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GCN Circular 35665

IceCube-240204A - IceCube observation of a high-energy neutrino candidate track-like event
2024-02-04T15:33:21Z (3 months ago)
Giacomo Sommani at Ruhr-Universität Bochum <>
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The IceCube Collaboration ( reports:

On 2024-02-04 at 09:09:00.44 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 1.6084 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: 2024-02-04
Time:  09:09:00.44
RA: 348.40 (+1.10, -1.00 deg  90% PSF containment) J2000
Dec: +10.28 (+0.72, -0.76 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.

There are no Fermi 4FGL-DR4 or 3FHL catalog sources in the 90% uncertainty region. The nearest gamma-ray source in either catalog is 4FGL J2308.9+1111 at RA: 347.25 deg, Dec: 11.20 deg J2000 (1.46 deg away from the best-fit event 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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