TITLE: GCN CIRCULAR NUMBER: 26811 SUBJECT: IceCube-200117A: No Neutrino Counterpart in ANTARES data DATE: 20/01/18 13:41:55 GMT FROM: Antoine Kouchner at ANTARES Collaboration Alexis Coleiro (APC/Universite de Paris) and Damien Dornic (CPPM/CNRS) on behalf of the ANTARES Collaboration.

Using data from the ANTARES detector, we have performed a follow-up analysis of the recently reported single track-like event IceCube-200117A (GCN 26802< https://gcn.gsfc.nasa.gov/gcn3/26802.gcn3>). The original reconstructed origin was 17.8 degrees below the horizon for ANTARES.

No up-going muon neutrino candidate events were recorded at the location of the IceCube event coordinates (accounting for the reported uncertainties) during a +/- 1h time-window centered on the IceCube event time, and over which the potential source remained visible all time. A search over an extended time window of +/- 1 day has also yielded no detection (32% visibility).

This leads to a preliminary 90% confidence level upper limit on the muon-neutrino fluence from a point source of 15 GeV.cm^-2 over the energy range 6.8 TeV – 6.3 PeV (the range corresponding to 5-95% of the detectable flux) for an E^-2 power-law spectrum, and 29 GeV.cm^-2 (1 TeV - 613 TeV) for an E^-2.5 spectrum.

ANTARES > is the largest undersea neutrino detector (Mediterranean Sea) and it is primarily sensitive to astrophysical neutrinos in the TeV-PeV energy range. At 10 TeV, the median angular resolution for muon neutrinos is about 0.5 degrees. In the range 1-100 TeV ANTARES has a competitive sensitivity to this position in the sky.