GCN Circular 28509
Subject
IceCube-200926B: IceCube observation of a high-energy neutrino candidate event
Date
2020-09-26T23:56:11Z (4 years ago)
From
Erik Blaufuss at U. Maryland/IceCube <blaufuss@umd.edu>
The IceCube Collaboration (http://icecube.wisc.edu/) reports:
On 2020-09-26 22:35:29.22 UT IceCube detected a track-like event with a moderate probability of being of astrophysical origin. The event was selected by the ICECUBE_Astrotrack_Bronze alert stream. The average astrophysical neutrino purity for Bronze alerts is 30%. This alert has an estimated false alarm rate of 1.29 events per year due to atmospheric backgrounds. The IceCube detector was in a normal operating state at the time of detection.
After the initial automated alert (https://gcn.gsfc.nasa.gov/notices_amon_g_b/134535_41069485.amon), more
sophisticated reconstruction algorithms have been applied offline, with the direction refined to:
Date: 20/09/26
Time: 22:35:29.22 UT
RA: 184.75 (+3.64 -1.55 deg 90% PSF containment) J2000
Dec: 32.93 (+1.15 -0.91 deg 90% PSF containment) J2000
We do note a significant shift and increased error estimate in the refined RA position with respect to the automated alert. This event had a relatively short track within the instrumented region of our detector, leading to some ambiguity in the final direction. We encourage follow-up by ground and space-based instruments to help identify a possible astrophysical source for the candidate neutrino.
There are no Fermi-LAT 4FGL or 3FHL sources inside the 90% localization region. The closest source is 4FGL J1220.1+3432 located at RA 185.05 deg and Dec 34.54 deg (J2000), at a distance of 1.63 degrees from the best-fit location.
The IceCube Neutrino Observatory is a cubic-kilometer neutrino detector operating at the geographic South Pole, Antarctica. The IceCube realtime alert point of contact can be reached at roc@icecube.wisc.edu