{
  "bibcode": "2021GCN.29951....1I",
  "body": "The IceCube Collaboration (http://icecube.wisc.edu/) reports:\n\nOn 21/05/03 at 22:19:32.96 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 0.658 events per year due to atmospheric backgrounds. At the time of the event detection, IceCube was in a test run configuration and therefore no automated alert was circulated via GCN Notices. \n\nOnce the data quality was verified, more sophisticated reconstruction algorithms were applied offline, with the direction refined to:\n\nDate: 21/05/03\nTime: 22:19:32.96 UT\nRA: 143.53 (+7.71, -5.16 deg 90% PSF containment) J2000\nDec: 41.81 (+5.02, -5.68 deg 90% PSF containment) J2000\n\nThe directional uncertainty is larger than usual for this type of alert, as the event was produced by a short muon track clipping a corner of the IceCube detector volume. We encourage follow-up by ground and space-based instruments to help identify a possible astrophysical source for the candidate neutrino.\n\nGiven the large directional uncertainty, there are 14 Fermi-LAT 4FGL sources within the 90% localization region, one of them is also listed in the 3FHL catalog. The nearest source in either catalog is 4FGL J0928.5+4048 (RA: 142.15 deg, Dec: 40.81 deg J2000, 1.44 deg away from the best-fit position).\n\nThe 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",
  "circularId": 29951,
  "createdOn": 1620319237000,
  "email": "jmsantander@ua.edu",
  "subject": "IceCube-210503A: IceCube observation of a high-energy neutrino candidate event",
  "submitter": "Marcos Santander at U. Alabama/IceCube  <jmsantander@ua.edu>",
  "eventId": "IceCube-210503A"
}