AGILE detection of a candidate gamma-ray precursor to the ICECUBE-160731 neutrino event

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On July 31st, 2016, the ICECUBE collaboration reported the detection of a high-energy starting event induced by an astrophysical neutrino.

• We report here about the search for a gamma-ray counterpart of the ICECUBE-160731 event made with the AGILE satellite.
• No detection was found spanning the time interval of +/- 1 ks around the neutrino event time T0 using the AGILE "burst search" system.
• Looking for a possible gamma-ray precursor in the results of the AGILE-GRID automatic Quick Look procedure over predefined 48-hours time-bins, we found an excess above 100 MeV between one and two days before T0, positionally consistent with the ICECUBE error circle, having a post-trial significance of about 4 sigma.