Setting an upper limit for the total TeV neutrino flux from the disk of our Galaxy

TL;DR

This paper establishes an upper limit on the TeV neutrino flux from the Milky Way's disk, considering diffuse and source contributions, and compares it with ANTARES observations to infer the necessity of significant unresolved sources.

Contribution

It provides the first comprehensive upper limit on Galactic TeV neutrino flux incorporating diffuse and source contributions, and assesses the implications for unresolved gamma-ray sources.

Findings

The upper limit constrains the total neutrino flux from the Galactic disk.

The ANTARES observed flux suggests a large unresolved source component.

Current models may underestimate the neutrino flux from Galactic sources.

Abstract

We set an upper limit for the total TeV neutrino flux expected from the disk of our Galaxy in the region $|l|<30^{\circ}$ and $|b|<2^{\circ}$ probed by the ANTARES experiment. We include both the diffuse emission, due to the interaction of cosmic rays with the interstellar medium, and the possible contribution produced by gamma-ray Galactic sources. The neutrino diffuse emission is calculated under different assumptions for the cosmic ray spatial and energy distribution in our Galaxy. In particular, we assume that the total gamma-ray flux produced by all the sources, resolved and unresolved by H.E.S.S., is produced via hadronic interaction and, hence, is coupled with neutrino emission. We compare our total neutrino flux with the recent ANTARES measurement of the neutrino from the Galactic Ridge. We show that the ANTARES best-fit flux requires the existence of a large source component, close to or even larger than the most optimistic predictions obtained with our approach.