Inverse Compton Scattering of the Central Source Photons as an X-ray Emission Mechanism on Kiloparsec Scales in PKS 1127-145

TL;DR

This paper investigates whether inverse Compton scattering of photons from the central source explains the X-ray emission in the kiloparsec-scale jet of quasar PKS 1127-145, challenging previous models with new observational data.

Contribution

It demonstrates that a single power-law electron energy distribution can explain radio and X-ray spectral indices, and estimates the jet's viewing angle and relativistic speed.

Findings

Jet viewing angle is about 35 degrees.

Jet has a moderate speed of approximately 0.8c.

Predicted gamma-ray flux is much lower than Fermi-LAT measurements.

Abstract

The beamed inverse Compton/cosmic microwave background model has generally been used for the interpretation of X-ray radiation from kiloparsec-scale jets of the core-dominated quasars. Recent \textit{Fermi}-LAT and \textit{HST} observations have brought this model into question. We examine the assumption that X-rays from the kiloparsec-scale jet of the quasar PKS~1127$-$145 are produced by inverse Compton scattering of the central source emission. In this context, we show that both similarity and distinction between the observed radio and X-ray spectral indices for some of the jet knots can be explained under a single power-law electron energy distribution. We derive that the viewing angle of the kiloparsec-scale jet is about $35^\circ$ and the jet has a moderate relativistic speed of $\approx 0.8c$. The predicted gamma-ray flux of the jet is found to be a few orders of magnitude lower than the minimum flux level measured by \textit{Fermi}-LAT, further supporting our scenario.