Study suggests blazar population may be source of record-setting neutrino

The Story

On February 13, 2023, the most energetic neutrino ever observed was detected by the KM3NeT/ARCA observatory off the coast of Sicily. A new study published in the Journal of Cosmology and Astroparticle Physics proposes that the particle, which carried about 220 PeV of energy, may have originated from a population of blazars — supermassive black holes with jets pointing toward Earth. Researchers caution that more data from the still-under-construction KM3NeT detector are needed to confirm the explanation.

Key Facts

• The neutrino was detected on February 13, 2023, by KM3NeT/ARCA, a neutrino observatory located deep off the coast of Sicily.
• The particle carried an estimated energy of around 220 PeV, more than ten times greater than previously detected high-energy neutrinos.
• At the time of detection, only 21 detection lines were operational, representing about 10% of the observatory’s planned final size.
• According to a new study in the Journal of Cosmology and Astroparticle Physics, the neutrino may have originated from blazars, active galactic nuclei that shoot jets of plasma toward Earth.
• Researchers used an open source simulation tool called AM3 to model realistic blazar populations.
• The study combined observations from KM3NeT/ARCA, the IceCube Neutrino Observatory, and NASA’s Fermi Gamma-ray Space Telescope.
• No electromagnetic counterpart (e.g., radio, X-ray, gamma rays) was found at the same time and location as the neutrino detection.
• The lack of a counterpart led researchers to consider that the neutrino came from a diffuse flux produced by many blazars rather than a single source.
• The blazar model matched constraints from the rarity of such events and from gamma-ray background measurements by Fermi.
• Meriem Bendahman, a researcher at INFN Naples and member of the KM3NeT collaboration, is among the authors of the study.

Conflicting Reports

No conflicting reports identified in the source article.

Still Unclear

Whether the blazar explanation is correct remains unconfirmed; more data from the full KM3NeT detector are needed to perform stronger statistical analyses.

Misconceptions

No widespread misconceptions addressed in the source article.

Key Figures

• Meriem Bendahman — Researcher at INFN Naples and a member of the KM3NeT collaboration

Sources

• https://www.sciencedaily.com/releases/2026/05/260523103912.htm — Primary Source