The Complex Circumnuclear Environment of the Broad-Line Radio Galaxy 3C 390.3 Revealed by Chandra HETG

We present the first high spectral resolution X-ray observation of the broad-line radio galaxy 3C 390.3 obtained with the high-energy transmission grating spectrometer on board the Chandra X-ray Observatory. The spectrum shows complex emission and absorption features in both the soft X-rays and Fe K band. We detect emission and absorption lines in the energy range E = 700-1000 eV associated with ionized Fe L transitions (Fe XVIIXX). An emission line at the energy of E approximately equal to 6.4 keV consistent with the Fe K alpha is also observed. Our best-fit model requires at least three different components: (i) a hot emission component likely associated with the hot interstellar medium in this elliptical galaxy with temperature kT = 0.5 +/- 0.1 keV; (ii) a warm absorber with ionization parameter log Epislon = 2.3 +/- 0.5 erg s(exp 1) cm, column density logN(sub H) = 20.7 +/- 0.1 cm(exp -2), and outflow velocity v(sub out) less than 150 km s(exp -1); and (iii) a lowly ionized reflection component in the Fe K band likely associated with the optical broad-line region or the outer accretion disk. These evidences suggest the possibility that we are looking directly down the ionization cone of this active galaxy and that the central X-ray source only photoionizes along the unobscured cone. This is overall consistent with the angle-dependent unified picture of active galactic nuclei.