TITLE:   GCN CIRCULAR
NUMBER:  31944
SUBJECT: IceCube-220425A - IceCube observation of a high-energy neutrino candidate track-like event 
DATE:    22/04/25 04:08:40 GMT
FROM:    Marcos Santander at U. Alabama/IceCube  <jmsantander@ua.edu>

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

On 2022-04-25 at 02:44:57.82 UT IceCube detected a track-like event which was selected by the ICECUBE_Astrotrack_GOLD alert stream. We note that, while the average astrophysical neutrino purity for Gold alerts is 50%, this event has a lower probability (~17%). This alert has an estimated false alarm rate of 0.576 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/136568_17854328.amon), more sophisticated reconstruction algorithms have been applied offline, with the direction refined to:

Date: 2022-04-25
Time:  02:44:57.82 UT
RA: 268.24 (+1.98, -1.66 deg  90% PSF containment) J2000
Dec: -10.73 (+1.71, -1.48 deg 90% PSF containment) J2000

One gamma-ray source listed in the 4FGL-DR3 Fermi-LAT catalog is located within the 90% containment region for the neutrino event. The source is 4FGL J1752.6-1010 (RA: 268.16 deg, Dec: -10.18 deg J2000), 0.56 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