TITLE:   GCN CIRCULAR
NUMBER:  27651
SUBJECT: IceCube-200425A - IceCube observation of a high-energy neutrino candidate event
DATE:    20/04/26 03:03:15 GMT
FROM:    Marcos Santander at U. Alabama/IceCube  <jmsantander@ua.edu>

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

On 25 April, 2020 at 23:26:46.35 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 threshold astrophysical neutrino purity for Bronze alerts is 30%. This alert has an estimated false alarm rate of 0.5 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/134013_16038252.amon), more sophisticated reconstruction algorithms have been applied offline, with the direction refined to:

Date: 25 April 2020
Time: 23:26:46.35 UT
RA: 100.10 (+4.67/-3.14 deg  90% PSF containment) J2000
Dec: 53.57 (+2.45/-1.60 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 4FGL or 3FHL catalog sources in the 90% uncertainty region. The nearest gamma-ray source in either catalog is 4FGL J0631.0+5626 at RA: 97.75 deg, Dec: 56.45 deg (3.18 deg away from the best-fit event position).

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