TITLE:   GCN CIRCULAR
NUMBER:  32013
SUBJECT: IceCube-220509A - IceCube observation of a high-energy neutrino candidate track-like event 
DATE:    22/05/09 20:15:22 GMT
FROM:    Erik Blaufuss at U. Maryland/IceCube  <blaufuss@umd.edu>

The IceCube Collaboration (http://icecube.wisc.edu/) reports:

On 2022-05-09 at 18:19:04.12 UT IceCube detected a track-like event with a high probability of being of astrophysical origin. The event was selected by the  ICECUBE_Astrotrack_GOLD alert stream. The average astrophysical neutrino purity for Bronze alerts is 50%. This alert has an estimated false alarm rate of 1.53 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/136615_14688828.amon), more  
sophisticated reconstruction algorithms have been applied offline, with the direction refined to:

Date: 2022-05-09
Time:  18:19:04.12 UT
RA: 334.25 (+2.01, -1.44 deg  90% PSF containment) J2000
Dec: 5.38 (+1.63, -1.65 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 2 known gamma-ray sources in the 90% containment region for the event.  The sources are 4FGL J2215.4+0544 and 4FGL J2212.8+0647.   The closest source in the  4FGL-DR3 Fermi-LAT catalog is 4FGL J2215.4+0544 (333.86 deg, 5.75 deg J2000, 0.54 deg away from the best-fit neutrino candidate 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