Multimessenger Emission Derived from Relativistic Magnetized Jet Dynamics Using a Multizone Framework

Abstract

Relativistic jets from active galactic nuclei (AGN) are highly energetic and emit radiation across a wide range of frequencies. Despite several observational studies, their particle composition still remains a key open question. The detection of high-energy neutrinos from blazar sources such as TXS 0506+056 has highlighted the plausibility of hadronic/leptohadronic models for AGN jets. To understand the origin of high-energy neutrinos from such sources, it is imperative to capture the complex interplay between the jet dynamics, their composition, and the mechanism of particle acceleration and cooling in relativistic jets. In this pilot study, we have coupled a numerical multizone framework for leptohadronic modeling, with 3D relativistic magnetohydrodynamic simulations of AGN jets, including external photon fields. Our framework provides synthetic multiwavelength and neutrino flux by spatially sampling the simulated jet into multiple zones. We investigate the implications of such a framework in exploring the different intrinsic and extrinsic pathways for proton enrichment in jets. Essentially, we find that, for low proton-to-electron number density ratios, producing a substantial jet neutrino flux requires the underlying proton energy distribution to have a relatively flat spectrum with a power-law index of ≃2.0. We further find that while intrinsic shocks triggered by kink instabilities in the jet can accelerate electrons to high energies, they may not be sufficient to produce such flat particle energy distributions for the chosen set of parsec-scale jet parameters. Finally, to produce a significant jet neutrino emission, our simulations suggest the need to consider particle acceleration mechanisms through alternative pathways, either internal or external. © 2026. The Author(s). Published by the American Astronomical Society. Original content from this work may be used under the terms of the https://creativecommons.org/licenses/by/4.0/. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.