TITLE:   GCN CIRCULAR
NUMBER:  31942
SUBJECT: IceCube-220424A - IceCube observation of a high-energy neutrino candidate track-like event
DATE:    22/04/24 01:53:08 GMT
FROM:    Marcos Santander at U. Alabama/IceCube  <jmsantander@ua.edu>

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

On 2022-04-24 at 01:06:24.06 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 Gold alerts is 50%. This alert has an estimated false alarm rate of 1.205 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/136565_2186969.amon), more sophisticated reconstruction algorithms have been applied offline, with the direction refined to:

Date: 2022-04-24
Time:  01:06:24.06 UT
RA: 346.11 (+1.26, -1.33 deg  90% PSF containment) J2000
Dec: 8.91 (+0.95, -1.01 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.

One gamma-ray source listed in the 4FGL-DR3 Fermi-LAT catalog is located within the 90% uncertainty region for the event: the source 4FGL J2306.6+0940 (346.65 deg, 9.67 deg J2000), 0.93 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