A Multi-Component Model for the Observed Astrophysical Neutrinos

Understand

We propose a multi-component model for the observed diffuse neutrino flux, including the residual atmospheric backgrounds, a Galactic contribution (such as from cosmic ray interactions with gas), an extra-galactic contribution from pp interactions (such as from starburst galaxies) and a hard extragalatic contribution from photo-hadronic interactions at the highest energies (such as from Tidal Disruption Events or Active Galactic Nuclei).

• We demonstrate that this model can address the key problems of astrophysical neutrino data, such as the different observed spectral indices in the high-energy starting and through-going muon samples, a possible anisotropy due to Galactic events, the non-observation of point sources, and the constraint from the extragalatic diffuse gamma-ray background.
• Furthermore, the recently observed muon track with a deposited energy of 4.5 PeV might be interpreted as evidence for the extragalactic photo-hadronic contribution.
• We perform the analysis based on the observed events instead of the unfolded fluxes by computing the probability distributions for the event type and reconstructed neutrino energy.