TITLE:   GCN CIRCULAR
NUMBER:  27950
SUBJECT: IceCube-200615A: IceCube observation of a high-energy neutrino candidate event
DATE:    20/06/15 16:11:39 GMT
FROM:    Cristina Lagunas Gualda at DESY  <cristina.lagunas@desy.de>

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

On 20/06/15 at 14:49:17.38 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 0.29 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/134191_17593623.amon), more sophisticated reconstruction algorithms have been applied offline, with the direction refined to:

Date: 20/06/15 
Time: 14:49:17.38 UT
RA: 142.95 (+1.18 -1.45 deg 90% PSF containment) J2000
Dec: 3.66 (+1.19 -1.06 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 J0922.6+0434 located at RA 140.67 deg and Dec 4.58 deg (J2000), at a distance of 2.46 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@icecube.wisc.edu