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GCN Circular 24910

IceCube-190629A - IceCube observation of a high-energy neutrino candidate event
2019-06-29T22:47:28Z (5 years ago)
Erik Blaufuss at U. Maryland/IceCube <>
The IceCube Collaboration ( reports:

On 29/06/19 at 19:24:15.12 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 0.64 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 (, more  sophisticated reconstruction algorithms have been applied offline, with the direction refined to:

Date: 29/06/19
Time:  19:24:15.12 UT
RA:  27.22 (Dec value too close to pole for accurate error on RA) J2000
Dec: 84.33 (+4.95 -3.13 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.

Two gamma-ray sources listed in the 4FGL Fermi-LAT catalog are located within 2 deg of the best-fit candidate neutrino position. The sources are 4FGL J0151.3+8601 and 4FGL J0151.3+8601, both associated with BL Lac objects, and are located 1.5 and 1.7 deg away from the best-fit position, respectively. Both sources are also listed in the Fermi 3FHL catalog as 3FHL J0249.7+8434 and 3FHL J0148.4+8601, respectively.  A total of 9 sources listed in the 4FGL catalog are contained in a 4 deg radius from the best-fit position, which approximately corresponds to the 90% containment radius of the event.

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

Erik Blaufuss                      email:
Department of Physics
University of Maryland       Phone: 301-405-6077
College Park, MD 20742   Office: PSC 2208E
"Any chance collision, and I light up in the dark."
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