OP 313 May 2025 gamma-ray flare: Upper limits from a neutrino search with IceCube
ATel #17202; Sam Hori (University of Wisconsin-Madison), Anna Franckowiak (Ruhr-University Bochum), Justin Vandenbroucke (University of Wisconsin-Madison), Marcos Santander (University of Alabama-Tuscaloosa)
on 23 May 2025; 22:42 UT
Credential Certification: Justin Vandenbroucke (justin.vandenbroucke@wisc.edu)
The IceCube Collaboration (http://icecube.wisc.edu/) reports:
IceCube has performed a search for track-like muon neutrino events arriving from the direction of the blazar OP 313, a flat-spectrum radio quasar also known as B2 1308+32. The search was carried out for a time window of 22 days (2025-04-30 12:00:00.00 UTC to 2025-05-22 12:00:00.00 UTC) while the source was flaring in GeV gamma rays, as reported by Fermi-LAT (ATel 17167). During this period IceCube was collecting good quality data. We find that these data are consistent with atmospheric background expectations, with a p-value of 1. We accordingly derive a time-integrated muon-neutrino flux upper limit for this source of E^2 dN/ dE = 0.066 GeV cm^-2 at 90% CL, under the assumption of an E^-2 power law. 90% of events IceCube would detect from a source at this declination with an E^-2 spectrum have energies in the approximate range 700 GeV to 500 TeV.
IceCube has previously performed real-time follow-up searches for neutrino emission associated with gamma-ray flares from this source in June 2022 (ATel 15492) and from December 2024 to February 2025 (ATel 17016).
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.
[1] IceCube Collaboration, R. Abbasi et al., ApJ 910 4 (2021)
