TITLE:   GCN CIRCULAR
NUMBER:  32299
SUBJECT: IceCube-220629A - IceCube observation of a high-energy neutrino candidate track-like event
DATE:    22/06/30 01:26:47 GMT
FROM:    Marcos Santander at U. Alabama/IceCube  <jmsantander@ua.edu>

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

On 2022-06-29 at 23:51:31.69 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 3.638 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/136783_66879340.amon), more sophisticated reconstruction algorithms have been applied offline, with the direction refined to:

Date: 2022-06-29
Time:  23:51:31.69 UT
RA: 163.92 (+0.80, -0.67 deg  90% PSF containment) J2000
Dec: 4.33 (+0.51, -0.34 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.  We recognize the alert best-fit position falls within the 90% uncertainty region of the recent high-energy neutrino candidate IceCube-220627A (GCN #32277), but given the spatial extent of the error region for the previous alert we remain uncertain as to potential coincidences.

There are no Fermi 4FGL or 3FHL catalog sources in the 90% uncertainty region of the event. The nearest source in either catalog is 4FGL J1050.1+0432 (RA: 162.55 deg, Dec: 4.54 deg J2000, 1.39 deg away from the best-fit event 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