TITLE:   GCN CIRCULAR
NUMBER:  33870
SUBJECT: IceCube-230524A - IceCube observation of a high-energy neutrino candidate track-like event
DATE:    23/05/24 13:50:23 GMT
FROM:    Dr. Massimiliano Lincetto at Ruhr-Universitaet Bochum <lincetto@astro.rub.de>

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

On 2023-05-24 at 11:09:36.24 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 Bronze alerts is 30%.

This alert has an estimated false alarm rate of 4.25 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/137971_11526243.amon), more
sophisticated reconstruction algorithms have been applied offline, with
the direction refined to:

Date: 2023-05-24
Time:  11:09:36.24 UT
RA: 318.43 (+3.12 / -2.59 deg  90% PSF containment) J2000
Dec: +2.84 (+2.55 / -2.43 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.

Two gamma-ray sources listed in the 4FGL Fermi-LAT catalog are located
within the 90% uncertainty region. The sources are 4FGL J2110.3+0404
and 4FGL J2109.6+0440 located 1.50 and 2.10 deg away from the best-fit
position, respectively.

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