The imprint of protons on the emission of extended blazar jets

TL;DR

This paper introduces a hadronic extended-jet model for blazars that accounts for proton-driven energy transport and secondary lepton production, aiming to unify the explanation of the entire electromagnetic spectrum.

Contribution

It develops a new kinetic hadronic jet code that highlights the role of protons in energy transport and emission in blazar jets, extending beyond traditional one-zone models.

Findings

Protons can transport energy over larger distances than electrons.

Secondary leptons from pion and Bethe-Heitler processes can dominate leptonic emission.

Parameter studies reveal differences among blazar subclasses.

Abstract

Blazars - active galaxies with the jet pointing at Earth - emit across all electromagnetic wavelengths. The so-called one-zone model has described well both quiescent and flaring states, however it cannot explain the radio emission. In order to self-consistently describe the entire electromagnetic spectrum, extended jet models are necessary. Notably, kinetic descriptions of extended jets can provide the temporal and spatial evolution of the particle species and the full electromagnetic output. Here, we present the initial results of a recently developed hadronic extended-jet code. As protons take much longer than electrons to lose their energy, they can transport energy over much larger distances than electrons and are therefore essential for the energy transport in the jet. Furthermore, protons can inject additional leptons through pion and Bethe-Heitler pair production, which can explain a dominant leptonic radiation signal while still producing neutrinos. We will present a detailed parameter study and provide insights into the different blazar sub-classes.