A Photo-Hadronic Model of the Large Scale Jets of 3C 273 and PKS 1136-135

TL;DR

This paper extends a photo-hadronic model to explain X-ray emissions in large-scale jets of quasars 3C 273 and PKS 1136-135, incorporating AGN photon effects and suggesting beaming and Doppler shifts can reduce the required proton power.

Contribution

It introduces the first inclusion of AGN photon effects in the hadronic model for jet X-ray emission and explores conditions for near-Eddington proton power.

Findings

Model can explain X-ray flux with AGN photon contribution.

Proton power required is highly super-Eddington without photon beaming.

Enhanced AGN photon density allows near-Eddington proton power.

Abstract

X-ray bright knots of kpc-scale jets of several radio loud quasars have been an actively discussed issue. Among various models to explain observations, synchrotron radiation from the electron population different from radio to IR emitting electrons is promising. However, the origin of this electron population has been debated. Recently, we proposed that this electron population is produced by proton-photon collisions (mainly, Bethe-Heitler process), and we applied this model to PKS 0637-752. We found that this model works if the proton power is by an order of magnitude larger than the Eddington power. In this paper we apply this model to the X-ray emission in the knots of 3C 273 and PKS 1136-135. The target photons for electron-positron pair production are supplied by synchrotron radiation at radio-IR by primary electrons and by the active galactic nucleus (AGN) core as well as cosmic microwave background (CMB) radiation. The effects of the AGN photons are included for the first time in the hadronic model. Though the observed X-ray flux is obtained with the contribution of the AGN photons, the required proton power turns out to be highly super-Eddington. However, we find that our model works for a nearly Eddington proton power, if the photon density of the AGN is enhanced. This can occur if the AGN photons are more beamed toward the X-ray knots than toward our line of sight and the AGN photon frequency is shifted by the Doppler effect.