Interpretation of astrophysical neutrinos observed by IceCube experiment by setting Galactic and extra-Galactic spectral components

TL;DR

This paper models the astrophysical neutrino flux observed by IceCube by combining Galactic diffuse emission based on a new cosmic-ray transport model with an extragalactic component, explaining the observed spectrum and distribution.

Contribution

It introduces a phenomenological model of Galactic cosmic-ray transport to explain the diffuse Galactic neutrino emission observed by IceCube, integrating it with extragalactic sources.

Findings

Galactic diffuse neutrino flux can explain part of IceCube data

Adding extragalactic component improves spectral fit

Model aligns with neutrino observations across the sky

Abstract

The last IceCube catalog of High Energy Starting Events (HESE) obtained with a livetime of 1347 days comprises 54 neutrino events equally-distributed between the three families with energies between 25 TeV and few PeVs. Considering the homogeneous flavors distribution (1:1:1) and the spectral features of these neutrinos the IceCube collaboration claims the astrophysical origin of these events with more than $5\sigma$. The spatial distribution of cited events does not show a clear correlation with known astrophysical accelerators leaving opened both the Galactic and the extra-Galactic origin interpretations. Here, we compute the neutrino diffuse emission of our Galaxy on the basis of a recently proposed phenomenological model characterized by radially-dependent cosmic-ray (CR) transport properties. We show that the astrophysical spectrum measured by IceCube experiment can be well explained adding to the diffuse Galactic neutrino flux (obtained with this new model) a extra-Galactic component derived from the astrophysical muonic neutrinos reconstructed in the Northern hemisphere. A good agreement between the expected astrophysical neutrino flux and the IceCube data is found for the full sky as well as for the Galactic plane region.