TITLE:   GCN CIRCULAR
NUMBER:  30342
SUBJECT: IceCube-210629A - IceCube observation of a high-energy neutrino candidate track-like event
DATE:    21/06/29 19:30:33 GMT
FROM:    Marcos Santander at U. Alabama/IceCube  <jmsantander@ua.edu>

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

On 2021-06-29 at 18:09:44 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 2.085 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/135440_3139778.amon), more sophisticated reconstruction algorithms have been applied offline, with the direction refined to:

Date: 2021-06-29
Time:  18:09:44 UT

RA: 340.75 (+ 1.11 - 2.23 deg  90% PSF containment) J2000
Dec: +12.94 (+ 0.91 - 0.93 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 J2252.6+1245 at RA: 343.17 deg, Dec: 12.75 deg J2000 (2.36 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