IceCube-230823A
GCN Circular 34527
Subject
IceCube-230823A - IceCube observation of a high-energy neutrino candidate track-like event
Date
2023-08-23T13:52:18Z (2 years ago)
From
Massimiliano Lincetto at Ruhr-Universitaet Bochum <lincetto@astro.ruhr-uni-bochum.de>
Via
Web form
The IceCube Collaboration (http://icecube.wisc.edu/) reports:
On 2023-08-23 at 08:26:14.59 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 0.5131 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/138283_14780365.amon), more sophisticated reconstruction algorithms have been applied offline, with the direction refined to:
Date: 2023-08-23
Time: 08:26:14.59 UT
RA: 17.93 (+0.36, -0.38 deg 90% PSF containment) J2000
Dec: -12.10 (+0.23, -0.24 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-DR4 or 3FHL catalog sources in the 90% uncertainty region of the event. The nearest gamma-ray source in either catalog is 4FGL J0110.7-1254 at RA: 17.69 deg, Dec: -12.91 deg (0.84 deg away from the best-fit alert 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
GCN Circular 34528
Subject
IceCube-230823A: Event likely due to background
Date
2023-08-23T15:37:33Z (2 years ago)
From
Marcos Santander at U of Alabama <jmsantander@ua.edu>
Via
legacy email
The IceCube Collaboration (http://icecube.wisc.edu/) reports:
On 23/08/23 IceCube reported a track-like event with a high probability of being of astrophysical origin (https://gcn.nasa.gov/circulars/34527). After further study, we now believe this event to likely be due to a highly inclined muon bundle. Muon bundles are a background arising from down-going cosmic-ray air showers and are not from a neutrino of astrophysical origin.
This conclusion is driven by observations with the IceTop surface array portion of IceCube at the time of the alert. The IceTop surface array detects charged particles from cosmic ray induced extensive air showers that occur in the atmosphere above the IceCube detector. A preliminary offline cross check of IceTop data indicates a background origin for this alert.
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