New constraints on the origin of medium-energy neutrinos observed by IceCube

Abstract

The recent IceCube publication claims the observation of cosmic neutrinos with energies down to $\sim 10$ TeV, reinforcing the growing evidence that the neutrino flux in the 10-100 TeV range is unexpectedly large. Any conceivable source of these neutrinos must also produce a $\gamma$-ray flux which degrades in energy en route to the Earth and contributes to the extragalactic $\gamma$-ray background measured by the Fermi satellite. In a quantitative multimessenger analysis, featuring minimalistic assumptions, we find a $\ge 3\sigma$ tension in the data, reaching $\sim 5\sigma$ for cosmic neutrinos extended down to $\sim 1$ TeV, interpreted as evidence for a population of hidden cosmic-ray accelerators.

Comments: 6+1 pages, 4 figures; v2/3: references added, few sentences edited, matches the version published in PRD