than being a natural product of relativistic jets, may mark a major shift in our understanding of AGN physics.