TITLE: GCN CIRCULAR NUMBER: 31085 SUBJECT: IceCube-211116A : IceCube observation of a high-energy neutrino candidate track-like event DATE: 21/11/16 11:53:55 GMT FROM: Cristina Lagunas Gualda at DESY <cristina.lagunas@desy.de> The IceCube Collaboration (http://icecube.wisc.edu/) reports: On 2021/11/16 at 10:33:16.05 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 1.941 events per year due to atmospheric backgrounds. The IceCube detector was in a normal operating state at the time of detection. Due to a technical problem, the initial automated alert was not issued. Nonetheless, sophisticated reconstruction algorithms have been applied offline, with the direction refined to: Date: 2021/11/16 Time: 10:33:16.05 UT RA: 42.45 (+1.39 -1.50 deg 90% PSF containment) J2000 Dec: +0.15 (+0.98 -0.94 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-LAT 4FGL sources inside of the 90% error contour. The closest source is 4FGL J0253.2-0124, located at RA 43.32 deg and dec -1.4 deg (J2000), 1.78 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 roc@icecube.wisc.edu