GCN Circular 31839

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

On 2022-04-05 at 22:20:03.41 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 2.02 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/136506_15341152.amon), more sophisticated reconstruction algorithms have been applied offline, with the direction refined to:

Date: 2022-04-05
Time:  22:20:03.41 UT
RA: 320.62 (+1.37, -1.13 deg  90% PSF containment) J2000
Dec: 29.06 (+0.94, -0.68 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 sources in the  4FGL-DR2 Fermi-LAT catalog in the 90% uncertainty region.  The nearest source is 4FGL J2115.4+2932 (318.87 deg, 29.55 deg J2000, 1.82 deg away from the best-fit neutrino 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