IceCube-221210A - IceCube observation of a high-energy neutrino candidate track-like event

On 22-12-10 at 08:35:11.23 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 0.9539 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 (https://gcn.gsfc.nasa.gov/notices_amon_g_b/137350_7930341.amon), more sophisticated reconstruction algorithms have been applied offline, with the direction refined to: Date: 22-12-10 Time: 08:35:11.23 RA: 332.58 (+9.84/-11.77 deg 90% PSF containment) J2000 Dec: +22.75 (+8.15/-4.13 deg 90% PSF containment) J2000 Due to the event being a short through-going track, the 90% uncertainty contour is especially large. We encourage follow-up by ground and space-based instruments to help identify a possible astrophysical source for the candidate neutrino. Two gamma-ray sources listed in the 4FGL Fermi-LAT catalog are located within 2 deg of the best-fit candidate neutrino position. The sources are 4FGL J2207.1+2222 and 4FGL J2212.0+2356, and are located 0.82 and 1.25 deg away from the best-fit position, respectively. A total of 20 sources listed in the 4FGL catalog are within the 90% containment radius 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 roc@icecube.wisc.edu