Neutrino Astronomy

1. Carlos Blanco, Dan Hooper, Tim Linden, Elena Pinetti
2. 2509.15421

IceCube Observations have detected a bright 1-10 TeV neutrino flux from NGC 1068, while gamma-ray observations have not detected a corresponding TeV gamma-ray flux. These observations indicate that the neutrinos are produced in dense regions where the gamma-rays are attenuated. The soft gamma-ray spectrum of the NGC 1068 neutrinos has previously been interpreted as evidence that the protons that produce the neutrino spectrum are only accelerated to energies between 100-1000 TeV, and the soft neutrino spectrum corresponds to the exponential cutoff of the parent protons. We propose an alternative hypothesis, where very strong magnetic fields in the acceleration region cause the muons and pions that are produced by hadronic interactions to cool before decaying into neutrinos. Such a scenario would explain the soft neutrino spectrum even in models where NGC 1068 accelerates protons to energies above a PeV. Notably, this scenario produces a different neutrino flavor ratio that may be detectable with future neutrino telescopes.