Nuclei in high-energy neutrino sources: A multimessenger study of in-source propagation

Abstract: The joint observation of astrophysical sources in gamma rays and neutrinos can provide invaluable insight into the physical conditions of the source, including its size, particle densities, and acceleration and production mechanisms. In this work, we investigate the role of nuclear composition in high-energy astrophysical environments. Using NGC 1068 as a representative example, we perform detailed Monte Carlo simulations of nuclear and electromagnetic cascades within the source and study the imprints of the injected nuclear composition on the resulting neutrino and gamma-ray emissions. We further discuss the importance of MeV-GeV gamma-ray observations for constraining the source composition in the context of future gamma-ray experiments. A dedicated re-analysis of archival COMPTEL observations is also presented.