Lepto-hadronic modeling of blazars associated with well-reconstructed high-energy neutrino events
Abstract
The association of active galactic nuclei (AGN) with high-energy neutrinos has been studied through population and individual source analyzes, but whether these associations reflect physical processes or chance coincidences remains open. Blazars, AGN with relativistic jets aligned with the line of sight, spatially consistent with IceCube high-energy events, offer a natural framework to address this question. Combining multifrequency observations with physically motivated emission models allows us to assess whether these sources can plausibly account for the detected neutrinos. We study six blazars with single gamma-ray counterparts to well-reconstructed IceCAT-1 high-energy events, accounting for the improved localization expected from IceCAT-2, and compile their multifrequency spectral energy distributions (SEDs). We model these sources within a lepto-hadronic framework, exploring their parameter space to reproduce the observed emission while favoring solutions that maximize neutrino production. The SEDs can be reproduced with compact emission regions close to the broad-line region with moderate Doppler factors. The emission is generally leptonic-dominated, with subdominant contributions from hadronic cascades, except for one source where the gamma-rays are hadronic-dominated. For four, the energy density of the relativistic particles is close to equipartition with the magnetic field. The predicted neutrino detection rates reach up to 5x10−2 per year, mostly compatible with one observed IceCube event under Poisson statistics. While these blazars are unlikely to significantly contribute to the diffuse neutrino flux, their properties are consistent with being possible counterparts to individual neutrino events, driven by contributions of external photon fields to the hadronic interaction rate, even for sources where these fields have previously been considered as non-significant.
Related
- Hadronic origin of gamma rays and neutrinos from blazars: Multi-messenger implications and observational constraints
- An Evolving Leptonic Jet Model for Delayed Radio Flares in Neutrino Blazars
- KM3NeT/ARCA stacking search for high-energy neutrino point sources: the case of ultra-luminous infrared galaxies and blazars
- Self-consistent modeling of energy-dependent synchrotron polarization in blazars with application to Mrk 421
- Multi-wavelength Behaviour and Lepto-hadronic Modeling of PKS 0215+015 Around the Epoch of IceCube-220225A
BibTeX
@misc{pfeiffer2026leptohadronic,
title = {{Lepto-hadronic modeling of blazars associated with well-reconstructed high-energy neutrino events}},
author = {Leonard Pfeiffer and Margot Boughelilba and Simone Garrappa and Sara Buson and Massimiliano Lincetto and Annette Bremer},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.19477},
eprint = {2609.19477},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.19477},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Lepto-hadronic modeling of blazars associated with well-reconstructed high-energy neutrino events
AU - Leonard Pfeiffer
AU - Margot Boughelilba
AU - Simone Garrappa
AU - Sara Buson
AU - Massimiliano Lincetto
AU - Annette Bremer
PY - 2026
DA - 2026/09/16
PB - arXiv
DO - 10.48550/arxiv.2609.19477
UR - https://arxiv.org/abs/2609.19477
AB - The association of active galactic nuclei (AGN) with high-energy neutrinos has been studied through population and individual source analyzes, but whether these associations reflect physical processes or chance coincidences remains open. Blazars, AGN with relativistic jets aligned with the line of sight, spatially consistent with IceCube high-energy events, offer a natural framework to address this question. Combining multifrequency observations with physically motivated emission models allows us to assess whether these sources can plausibly account for the detected neutrinos. We study six blazars with single gamma-ray counterparts to well-reconstructed IceCAT-1 high-energy events, accounting for the improved localization expected from IceCAT-2, and compile their multifrequency spectral energy distributions (SEDs). We model these sources within a lepto-hadronic framework, exploring their parameter space to reproduce the observed emission while favoring solutions that maximize neutrino production. The SEDs can be reproduced with compact emission regions close to the broad-line region with moderate Doppler factors. The emission is generally leptonic-dominated, with subdominant contributions from hadronic cascades, except for one source where the gamma-rays are hadronic-dominated. For four, the energy density of the relativistic particles is close to equipartition with the magnetic field. The predicted neutrino detection rates reach up to 5x10^−2 per year, mostly compatible with one observed IceCube event under Poisson statistics. While these blazars are unlikely to significantly contribute to the diffuse neutrino flux, their properties are consistent with being possible counterparts to individual neutrino events, driven by contributions of external photon fields to the hadronic interaction rate, even for sources where these fields have previously been considered as non-significant.
ER -