A multi-messenger study of the total galactic high-energy neutrino emission

TL;DR

This study combines gamma-ray and neutrino observations to identify regions in the Galactic plane where source contributions may explain observed neutrino excesses, advancing multi-messenger astrophysics.

Contribution

It demonstrates the potential of multi-messenger analysis to link gamma-ray emissions with neutrino signals from the Galaxy, highlighting a specific hot region of interest.

Findings

Identification of a gamma-ray hot region coinciding with neutrino excess

Estimation of the galactic contribution to IceCube neutrino flux

Constraints on source spectral index and energy cutoff from observational data

Abstract

A detailed multi-messenger study of the high-energy emission from the Galactic plane is possible nowadays thanks to the observations provided by gamma and neutrino telescopes and could be mandatory in order to obtain a consistent scenario. We show the potential of this approach by using the total gamma flux from the inner galactic region measured by HESS at $1\,{\rm TeV}$ and in the longitude range $-75^\circ < l < 60^\circ$. By comparing the observational data with the expected diffuse galactic emission, we highlight the existence of an extended hot region of the gamma sky where the cumulative sources contribution dominates over the diffuse component. This region approximately coincides with the portion of the galactic plane from which a $\sim 2 \sigma$ excess of showers is observed in IceCube high energy starting events. In the assumption that hadronic mechanisms are responsible for the observed gamma emission, we estimate the total galactic contribution (i.e. including both diffuse and the source components) to the IceCube neutrino signal as a function of the spectral index and energy cutoff of the sources, taking also into account the upper limit on a galactic component provided by Antares.