High-resolution Absorption Spectroscopy of Multiphase, High-metallicity Gas Associated with the Luminous

We presentFUSE andHST STIS observations of the absorption-line system near the emission redshift of the radioquiet, X-ray-bright quasar HE 0226 4110 (z 1⁄4 0:495, V 1⁄4 15:2). The spectra cover the rest-frame wavelength range 610–11508, and we detect a wide range of ionization species, including four adjacent stages of oxygen: O iii–vi, which reveal a striking change in gas kinematics with ionization. Examinaton of the O vi kk1031, 1037 doublet profiles reveals no evidence for partial coverage or unresolved saturated structure. O iii is only detected in a narrow feature that is also traced by the H i and C iii lines, suggesting that they arise in the same gas. Absorption at the same velocity is also present in other species (N iv, O iv–vi , S iv, and possibly Ne viii ), but the kinematics differ from the O iii, implying production in separate gaseous phases. The combination of H i, O iii , and C iii information yields an estimate of both the photoionization parameter and the metallicity of the O iii–bearing gas: 1⁄2O/H 1⁄4 þ0:12þ0:16 0:03, logU 1⁄4 2:29þ0:02 0:23. We discuss two possible locations for the gas in this associated absorption-line system: the narrow emission line region of the quasar, and the halo of the quasar host galaxy. An additional narrow (and thus photoionized) component that is only detected inO vi appears 58 km s 1 redward of the O iii–bearing gas with 0:35P logU P 0:02. Additional structure is detected in the associated absorber in the form of two broad components that only appear in moderateto highionization species. Subject headings: quasars: absorption lines — quasars: emission lines — quasars: individual (HE 0226 4110) — ultraviolet: ISM Online material: color figures