TITLE:   GCN CIRCULAR
NUMBER:  43512
SUBJECT: IceCube-260125A - IceCube observation of a high-energy neutrino candidate track-like event
DATE:    26/01/25 11:33:55 GMT
FROM:    A. Zegarelli at Ruhr University Bochum <azegarelli@icecube.wisc.edu>

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

On 26-01-25 at 10:09:39.88 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 for Bronze alerts is 30%.
This alert has an estimated false alarm rate of 1.9783 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/141985_63695019.amon), more sophisticated reconstruction algorithms have been applied offline, with the direction refined to:

Date: 26-01-25
Time: 10:09:39.88 UT
RA: 243.72 (+0.52/-0.56 deg 90% PSF containment) J2000
Dec: 6.69 (+0.62/-0.61 deg 90% PSF containment) J2000

As announced in GCN Circular 43419, IceCube alert notices for high-energy track alerts are now also streamed via Kafka. IceCube Gold/Bronze track alerts are available on the Kafka topic 'gcn.notices.icecube.gold_bronze_track_alerts'.
The probability distribution of the true neutrino direction, allowing the extraction of precise 90% containment regions around the best-fit direction, is now available for revised reconstruction of high-energy track alerts.
The corresponding sky map is distributed as a FITS file and follows the explicit naming convention IceCube-YYMMDDX (e.g. IceCube-260125A, for this alert), where YYMMDD indicates the date of the event and X is a letter distinguishing multiple alerts on the same day. The download link (e.g., for this alert https://roc-2.icecube.wisc.edu/public/alerts/IceCube-260125A_skymap_probdensity_multiorder.fits.gz) is provided through the GCN schema distributed via Kafka.
Additional information will be soon available at https://gcn.nasa.gov/missions/icecube.
In the near future, classical GCN stream will be deactivated.

No known gamma-ray sources listed in the Fermi 4FGL-DR4 or 3FHL catalogs are located within the 90% uncertainty region of this event.

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