Origin of the high-energy neutrino flux at IceCube

Abstract

We discuss the different components in the astrophysical neutrino flux reaching the Earth and their possible contribution to the high-energy IceCube data. We show that the diffuse flux from cosmic ray interactions with gas in our galaxy implies just 2 events among the 54 event sample. We argue that the neutrino flux from cosmic ray interactions in the intergalactic (intracluster) space depends critically on the transport parameter \(\delta\) describing the energy dependence in the diffusion coefficient of galactic cosmic rays. Our analysis motivates a \(E^{-2.1}\) neutrino spectrum with a drop at PeV energies caused by a change in the cosmic-ray composition at \(E>E_{\rm knee}\). We show that this flux fits well the IceCube data, including the non-observation of the Glashow resonance at 6.3 PeV.