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GCN Circular 35485

IceCube-240105A - IceCube observation of a high-energy neutrino candidate track-like event
2024-01-05T15:22:16Z (3 months ago)
Erik Blaufuss at University of Maryland, College Park <>
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The IceCube Collaboration ( reports:

On 2024-01-05 at 12:27:42.57 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 2.64 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: 2024-01-05
Time: 12:27:42.57 UT
RA:    72.69 (+0.53, -0.33 deg  90% PSF containment) J2000
Dec: +11.42 (+0.20, -0.08 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.

One gamma-ray source listed in the 4FGL-DR4 Fermi-LAT catalog is located in the 90% uncertainty of the event. The source is 4FGL J0449.1+112 (associated with PKS 0446+11), located at RA = 72.28 deg and Dec = +11.36 deg (J2000), 0.4 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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