The 300 kpc long X-ray jet in PKS 1127-145, z = 1.18 quasar: Constraining X-ray emission models

Aneta Siemiginowska, ŁUkasz Stawarz, C. C. Cheung, D. E. Harris, Marek Sikora, Thomas L. Aldcroft, Jill Bechtold

Research output: Contribution to journalArticlepeer-review

63 Scopus citations


We present a ∼100 ks Chandra X-ray observation and new VLA radio data of the large-scale, 300 kpc long X-ray jet in PKS 1127-145, a radio-loud quasar at redshiftz = 1.18. With this deep X-ray observation we now clearly discern the complex X-ray jet morphology and see substructure within the knots. The X-ray and radio jet intensity profiles are seen to be 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. The jet X-ray surface brightness gradually decreases by an order of magnitude going out from the core. The new X-ray data contain sufficient counts for spectral analysis of the key jet features. The X-ray energy index of the inner jet is relatively flat with αX = 0.66 ± 0.15 and steep in the outer jet with αX = 1.0 ± 0.2. We discuss the constraints implied by the new 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.

Original languageEnglish (US)
Pages (from-to)145-158
Number of pages14
JournalAstrophysical Journal
Issue number1 I
StatePublished - Mar 1 2007


  • Galaxies: jets
  • Quasars: individual (PKS 1127 -145)
  • X-rays: galaxies

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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