PeV neutrinos from interactions of cosmic rays with the interstellar medium in the Galaxy

TL;DR

This paper proposes that the high-energy neutrinos detected by IceCube from the inner Galaxy originate from cosmic ray interactions with the interstellar medium, linking gamma-ray and neutrino emissions in a self-consistent model.

Contribution

It provides a self-consistent interpretation connecting IceCube neutrino signals with Fermi gamma-ray observations, highlighting cosmic ray interactions in the Galaxy as the common source.

Findings

Neutrino flux aligns with the high-energy extrapolation of gamma-ray spectrum.

Cosmic rays have a hard spectrum with slope > -2.4 and cutoff > 10 PeV.

Neutrino and gamma-ray fluxes originate from the Norma arm and Galactic Bar.

Abstract

We present a self-consistent interpretation of the of very-high-energy neutrino signal from the direction of the inner Galaxy, which is a part of the astronomical neutrino signal reported by IceCube. We demonstrate that an estimate of the neutrino flux in the E>100 TeV energy range lies at the high-energy power-law extrapolation of the spectrum of diffuse gamma-ray emission from the Galactic Ridge, as observed by Fermi telescope. This suggests that IceCube neutrino and Fermi/LAT gamma-ray fluxes are both produced in interactions of cosmic rays with the interstellar medium in the Norma arm and/or in the Galactic Bar. Cosmic rays responsible for the gamma-ray and neutrino flux are characterised by hard spectrum with the slope harder than -2.4 and cut-off energy higher than 10 PeV.