A Chandra study of the multicomponent X-ray emission from the X-shaped radio galaxy 3C 403

RP Kraft*, MJ Hardcastle, DM Worrall, SS Murray

*Corresponding author for this work

Research output: Contribution to journalArticle (Academic Journal)peer-review

77 Citations (Scopus)


We present results from a 49.4 ks Chandra ACIS-S observation of the nearby (z = 0.059) X-shaped FR type II (FR II) radio galaxy 3C 403. This is the first Chandra observation of an X-shaped radio galaxy, and one of the goals of this pioneering study is to determine the relationship between the X-ray-emitting gas and the X-shaped radio morphology. We find that the X-ray isophotes of the hot gas within similar to 3.'' 5 of the central galaxy are highly elliptical (eccentricity similar to 0.57) and coaligned with the elliptical optical isophotes. This supports the hypothesis that X-shaped radio sources are created by propagation of jets through asymmetric density distributions. Within large uncertainties, there is no evidence that the lobes or wings are overpressurized relative to the interstellar medium (ISM), supporting the scenario in which the wings are the result of strong backflows of material from the jet head and subsequent buoyant evolution. We have detected X-ray emission from several of the radio knots to the east of the active nucleus and diffuse emission from the radio lobe to the west. The X-ray emission from the eastern knots cannot be explained by an inverse Compton model unless they are far from equipartition. Using archival Hubble Space Telescope (HST) data, optical emission is detected from two knots, and the radio/optical/X-ray spectra are well fitted by simple synchrotron models. This is one of the strongest examples to date of X-ray synchrotron emission from multiple knots in the jet of an FR II radio galaxy. X-ray emission is also detected from the radio wings at a flux consistent with inverse Compton scattering of cosmic microwave background (CMB) photons from relativistic electrons if the wings are near equipartition. The nuclear spectrum is well described by a multicomponent model that includes a heavily absorbed power law (N-H similar to 4 x 10(23) cm(-2)) and a bright (EW similar to 244 eV), broadened Fe line. A second, less absorbed, power-law component, likely representing unresolved emission from a parsec-scale jet, is also required.

Original languageEnglish
Pages (from-to)149-159
Number of pages11
JournalAstrophysical Journal
Issue number1
Publication statusPublished - 20 Mar 2005


  • galaxies : active
  • galaxies : individual (3C 403)
  • galaxies : ISM
  • X-rays : galaxies
  • 3.6 CM
  • JET
  • GAS
  • Z-LESS-THAN-0.3

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