AChandraStudy of the Multicomponent X‐Ray Emission from the X‐shaped Radio Galaxy 3C 403

Abstract

We present results from a 49.4 ks Chandra ACIS-S observation of the nearby (z ¼ 0:059) X-shaped FR type II (FR II)radiogalaxy3C403.ThisisthefirstChandraobservationofanX-shapedradiogalaxy,andoneofthegoals 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 � 3B5 of the central galaxy are highly elliptical (eccentricity � 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 emissionfrommultipleknotsinthejetofanFRIIradiogalaxy.X-rayemissionisalsodetectedfromtheradiowings 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 (NH � 4 ;10 23 cm � 2 ) and a bright (EW � 244 eV), broadened Fe line. A second, less absorbed, power-law component, likely representing unresolved emission from a parsec-scale jet, is also required. Subject headings: galaxies: active — galaxies: individual (3C 403) — galaxies: ISM — X-rays: galaxies