Würzburg 2018 – scientific programme

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EP: Fachverband Extraterrestrische Physik

EP 12: Astrophysics I - High-energy and Relativistic Astrophysics

EP 12.2: Talk

Thursday, March 22, 2018, 17:45–18:00, BSZ - Pabel HS

The blazar family as a joint source of neutrinos and cosmic-ray nuclei — •Xavier Rodrigues, Anatoli Fedynitch, Shan Gao, Denise Boncioli, and Walter Winter — DESY Zeuthen

The origin of the ultra-high-energy cosmic rays (UHECR) and the astrophysical neutrinos observed by IceCube is a subject still shrouded in mystery. PeV-energy neutrinos must originate from (photo-)hadronic interactions in astrophysical environments that are able to accelerate and confine UHECR. However, the stacking analyses by IceCube have not yet unveiled a correlation between the directions of astrophysical neutrinos and known gamma-ray sources. This may indicate that a population of yet undetected extragalactic objects may be responsible for the cosmic-ray and diffuse neutrino fluxes. In this work we investigate blazars (relativistic outflows driven by super-massive black holes) as multi-messenger sources, under the assumption that they contain accelerated nuclei heavier than protons in the jet. Our calculation includes a sophisticated model of photo-nuclear interactions within the source and a three-zone model to take into account external photon fields in Flat Spectrum Radio Quasars (FSRQs). We then compute and study the emission of cosmic rays and neutrinos across the blazar sequence. Our results demonstrate that the neutrino and cosmic ray production efficiencies are inversely related to each other with respect to the source luminosity, and that there is no ideal source for the emission of both messengers. In our latest calculations, we study the contributions from different blazar classes to the diffuse cosmic-ray and neutrino flux.