//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 28950 SUBJECT: AMON Coincidence Alert from the sub-threshold IceCube-HAWC search NuEm-201124A DATE: 20/11/24 17:12:28 GMT FROM: Hugo Ayala at Pennsylvania State University The AMON, IceCube and HAWC collaborations report: The AMON NuEm stream channel found a coincidence alert from the IceCube online neutrino selection + HAWC daily monitoring analysis. The analysis looks for IceCube neutrino events -mostly atmospheric in origin- around the position and transit time of a HAWC cluster of likely gamma rays, as identified in the integrated observations from a single transit, in this case having a duration of 5.99 hours. The HAWC transit interval is from 11, 24, 2020 08:14:10 UT to 11 24, 2020, at 14:13:37 UT (End of the HAWC transit time) The location of the coincidence is reported as RA (J2000): 134.99 deg Dec (J2000): 7.74 deg Location uncertainty (50% containment): 0.23 deg (statistical only). Location uncertainty (90% containment): 0.42 deg (statistical only). The false alarm rate (FAR) of this coincidence is 2.96 per year. We encourage follow-up observations of the alert region contingent on availability of resources and interest, given the quoted FAR. AMON seeks to perform a real-time correlation analysis of the high-energy signals across all known astronomical messengers. More information about AMON can be found in https://www.amon.psu.edu/ Information on the IceCube collaboration: http://icecube.wisc.edu/ Information on the HAWC collaboration: https://www.hawc-observatory.org //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 28953 SUBJECT: AMON IC_HAWC NuEm-201124A: No Neutrino Counterpart detected with ANTARES DATE: 20/11/26 09:04:03 GMT FROM: Antoine Kouchner at ANTARES Collaboration Alexis Coleiro (APC/Université 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 AMON IC-HAWC coincidence alert NuEm-201124A (GCN #28950 https://gcn.gsfc.nasa.gov/gcn3/28950.gcn3). No up-going muon neutrino candidate events were detected within 3 degrees from the coincidence coordinates over a time period [10h48 - 14h13 UTC] corresponding to 57% of the HAWC transit time mentioned in the AMON notice, during which the potential source remained visible in the up-going field of view of ANTARES. 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 19 GeV.cm^-2 over the energy range 4TeV – 4PeV (the range corresponding to 5-95% of the detectable flux) for an E^-2 power-law spectrum, and about 31 GeV.cm^-2 (720 GeV - 380TeV) for an E^-2.5 spectrum. These indicative limits have been computed for the “discovery_time” given in the notice. A search over an extended time window of +/-1 day has also yielded no detection (46% visibility). 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.