Description
The IceCube Neutrino Observatory has detected a diffuse flux of astrophysical neutrinos; however, its origin has yet to be fully accounted for. Recently, the first evidence for a source of astrophysical neutrinos was found from the blazar TXS 0506+056. Blazars are active galactic nuclei with a relativistic jet directed toward Earth, thereby providing ample opportunity for high-energy neutrino production. Previous searches for neutrino emission from populations of gamma-ray blazars detected in GeV and higher energies have not observed any significant neutrino excess. More recent hypotheses suggest lower-energy photons may be better indicators of TeV-PeV neutrino production. In this work, we present a likelihood analysis searching for cumulative neutrino emission from blazars in the first catalog of Fermi-LAT sources below 100 MeV (1FLE) using ten years of IceCube muon-neutrino data. We find the results of this analysis to be consistent with a background-only hypothesis. Assuming an E-2 neutrino spectrum and proportionality between the blazars’ MeV gamma-ray fluxes and neutrino flux, we determine the upper limit on the 1FLE blazar energy-scaled neutrino flux to be 1.64 × 10-12 TeV cm-2 s-1 at 90% confidence level.
| Collaboration | IceCube |
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