TITLE:   GCN CIRCULAR
NUMBER:  34261
SUBJECT: IceCube-230725A - IceCube observation of a high-energy neutrino candidate track-like event
DATE:    23/07/25 23:24:15 GMT
FROM:    Marcos Santander at U of Alabama <jmsantander@ua.edu>


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

On 23-07-25 at 21:30:51.06 UT IceCube detected a track-like event with a high 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 1.677 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/138193_21103478.amon), more sophisticated reconstruction algorithms have have been applied offline, with the direction refined to:

Date: 23-07-25
Time: 21:30:51.06  UT
RA: 327.04 (+2.27 / -2.03  90% PSF containment) J2000
Dec: +12.33 (+1.80 / -1.36 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. One Fermi 4FGL-DR3 or 3FHL catalog source is located in the 90% uncertainty region. The source is 4FGL J2150.8+1118, located at RA 327.70, Dec 11.31, 1.21 deg away from the best-fit alert 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 .