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GCN Circular 20857

IceCube-170312A - IceCube update on a high-energy neutrino candidate event
2017-03-13T02:29:21Z (7 years ago)
Erik Blaufuss at U. Maryland/IceCube <>
Erik Blaufuss (U. of Maryland) reports on behalf of the IceCube Collaboration (  

On 03 March, 2017 IceCube detected a track-like, very-high-energy event with a possibility of being of astrophysical origin.  The  event was identified by the High Energy Starting Event (HESE) selection.  The IceCube detector was in a normal operating state.   HESE events  have a neutrino vertex inside of the detector (to reduce background) and have a high light level (a proxy for energy).   

After the initial automated alert (, more  sophisticated reconstruction algorithms have been applied offline, with the direction refined to:  

Date: 2017-03-12
Time: 13:49:39.83 UT
RA: 305.15 deg (<+/- 0.5  ra uncertainty> deg  90% PSF containment) J2000 
Dec: -26.61 deg (<+/- 0.5 dec uncertainty> deg 90% PSF containment) J2000  

Additionally, after closer inspection of the event details, it shows signs of being consistent with rare atmospheric muon background events that are expected from the realtime event selection.

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
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