Ghost(-particle) stories: Connecting IceCube neutrinos to radio-quiet AGN

The origin of high-energy cosmic rays has remained a mystery since their discovery a century ago. Ghost particles (neutrinos) are an excellent tracer for cosmic rays as they are produced in proton-photon interactions. Neutrinos are not deflected in magnetic fields and give us vital clues towards the origin of cosmic ray accelerators. We expect neutrino emission to be accompanied by an increase in X-ray and gamma-ray emission due to photo-pion production.

We have studied several IceCube neutrino events across the EM spectrum in the past years and have identified radio-quiet AGN as likely source counterparts for many. This has been further supported by the recent neutrino excess of NGC 1068 reported by the IceCube collaboration.

Here, we report on results of a multimessenger study of IceCube events 190331A and 200615A and how our results connect to our understanding of AGN physics, particle acceleration and production near supermassive black holes.