IceCube astrophysical neutrinos without a spectral cutoff and (10^15-10^17) eV cosmic gamma radiation

Abstract

We present a range of unbroken power-law fits to the astrophysical-neutrino spectrum consistent with the most recent published IceCube data at the 68\% confidence level. Assuming that the neutrinos originate in decays of pi mesons, we estimate accompanying gamma-ray fluxes for various distributions of sources, taking propagation effects into account. We then briefly discuss existing experimental results constraining PeV to EeV diffuse gamma-ray flux and their systematic uncertainties. Several scenarios are marginally consistent both with the KASKADE and CASA-MIA upper limits at (10^15-10^16) eV and with the EAS-MSU tentative detection at ~10^17 eV, given large systematic errors of the measurements. Future searches for the diffuse gamma-ray background at sub-PeV to sub-EeV energies just below present upper limits will give a crucial diagnostic tool for distinguishing between the Galactic and extragalactic models of the origin of the IceCube events.

11 pages, 3 figures, revtex. V.2: references added and corrected

References in corpus (1)

• A Galactic Halo Origin of the Neutrinos Detected by IceCube

Cited by in corpus (10)

• Spectral analysis of the high-energy IceCube neutrinos
• KASCADE-Grande Limits on the Isotropic Diffuse Gamma-Ray Flux between 100 TeV and 1 EeV
• Constraints on the models of the origin of high-energy astrophysical neutrinos
• Fluxes of diffuse gamma rays and neutrinos from cosmic-ray interactions with circumgalactic gas
• Search for astrophysical PeV gamma rays from point sources with Carpet-2
• Carpet-2 search for PeV gamma rays associated with IceCube high-energy neutrino events
• Carpet-2 search for gamma rays above 100 TeV in coincidence with HAWC and IceCube alerts
• Search for a diffuse flux of photons with energies above tens of PeV at the Pierre Auger Observatory
• 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