[vsnet-grb-info 26999] IceCube-201221A: IceCube observation of a high-energy neutrino candidate event

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  29102
SUBJECT: IceCube-201221A: IceCube observation of a high-energy neutrino candidate event 
DATE:    20/12/21 14:32:11 GMT
FROM:    Erik Blaufuss at U. Maryland/IceCube  <blaufuss at umd.edu>

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

On 20/12/21 at 12:36:53.45 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 0.147 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/134817_29175858.amon), more sophisticated reconstruction algorithms have been applied offline, with the direction refined to:

Date: 20/12/21
Time: 12:36:53.45 UT
RA:  261.69 (+2.29  - 2.50 deg  90% PSF containment) J2000
Dec: 41.81 (+1.29  -1.20  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-LAT 4FGL or 3FHL sources inside the 90% localization region. The closest source is 4FGL J1724.2+4005 located at RA 261.05 deg and Dec 40.09 deg (J2000), at a distance of 1.78 degrees from the best-fit location.

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 at icecube.wisc.edu