TITLE:   GCN CIRCULAR
NUMBER:  34797
SUBJECT: IceCube-231004A - IceCube observation of a high-energy neutrino candidate track-like event
DATE:    23/10/04 15:46:15 GMT
FROM:    Massimiliano Lincetto at Ruhr-Universitaet Bochum <lincetto@astro.ruhr-uni-bochum.de>

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

On 2023-10-04 at 14:39:41.18 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 0.4490 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/138415_56188508.amon), more sophisticated reconstruction algorithms have been applied offline, with the direction refined to:

Date: 2023-10-04 
Time:  14:39:41.18 UT
RA: 143.79 (+1.10, -1.01 deg  90% PSF containment) J2000
Dec: -25.04 (+1.03, -1.21 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.

There are no Fermi 4FGL-DR4 or 3FHL catalog sources in the 90% uncertainty region of the event. The nearest gamma-ray source in either catalog is 4FGL J0927.2+2454 at RA: 141.82 deg, Dec: -24.90 deg (1.79 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