//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 26037 SUBJECT: Alert from the HAWC Burst Monitor HAWC-191019A DATE: 19/10/19 20:45:38 GMT FROM: Hugo Ayala at Pennsylvania State University The HAWC Collaboration (http://www.hawc-observatory.org/collaboration/) reports: On October 19, 2019, at 20:11:06.18 UT, HAWC detected a burst signal from its Burst Monitoring named HAWC-191019A. This monitor system looks for excesses above the expected background in time windows of 0.2, 1, 10 and 100 seconds. This event was found in the 0.2-second time window starting at the reported trigger time. The position of the alert is RA (J200): 217.501deg Dec (J2000): 25.81 deg Location uncertainty (68% containment): 0.80 deg (statistical only). The monitor system found that this alert has a false alarm rate of 4.6e-3 alert(s) per year. We strongly encourage follow-up observations of the HAWC alert region. The initial automated alert is recorded in here: https://gcn.gsfc.nasa.gov/notices_amon_hawc/8991_1097.amon HAWC is a very-high-energy gamma-ray observatory operating in Central Mexico at latitude 19 deg. north. Operating day and night with over 95% duty cycle, HAWC has an instantaneous field of view of 2 sr and surveys 2/3 of the sky every day. It is sensitive to gamma rays from 300 GeV to 100 TeV. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 26049 SUBJECT: HAWC-191019A: No Neutrino Counterpart detected with ANTARES DATE: 19/10/20 21:16:05 GMT FROM: Antoine Kouchner at ANTARES Collaboration Alexis Coleiro (APC/Univ 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 HAWC-191019A alert (GCN 26037).
No up-going muon neutrino candidate events were detected within 3 degrees from the event coordinates over a time window of [T0-11min, T0+1h] where T0 is the time of the HAWC alert, and during which the potential source remained visible in the up-going field of view of ANTARES. A search over an extended time window of +1 day has also yielded no detection (35% visibility).
This leads to a preliminary 90% confidence level upper limit on the muon-neutrino radiant fluence from a point source of about 90 GeV.cm^-2 over the energy range 6 TeV – 6 PeV (the range corresponding to 5-95% of the detectable flux) for an E^-2 power-law spectrum, and about 110 GeV.cm^-2 (1 TeV GeV - 550 TeV) for an E^-2.5 spectrum, computed for the time of the Swift Busrt Alert.
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. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 26052 SUBJECT: HAWC-191019A: Retraction of burst alert DATE: 19/10/21 14:55:02 GMT FROM: Israel Martinez-Castellanos at UMD/HAWC The HAWC Collaboration (http://www.hawc-observatory.org/collaboration/) reports: After human inspection, the trigger HAWC-191019A is no longer considered to be of astrophysical origin due to a data quality issue in the detector.