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GCN Circular 31554

IceCube-220205B - IceCube observation of a high-energy neutrino candidate track-like event
2022-02-05T22:03:46Z (2 years ago)
Marcos Santander at U. Alabama/IceCube <>
The IceCube Collaboration ( reports:

On 2022-02-05 at 20:08:10 UT IceCube detected a track-like event with a high probability of being of astrophysical origin. The event was selected by the ICECUBE_Astrotrack_GOLD alert stream.  The average astrophysical neutrino purity Gold alerts is 50%. This alert has an estimated false alarm rate of 0.734 events per year due to atmospheric backgrounds. The IceCube detector was in a normal operating state at the time of detection.

Due to a technical issue, the automated GCN notice for this event could not be circulated. The initial position was reconstructed by the IceCube online system and the best-fit parameters are listed below:

Date: 2022-02-05
Time:  20:08:10.59 UT
RA: 266.80 deg (J2000)
Dec: -3.58 deg (J2000)
Error radius: 0.51 deg (90%)

Initial signal probability: 59.5%
Initial neutrino energy: 215.9 TeV

Attempts to use a more sophisticated algorithm that provides refined position and error estimates encountered issues, so further studies will have to be performed before an update is available. Given the topology of the light deposition in the detector, we estimate that the initial direction listed above still provides a good characterization of the event.
We encourage follow-up by ground and space-based instruments to help identify a possible astrophysical source for the candidate neutrino.

Several gamma-ray sources listed in the 4FGL Fermi-LAT catalog are located near the best-fit neutrino candidate position, 3 of them within a 1 degree radius. These sources are: 4FGL J1747.8-0316 (0.34 deg away), 4FGL J1744.2-0353 (0.81 deg, associated with the source PKS 1741-03) and 4FGL J1749.8-0303 (0.84 deg). 

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
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