TITLE:   GCN CIRCULAR
NUMBER:  36196
SUBJECT: IceCube-240419A - IceCube observation of a high-energy neutrino candidate track-like event
DATE:    24/04/20 14:48:36 GMT
FROM:    Giacomo Sommani at Ruhr-Universität Bochum <gsommani@icecube.wisc.edu>

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

On 2024-04-19 at 23:25:41.05 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 3.426 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/139303_27647445.amon), more sophisticated reconstruction algorithms have been applied offline, with the direction refined to:

Date: 2024-04-19
Time: 23:25:41.05 UT
RA: 73.17 (+2.60, -3.74 deg  90% PSF containment) J2000
Dec: 1.64 (+1.27, -1.09 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-LAT source (listed in the 4FGL-DR4 or 3FHL catalogs) is located within the 90% uncertainty region: 4FGL J0502.6+0036, at RA: 75.65 deg, Dec: 0.61 deg (2.69 deg away from the best-fit 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