GCN Circular 28889

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

On 20/11/15 at 02:07:26.21 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 1.523 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/134699_70289682.amon), more sophisticated reconstruction algorithms have been applied offline, with the direction refined to:

Date: 20/11/15
Time:  02:07:26.21 UT
RA: 195.12 (+ 1.27 - 1.49  deg  90% PSF containment) J2000
Dec: 1.38 (+ 1.30 - 1.11 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 J1250.6+0217 located at RA 192.65 deg and Dec 2.29 deg (J2000), at a distance of 2.63 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