GCN Circular 24400
Alexis Coleiro (APC/Univ Paris Diderot) 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 high-energy starting event (HESE) neutrino IceCube-190504A (GCN 24392). The reconstructed origin was 18 degrees below the horizon for ANTARES. No up-going muon neutrino candidate events were recorded within 3 degrees of the IceCube event coordinates 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 (74% visibility). This leads to a preliminary 90% confidence level upper limit on the muon-neutrino fluence from a point source of 16 GeV.cm^-2 over the energy range 3.1 TeV - 3.5 PeV (the range corresponding to 5-95% of the detectable flux) for an E^-2 power-law spectrum, and 32 GeV.cm^-2 (630 GeV - 316 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.