[vsnet-grb-info 26042] AMON IC_HAWC 170720: No Neutrino Counterpart detected with ANTARES

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  28142
SUBJECT: AMON IC_HAWC 170720: No Neutrino Counterpart detected with ANTARES
DATE:    20/07/18 21:29:17 GMT
FROM:    Antoine Kouchner at ANTARES Collaboration  <kouchner at apc.in2p3.fr>

Alexis Coleiro (APC/Univ 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 AMON IC-HAWC coincidence alert (Notice https://gcn.gsfc.nasa.gov/notices_amon_nu_em/54519_0.amon <https://gcn.gsfc.nasa.gov/notices_amon_hawc/19170_50.amon>). <br>

No up-going muon neutrino candidate events were detected within 3 degrees from the coincidence coordinates over a time period [17h40 - 21h22 UTC] corresponding to 69% of the “delta_t" interval before the “discovery_time" mentioned in the AMON notice, during which the potential source remained visible in the up-going field of view of ANTARES. <br>

This leads to a preliminary 90% confidence level upper limit on the muon neutrino radiant fluence from a point source located at the coordinates of the coincidence as reported by AMON, of about 15 GeV.cm^-2 over the energy range 3TeV – 3.4PeV (the range corresponding to 5-95% of the detectable flux) for an E^-2 power-law spectrum, and about 25 GeV.cm^-2 (595 GeV - 310TeV) for an E^-2.5 spectrum. These indicative limits have been computed for the “discovery_time” given in the notice. <br>

A search over an extended time window of +/-1 day has also yielded no detection (50% visibility). <br>

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.