[vsnet-grb-info 26824] IceCube-201120A: IceCube observation of a high-energy neutrino candidate event

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  28927
SUBJECT: IceCube-201120A: IceCube observation of a high-energy neutrino candidate event
DATE:    20/11/20 13:57:56 GMT
FROM:    Cristina Lagunas Gualda at DESY  <cristina.lagunas at desy.de>

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

On 20/11/20 at 09:44:40.56 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 0.295 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/134715_65785778.amon), more 
sophisticated reconstruction algorithms have been applied offline, with the direction refined to:

Date: 20/11/20
Time: 09:44:40.56  UT
RA: 307.53 (+ 5.34 - 5.59 deg 90% PSF containment) J2000
Dec: 40.77 (+ 4.97 - 2.80 deg 90% PSF containment) J2000 

Due to the topology of this event, with a short distance traversed through the detector, the updated angular uncertainty is significantly larger than average error contours.  

We encourage follow-up by ground and space-based instruments to help identify a possible 
astrophysical source for the candidate neutrino.

There are several Fermi-LAT 4FGL sources inside the 90% localization region. The closest source is 4FGL J2028.6+4110e (Cygnus Cocoon) located at RA 307.17 deg and Dec 41.17 deg (J2000), at a distance of 0.484 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