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GCN Circular 33773

IceCube-230511A: IceCube observation of a high-energy neutrino candidate
2023-05-11T19:07:15Z (a year ago)
Erik Blaufuss at University of Maryland, College Park <>
The IceCube Collaboration ( reports:

On 2023-05-11 at 18:03:50.10 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 0.49 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 (, more sophisticated reconstruction algorithms have been applied offline, with the direction refined to:

Date: 2023-05-11
Time:  18:03:50.10 UT
RA: 17.05  (+3.57 / -3.40 deg 90% PSF containment) J2000
Dec: +37.08 (+3.16 / -3.69 deg 90% PSF containment) J2000

We encourage follow-up by ground and space-based instruments to help identify a possible astrophysical source for the candidate neutrino.

Three gamma-ray sources listed in the 4FGL-DR3 Fermi-LAT catalog are located within the 90% containment radius of the event. The nearest source is 4FGL J0105.1+3929 located at RA 16.29 deg, Dec +39.50 deg J2000, 2.49 deg away from the best-fit position.

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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