[vsnet-grb-info 25434] IceCube-200410A - IceCube observation of a high-energy neutrino candidate event

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  27534
SUBJECT: IceCube-200410A - IceCube observation of a high-energy neutrino candidate event   
DATE:    20/04/11 01:03:32 GMT
FROM:    Robert Stein at DESY  <robert.stein at desy.de>

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

On 20/04/10 at 23:19:55.49 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 2.55 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/133945_24635982.amon <https://gcn.gsfc.nasa.gov/notices_amon_g_b/133945_24635982.amon>), more 
sophisticated reconstruction algorithms have been applied offline, with the direction refined to:

Date: 20/04/10
Time: 23:19:55.49 UT
RA: 242.58 (+14.05 -13.35  deg 90% PSF containment) J2000
Dec: 11.61 (+7.87 -6.21 deg 90% PSF containment) J2000

This event had a topology with a short distance traversed through the detector, which makes it challenging to reconstruct. The 90% containment region reported by the reconstruction algorithms is thus significantly larger than average error contours.

Due to the large localization uncertainty for this event, there are many Fermi 4FGL catalog sources in the 90% containment region, including 8 sources lying 5 degrees or less from the best-fit position. The closest is 4FGL J1608.7+1029, at RA: 242.18 deg, Dec: 10.49 deg (1.18 deg away from the best-fit event position). 

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

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