Feeding and Feedback in the Powerful Radio Galaxy 3C 120

Abstract

We present a spectral analysis of a 200 ks observation of the broad-line radio galaxy 3C 120, performed with the high-energy transmission grating spectrometer on board the Chandra X-ray Observatory . We find (i) a neutral absorption component intrinsic to the source with a column density of cm −2 ; (ii) no evidence for a warm absorber (WA) with an upper limit on the column density of just cm −2 , assuming the typical ionization parameter log ξ  ≃ 2.5 erg s −1  cm; the WA may instead be replaced by (iii) a hot emitting gas with a temperature kT  ≃ 0.7 keV observed as soft X-ray emission from ionized Fe L-shell lines, which may originate from a kiloparsec-scale shocked bubble inflated by the active galactic nucleus (AGN) wind or jet with a shock velocity of about 1000 km s −1 determined by the emission line width; (iv) a neutral Fe K α line and accompanying emission lines indicative of a Compton-thick cold reflector with a low reflection fraction R  ≃ 0.2, suggesting a large opening angle of the torus; (v) a highly ionized Fe xxv emission feature indicative of photoionized gas with an ionization parameter log erg s −1  cm and a column density of cm −2 localized within ∼2 pc from the X-ray source; and (vi) possible signatures of a highly ionized disk wind. Together with previous evidence for intense molecular line emission, these results indicate that 3C 120 is likely a late-state merger undergoing strong AGN feedback.