Multi-messenger gamma-ray counterpart of the IceCube neutrino signal

Abstract

A signal of high-energy extraterrestrial neutrinos from unknown source(s) was recently discovered by the IceCube experiment. Neutrinos are always produced together with gamma-rays, but the gamma-ray flux from extragalactic sources is suppressed due to attenuation in the intergalactic medium. We report the discovery of a gamma-ray excess at high Galactic latitudes starting at energies 300 GeV in the data of the Fermi telescope. We show that the multi-TeV gamma-ray diffuse emission has spectral characteristics at both low and high Galactic latitudes compatible with those of the IceCube high neutrino signal in the same sky regions. This suggests that these gamma-rays are the counterpart of the IceCube neutrino signal, implying that a sizable part of the IceCube neutrino flux originates from the Milky Way. We argue that the diffuse neutrino and gamma-ray signal at high Galactic latitudes originates either from previously unknown nearby cosmic ray "PeVatron" source(s), an extended Galactic CR halo or from decays of heavy dark matter particles.

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• Galactic contribution to the high-energy neutrino flux found in track-like IceCube events
• Where do IceCube neutrinos come from? Hints from the diffuse gamma-ray flux
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• Probing dark matter signals in neutrino telescopes through angular power spectrum
• High-Energy Galactic Cosmic Rays (Astro2020 Science White Paper)
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• Carpet-2 search for PeV gamma rays associated with IceCube high-energy neutrino events
• Probing the Galactic neutrino flux at neutrino energies above 200 TeV with the Baikal Gigaton Volume Detector
• Spatial and temporal structure of EAS reflected Cherenkov light signal
• Neutrinos from the gamma-ray source eHWC J1825-134: predictions for Km${}^3$ detectors
• Mapping large-scale diffuse gamma-ray emission in 10-100 TeV band with Cherenkov telescopes
• Carpet results on astrophysical gamma rays above 100 TeV
• Upper limits on the isotropic diffuse flux of cosmic PeV photons from Carpet-2 observations
• On the contribution of cosmic-ray interactions in the circumgalactic gas to the observed high-energy neutrino flux
• Polarized synchrotron data and the structure of the Galactic magnetic field
• Estimation of Baryon Asymmetry from Dark Matter Decaying into IceCube Neutrinos
• New limit on high Galactic latitude PeV gamma-ray flux from Tibet AS-gamma data