GCN Circular 19772

D. Dornic (CPPM/CNRS), A. Coleiro (APC/Universite Paris Diderot), report on behalf of the ANTARES Collaboration:

Using data from the ANTARES detector, we have performed a follow-up analysis of the recently reported single extremely high-energy (EHE) neutrino
+IceCube-160731A (AMON IceCube HESE 128290 6888376). Its position is -28.1 degrees below the horizon for ANTARES which could yield to an up-going
+event at the time of the event.

ANTARES is the largest neutrino detector installed in the Mediterranean Sea primarily sensitive to astrophysical neutrinos in the TeV-PeV energy
+range.  At 10 TeV, the median angular resolution for muon neutrinos is below 0.5 degrees. In the range 1-100 TeV, ANTARES has the best
+sensitivity to this position in the sky.

No up-going muon neutrino candidate events were recorded within three degrees of the IceCube event coordinates during a +/- 1h time-window
+centered on the IceCube event time. A search on an extended time window of +/- 1 day has also yielded no detection (50% visibility probability).

This yields a preliminary 90% upper limit on the fluence from a point source of  14 GeV.cm^-2 (2.8 TeV-3.1PeV, energy range corresponding to
+5-95% of the energy distribution) and 27 GeV.cm^-2 (0.4-280 TeV) assuming a E^-2 and E^-2.5 power law spectrum, respectively.

[GCN OPS NOTE(05aug16):  Per operator, the double TITLE-block was removed.]