One-point fluctuation analysis of IceCube neutrino events outlines a significant unassociated isotropic component and constrains the Galactic contribution

Abstract

The origins of the extraterrestrial neutrinos observed in IceCube have yet to be determined. In this study we perform a one-point fluctuation analysis of the six-year high-energy starting event (HESE) shower data, with fixed non-Poissonian contributions from atmospheric, Galactic and some extragalactic components, as well as an isotropic (and weakly non-Poissonian) template. In addition to the star-forming galaxies and blazars, our analysis suggests the presence of an additional isotropic component, not associated with any known class of sources, with best-fit intensity of $(2.8\pm 0.2)\times 10^{-18}(E/100\mathrm{TeV}{)}^{-2.7\pm 0.5}$ ${\mathrm{cm}}^{-2}{\mathrm{s}}^{-1}{\mathrm{sr}}^{-1}{\mathrm{GeV}}^{-1}$. For the first time, we also consider high-energy extrapolations of several phenomenological models for the diffuse Galactic emission (tuned to both local cosmic-ray data and diffuse gamma-ray emission in the GeV-TeV domain). We demonstrate the potential of our framework in discriminating between different scenarios, with possible implications on the physics of cosmic ray transport in the TeV-PeV range.

10 pages, 3 figures, accepted for publication in PRD

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Cited by in corpus (5)

• A Multi-Component Model for the Observed Astrophysical Neutrinos
• Angular power spectrum analysis on current and future high-energy neutrino data
• A Search for Neutrino Point-Source Populations in 7 Years of IceCube Data with Neutrino-count Statistics
• Multi-Component Imaging of the Fermi Gamma-ray Sky in the Spatio-spectral Domain
• First constraints on axion-like particles from Galactic sub-PeV gamma rays