Multimessenger flare in the quasar PKS 0446+11
Context. The physical mechanisms driving neutrino and electromagnetic flares in blazars remain poorly understood. Aims. We investigate a prominent multimessenger flare in the quasar PKS 0446+11 to identify the processes responsible for its high-energy emission. Methods. We analyzed the IceCube-240105A high-energy neutrino event together with contemporaneous observations in the gamma-ray, X-ray, optical, and radio bands. We modeled the on- and off-flare spectral energy distributions (SEDs) within a single-zone leptohadronic framework. Multi-epoch VLBA observations from the MOJAVE program provide parsec-scale polarization data that complement the multiwavelength light curves. Results. No significant time delay was detected between the neutrino arrival and the flares in different energy bands. This is consistent with an extremely small jet viewing angle below 1 deg, inferred from the parsec-scale polarization structure. The flare can be reproduced by the injection of a proton population and an increase in the Doppler factor from 18 to 24. We also detected an approximately 90 deg rotation of the EVPA in the parsec-scale core during the initial phase of the flare, indicating the emergence of a shock formed by the change in the bulk plasma speed. Conclusions. Our comprehensive multimessenger analysis demonstrates that the extreme beaming and subdegree viewing angle of this distant blazar can account for the observed neutrino and electromagnetic activity. These findings strengthen the case for blazars as efficient accelerators of hadrons and significant contributors to the observed high-energy neutrino flux.
Authors
- A. V. Popkov (ORCID: https://orcid.org/0000-0002-0739-700X)
- A. V. Plavin (ORCID: https://orcid.org/0000-0003-2914-8554)
- Yu. A. Kovalev (ORCID: https://orcid.org/0000-0002-8017-5665)
- A. B. Pushkarev (ORCID: https://orcid.org/0000-0002-9702-2307)
- D. C. Homan (ORCID: https://orcid.org/0000-0002-4431-0890)
- M. L. Lister (ORCID: https://orcid.org/0000-0003-1315-3412)
- Y. Y. Kovalev (ORCID: https://orcid.org/0000-0001-9303-3263)
- А. К. Эркенов (ORCID: https://orcid.org/0000-0002-6086-9299)
- E. Shablovinskaia
- Yu. V. Sotnikova
- V. V. Vlasyuk
- Polina Kivokurtseva (ORCID: https://orcid.org/0000-0003-2955-3904)
- O. I. Spiridonova (ORCID: https://orcid.org/0000-0001-7471-6325)
- P. V. de la Parra (ORCID: https://orcid.org/0000-0001-5957-1412)
- M. F. Aller (ORCID: https://orcid.org/0000-0003-2483-2103)
- S. Troitsky (ORCID: https://orcid.org/0000-0001-6917-6600)
- J. L. Gómez
- A. C. S. Readhead
Institutions
- P.N. Lebedev Physical Institute of the Russian Academy of Sciences (RU)
- California Institute of Technology (US)
- Woodwell Climate Research Center (US)
- Moscow Institute of Physics and Technology (RU)
- University of Concepción (CL)
- Lomonosov Moscow State University (RU)
- Denison University (US)
- Purdue University West Lafayette (US)
- University of Michigan (US)
- Special Astrophysical Observatory (RU)
- Moscow State University (TJ)
- Max Planck Institute for Radio Astronomy (DE)
- Instituto de Astrofísica de Andalucía (ES)
- Crimean Astrophysical Observatory (UA)
Publication Details
- Journal
- Astronomy and Astrophysics
- Published
- 2026-04-03
- DOI
- https://doi.org/10.1051/0004-6361/202558005
- Citations
- 1
- Primary Topic
- Astrophysics and Cosmic Phenomena
- Type
- article
- Field-Weighted Citation Impact
- 18.70
Funders
- National Science Foundation
- National Aeronautics and Space Administration
- John Templeton Foundation
- Gordon and Betty Moore Foundation
- California Institute of Technology
- European Commission
- Ministry of Science and Higher Education of the Russian Federation
- Smithsonian Astrophysical Observatory
- Science Mission Directorate
- Russian Academy of Sciences