TITLE:   GCN CIRCULAR
NUMBER:  27941
SUBJECT: IceCube-200614A - IceCube observation of a high-energy neutrino candidate track-like event
DATE:    20/06/14 15:38:08 GMT
FROM:    Erik Blaufuss at U. Maryland/IceCube  <blaufuss@umd.edu>

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

On 20/06/14 at  12:41:21.41 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 threshold astrophysical neutrino purity for Bronze alerts is 30% . This alert has an estimated false alarm rate of 1.48 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/134187_72386329.amon), more  
sophisticated reconstruction algorithms have been applied offline, with the direction refined to:

Date: 20/06/14
Time:  12:41:21.41 UT
RA: 33.84 (+4.77 -6.39 deg  90% PSF containment) J2000
Dec: 31.61( +2.75 -2.28 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 four Fermi-LAT 4FGL and 3FHL sources in the 90% containment region. The closest is 4FGL J0220.2+3246, 1.57 deg from the best fit location.  

Upon examination, this event appears to be a starting track event, where the neutrino interaction occurs inside the instrumented volume and the charge muon leaves the detector.  Starting events tend to have poorer angular resolution than standard through-going events. 

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