TITLE:   GCN CIRCULAR
NUMBER:  28002
SUBJECT: IceCube-200620A: No ANTARES neutrino counterpart 
DATE:    20/06/21 06:42:25 GMT
FROM:    Antoine Kouchner at ANTARES Collaboration  <kouchner@apc.in2p3.fr>

Alexis Coleiro (APC/Universite de Paris) and Damien Dornic (CPPM/CNRS) on behalf of the ANTARES Collaboration. <br>  

Using data from the ANTARES detector, we have performed a follow-up analysis of the recently reported single track-like event IceCube-200620A (GCN 27997<https://gcn.gsfc.nasa.gov/gcn3/27997.gcn3 <https://gcn.gsfc.nasa.gov/gcn3/27997.gcn3>>). The original reconstructed origin was 31.9 degrees below the horizon for ANTARES. <br> 
No up-going muon neutrino candidate events were recorded in a 3 deg cone around 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. <br>
This leads to a preliminary 90% confidence level upper limit on the muon-neutrino fluence from a point source of about 15 GeV.cm^-2 over the energy range 5 TeV –4 PeV (the range corresponding to 5-95% of the detectable flux) for an E^-2 power-law spectrum, and about 30 GeV.cm^-2 (810 GeV - 405 TeV) for an E^-2.5 spectrum. 
A search over an extended time window of +/- 1 day has also yielded no detection (44% visibility). <br>
ANTARES <http://antares.in2p3.fr/ <http://antares.in2p3.fr/>> 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.