Unveiling the nature of galactic TeV sources with IceCube results

TL;DR

This paper analyzes IceCube neutrino data to distinguish between diffuse and source contributions to galactic TeV gamma-ray emission, constraining the fraction of hadronic sources in the galaxy.

Contribution

It combines gamma-ray observations and theoretical models to estimate the maximum fraction of Galactic TeV sources with hadronic origins compatible with IceCube data.

Findings

Less than 40% of TeV gamma-ray sources are hadronic in nature.

The cumulative source neutrino flux is constrained to be below 2.6 x 10^{-10} cm^{-2}s^{-1}.

Results help differentiate diffuse emission from point source contributions.

Abstract

IceCube collaboration reported the first high-significance observation of the neutrino emission from the Galactic disk. The observed signal can be due to diffuse emission produced by cosmic rays interacting with interstellar gas but can also arise from a population of sources. In this paper, we evaluate both the diffuse and source contribution by taking advantage of gamma-ray observations and/or theoretical considerations. By comparing our expectations with IceCube measurement, we constrain the fraction of Galactic TeV gamma-ray sources (resolved and unresolved) with hadronic nature. In order to be compatible with the IceCube results, this fraction should be less than $\sim 40\%$ corresponding to a cumulative source flux $\Phi_{\nu, \rm s} \le 2.6 \times 10^{-10} cm^{-2}s^{-1}$ integrated in the 1-100 TeV energy range.