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GCN Circular 35983

IceCube-240327A - IceCube observation of a high-energy neutrino candidate track-like event
2024-03-27T13:44:38Z (24 days ago)
A. Zegarelli at Ruhr University Bochum <>
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The IceCube Collaboration ( reports:

On 2024-03-27 at 11:04:49.50 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 for Gold alerts is 50%. This alert has an estimated false alarm rate of 1.0306 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: 2024-03-27
Time:  11:04:49.50 UT
RA: 25.40 (+1.86, -2.36 deg  90% PSF containment) J2000
Dec: 7.78 (+0.69, -0.68 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.

No known gamma-ray sources listed in the Fermi 4FGL-DR4 or 3FHL catalogs are located within the 90% uncertainty region of the event.

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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