GCN Circular 33403

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

On 2023-03-06 at 10:59:30.41 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 0.71 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/137711_79205800.amon), more 
sophisticated reconstruction algorithms have been applied offline, with 
the direction refined to:

Date: 2023-03-06
Time: 10:59:30.41 UT
RA: 72.86 (+0.87/-0.89 deg  90% PSF containment) J2000
Dec: +34.23 (+0.87/-0.86 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 or 3FHL catalog sources in the 90% uncertainty 
region. The nearest gamma-ray source in either catalog is 4FGL 
J0444.6+3425 at RA: 71.16 deg, Dec: 34.42 deg (1.42 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