IceCube-250309A - IceCube observation of a high-energy neutrino candidate track-like event coincident with GRB 250309B
ATel #17070; Anna Franckowiak (Ruhr-University Bochum), Lu Lu (University of Wisconsin_Madison), Giacomo Sommani (Ruhr-University Bochum), Tianlu Yuan (University of Wisconsin-Madison), Angela Zegarelli (Ruhr-University Bochum), Justin Vandenbroucke (University of Wisconsin-Madison), Marcos Santander (University of Alabama)
on 9 Mar 2025; 14:18 UT
Credential Certification: Anna Franckowiak (anna.franckowiak@desy.de)
Subjects: Neutrinos, Gamma-Ray Burst
The IceCube Collaboration (http://icecube.wisc.edu/) reports:
On 2025-03-09 at 07:36:04.75 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. This alert has an estimated false alarm rate of 0.18 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/140626_1288692.amon), more sophisticated reconstruction algorithms have been applied offline, with the direction refined to:
Date: 2025-03-09
Time: 07:36:04.75 UT
RA: 211.07 (+0.31 -0.30 deg 90% PSF containment) J2000
Dec: -10.73 (+0.26 -0.30 deg 90% PSF containment) J2000
The inferred neutrino energy of this alert is ~4 PeV, making it the fourth-highest energy known detection by IceCube over the past decade.
The alert is in spatial coincidence with the Fermi GRB250309B (Fermi-GBM trigger 763198715 at 07:38:30.66 on 09 March 2025; https://gcn.gsfc.nasa.gov/other/763198715.fermi) with a time 145.91 seconds before the GBM trigger. The angular distance to the most updated reconstruction released by the GBM team, which has a 1 sigma statistical error of 1.60 deg, is 0.77 degrees. An alternative algorithm results in a shifted direction (https://gcn.nasa.gov/circulars/39629) with an angular distance from the best fit neutrino direction of 3.18 degrees and has a 1 sigma statistical error of 1.3 degree and a systematic error of 1 degree.
We strongly encourage follow-up observations of the neutrino region of interest and the uncertainty region of GRB250309B.
No known gamma-ray sources listed in the Fermi 4FGL-DR4 or 3FHL catalogs are located within the 90% uncertainty region 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 roc@icecube.wisc.edu
