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

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 $geq 3sigma$ tension in the data, reaching $sim 5sigma$ for cosmic neutrinos extended down to $sim 1$ TeV, interpreted as evidence for a population of hidden cosmic-ray accelerators.