TITLE:   GCN CIRCULAR
NUMBER:  30559
SUBJECT: IceCube-210730A - IceCube observation of a high-energy neutrino candidate track-like event
DATE:    21/07/31 00:19:51 GMT
FROM:    Marcos Santander at U. Alabama/IceCube  <jmsantander@ua.edu>

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

On 2021-07-30 at 22:12:40.629 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 2.542 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/135553_7213992.amon), more sophisticated reconstruction algorithms have been applied offline, with the direction refined to:

Date: 2021-07-30
Time:  22:12:40.629 UT
RA: 105.73 (+2.00, -1.85 deg  90% PSF containment) J2000
Dec: 14.79 (+0.91, -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.

One gamma-ray source listed in the 4FGL Fermi-LAT catalog is located within the 90% uncertainty region of the best-fit candidate neutrino position. The source is 4FGL J0659.7+1416, 0.92 deg away from the best-fit 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