The Case of the 300 kpc Long X-ray Jet in PKS 1127-145 at z=1.18

TL;DR

This study analyzes the 300 kpc X-ray jet in PKS 1127-145, revealing complex morphology and spectral variations, and suggests a multi-component emission model involving a jet core and sheath, with implications for jet activity.

Contribution

It provides detailed X-ray and radio observations of a large quasar jet, demonstrating the need for multi-component models to explain broadband emission.

Findings

X-ray brightness decreases with distance from the core

Inner jet has a flatter X-ray spectrum than outer regions

X-ray and radio emissions peak at different jet locations

Abstract

The complex X-ray morphology of the 300 kpc long X-ray jet in PKS1127-145 (z=1.18 quasar) is clearly discerned in a ~100 ksec Chandra observation. The jet X-ray surface brightness gradually decreases by an order of magnitude going out from the core. The X-ray spectrum of the inner jet is relatively flat with alpha_X=0.66+/-0.15 and steep in the outer jet with alpha_X=1.0+/-0.2. The X-ray and radio jet intensity profiles are strikingly different, with the radio emission peaking strongly at the two outer knots while the X-ray emission is strongest in the inner jet region. We discuss the constraints implied by these data on the X-ray emission models and conclude that ``one-zone'' models fail and that at least a two-component model is needed to explain the jet's broadband emission. We propose that the X-ray emission originates in the jet proper while the bulk of the radio emission comes from a surrounding jet sheath. We also consider intermittent jet activity as a possible cause of the observed jet morphology.