Gamma-ray counterpart of the IceCube neutrinos

M Kachelrieß,A Neronov,D V Semikoz

doi:10.1088/1742-6596/1181/1/012052

Abstract

A γ-ray excess at high Galactic latitudes starting at energies 300 GeV was recently discovered in the data of the Fermi telescope. The multi-TeV γ-ray emission found has spectral characteristics at both low and high Galactic latitudes compatible with those of the IceCube neutrinos in the same sky regions. This suggests that these γ-rays are the counterpart of the IceCube neutrino signal, implying that a sizeable part of the IceCube neutrino flux originates from the Milky Way. The diffuse neutrino and γ-ray signal at high Galactic latitudes may originate either from a nearby cosmic ray “PeVatron” cosmic ray source, an extended Galactic cosmic ray halo or from decays of heavy dark matter particles.

Highlights

The discovery of an extraterrestrial neutrino signal in the TeV–PeV energy range by the IceCube collaboration has opened the era of multi-messenger astronomy [1]
We showed that the γ-ray flux and spectrum at low and high Galactic latitudes are compatible with the flux of the measured neutrino signal, in the energy range where the two signals overlap
We have demonstrated that the properties of the large scale diffuse Galactic γ-ray flux in multiTeV band are compatible with the flux and spectrum of the neutrino signal in 1-100 TeV range, so that the two signals may be considered as different components of one and the same ”multi-messenger” signal in the multi-TeV sky

Summary

Introduction

The discovery of an extraterrestrial neutrino signal in the TeV–PeV energy range by the IceCube collaboration has opened the era of multi-messenger astronomy [1]. Ground-based telescopes or air shower arrays suffer from a high background of events produced by charged CRs. The arrival directions of the CR background events are distributed over large angular scales, similar to the expected γ-ray counterpart of the neutrino signal. We showed that the γ-ray flux and spectrum at low and high Galactic latitudes are compatible with the flux of the measured neutrino signal, in the energy range where the two signals overlap. This suggests that the γ-rays in the multi-TeV band are the counterpart of the soft part of the IceCube neutrinos, while the part with an 1/E2.2 slope at the highest energies has an extragalactic origin.

Published under licence by IOP Publishing Ltd

Conclusions