FSRQ OQ 334: Upper limits from a neutrino search with IceCube
ATel #17835; Yuhua Yao (University of WisconsinâMadison), Justin Vandenbroucke (University of WisconsinâMadison) for the IceCube Collaboration
on 6 Jun 2026; 21:42 UT
Credential Certification: Justin Vandenbroucke (justin.vandenbroucke@wisc.edu)
Subjects: Neutrinos, Blazar
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 flat-spectrum radio quasar (FSRQ) OQ 334 (B2 1420+326). This FSRQ was recently found to be flaring brightly in the radio (ATel # 17745), NIR (ATel #17792), optical (ATel #17795, ATel #17782), GeV (ATel #17790, ATel #17821), and >100 GeV (ATel #17802) electromagnetic bands. We searched in a time range of 30 days (2026-05-05 00:00:00.00 UTC to 2026-06-04 00:00:00.00 UTC), during which IceCube was collecting good quality data.
For this search, we report a p-value of 0.155 with respect to an atmospheric background-only hypothesis. We accordingly derive a time-integrated muon-neutrino flux upper limit for this source of E^2 dN/dE = 6.6e-2 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 are between approximately 700 GeV and 500 TeV.
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)
