The gamma-ray and neutrino sky: A consistent picture of Fermi-LAT, Milagro, and IceCube results

TL;DR

This paper presents a unified model for gamma-ray and neutrino emissions from the Galaxy, successfully explaining observations from Fermi-LAT, Milagro, and IceCube, and predicting significant neutrino fluxes at high energies.

Contribution

It introduces a phenomenological model with radially dependent cosmic-ray transport that reproduces multiple observational datasets and predicts high-energy neutrino fluxes.

Findings

Reproduces Fermi-LAT gamma-ray data and Milagro TeV diffuse emission.

Predicts neutrino fluxes exceeding conventional models above 100 TeV.

Accounts for up to 25% of IceCube's observed flux with Galactic sources.

Abstract

We compute the gamma-ray and neutrino diffuse emission of the Galaxy on the basis of a recently proposed phenomenological model characterized by radially dependent cosmic-ray (CR) transport properties. We show how this model, designed to reproduce both Fermi-LAT gamma-ray data and local CR observables, naturally reproduces the anomalous TeV diffuse emission observed by Milagro in the inner Galactic plane. Above 100 TeV our picture predicts a neutrino flux that is about five (two) times larger than the neutrino flux computed with conventional models in the Galactic Center region (full-sky). Explaining in that way up to $\sim 25 \%$ of the flux measured by IceCube, we reproduce the full-sky IceCube spectrum adding an extra-Galactic component derived from the muonic neutrino flux in the northern hemisphere. We also present precise predictions for the Galactic plane region where the flux is dominated by the Galactic emission.