TITLE:   GCN CIRCULAR
NUMBER:  34891
SUBJECT: IceCube-231027A - IceCube observation of a high-energy neutrino candidate track-like event
DATE:    23/10/27 12:48:52 GMT
FROM:    Massimiliano Lincetto at Ruhr-Universitaet Bochum <lincetto@astro.ruhr-uni-bochum.de>

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

On 23-10-27 at 04:16:10.44 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 0.1472 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/138487_60138479.amon), more sophisticated reconstruction algorithms have been applied offline, with the direction refined to:

Date: 23-10-27
Time: 04:16:10.44 UT
RA: 267.16 (+3.35/-3.40 deg 90% PSF containment) J2000
Dec: +46.96 (+2.25/-2.88 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.

Seven gamma-ray sources listed in the 4FGL-DR3 Fermi-LAT catalog are located in the 90% containment region. The closest source is 4FGL J1747.9+4704 at RA 266.99, Dec +47.07, 0.16 deg away from the best-fit 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