{
  "submittedHow": "web",
  "subject": "IceCube-250831A - IceCube observation of a high-energy neutrino candidate track-like event",
  "format": "text/plain",
  "submitter": "Erik Blaufuss at University of Maryland, College Park <blaufuss@umd.edu>",
  "createdOn": 1756673076115,
  "bibcode": "2025GCN.41620....1I",
  "circularId": 41620,
  "eventId": "IceCube-250831A",
  "body": "The IceCube Collaboration (http://icecube.wisc.edu/) reports:\nOn 2025-08-31 18:00:45.82 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 2.14 events per year due to atmospheric backgrounds. The IceCube detector was in a normal operating state at the time of detection.\n\nAfter the initial automated alert (https://gcn.gsfc.nasa.gov/notices_amon_g_b/141300_5972385.amon), more sophisticated reconstruction algorithms have been applied offline, with the direction refined to:\n\nDate: 2025-08-31\nTime: 18:00:45.82 UT  \nRA: 105.64 (+0.51, -0.48 deg 90% PSF containment) J2000\nDec: 5.04 (+0.61, -0.50 deg 90% PSF containment) J2000\n\nWe encourage follow-up by ground and space-based instruments to help identify a possible astrophysical source for the candidate neutrino.\n\nNo known gamma-ray sources listed in the Fermi 4FGL-DR4 or 3FHL catalogs are located within the 90% uncertainty region of the event.\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\n"
}