GCN Circular 45307
Subject
IceCube-260807A - IceCube observation of a high-energy neutrino candidate track-like event
Event
Date
2026-08-07T10:05:17Z (2 months ago)
From
Cristobal Zilleruelo Cañas at DESY <cristobal.zilleruelo.canas@desy.de>
Via
Web form
The IceCube Collaboration (http://icecube.wisc.edu/) reports:
On 26-08-07 at 06:04:41.70 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.
Documentation regarding the alert streams and their astrophysical purity can be found here: https://gcn.nasa.gov/missions/icecube.
This alert has an estimated false alarm rate of 3.913 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/142963_68892416.amon), more sophisticated reconstruction algorithms have been applied offline, with the direction refined to:
Date: 26-08-07
Time: 06:04:41.70 UT
RA: 325.37 (+4.26/-7.82 deg 90% PSF containment) J2000
Dec: 0.07 (+0.98/-1.77 deg 90% PSF containment) J2000
As announced in GCN Circular 43419 (https://gcn.nasa.gov/circulars/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, where YYMMDD indicates the date of the event and X is a letter distinguishing multiple alerts on the same day. The download link is provided through the GCN schema distributed via Kafka.
Detailed documentation describing the alert distribution, schemas, and probability maps is available at: https://gcn.nasa.gov/missions/icecube.
7 gamma-ray sources from the Fermi FL16Y catalog are located within the 90% uncertainty region of this event. The closest source is FL16Y J2136.6+0041 at RA = 324.150° and Dec = 0.685° (J2000), with an angular separation of 1.365° from the best-fit event position.
We report here sources within the 90% confidence contour available in the multi-order probability map, rather than those selected using the simplified rectangular error-box reported in this Circular.
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