TITLE:   GCN CIRCULAR
NUMBER:  33911
SUBJECT: IceCube-230603A - IceCube observation of a high-energy neutrino candidate track-like event
DATE:    23/06/03 15:14:00 GMT
FROM:    Dr. Massimiliano Lincetto at Ruhr-Universitaet Bochum <lincetto@astro.rub.de>

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

On 2023-06-03 at 05:00:47.13 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 1.24 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/138005_24780443.amon), more
sophisticated reconstruction algorithms have been applied offline, with
the direction refined to:

Date: 2023-06-03
Time:  05:00:47.13 UT
RA: 68.20 (+2.62 / -3.06 deg  90% PSF containment) J2000
Dec: +24.21 (+2.08 / -2.59 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.

No gamma-ray sources listed in the 4FGL-DR3 Fermi-LAT catalog are
located within the 90% uncertainty region. The nearest source is 4FGL
J0439.2+2151, located 2.79 deg away from the best-fit alert 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