Emission-line Outflows from the Circumnuclear to Circumgalactic Scales in a Partially Obscured Quasar

Abstract

Abstract We present a detailed analysis of the rest-frame UV and optical emission-line spectrum of the partially obscured quasar J121704.70+023417.1 (hereafter J1217+0234). Here the obscuring material, very likely the dusty torus invoked by the AGN unification models, acts as a natural coronagraph, which greatly suppresses both the continuum and broad-line emission in the UV and enables a clear detection of three emission-line components at and beyond the dusty torus scale: (1) The component, with a blueshift of v ≈ 1200 km s−1 and a line width of FWHM ≈ 2600 km s−1, shows exceptionally large intensity ratios, such as N v/Lyα ≈ 2.3 and O vi/Lyα ≈ 1.4, indicating that the emitting gas is highly ionized and has a very high density up to n H ∼ 1013 cm−3, possibly associated with the dusty torus. (2) The largely unshifted narrow-line component, with FWHM ≈ 510 km s−1, is completely absent in all UV lines but Lyα and is significantly detected in the forbidden lines of [O iii], [O ii], and [Ne iii] in the optical, implying massive low-density (n H ∼ 102 cm−3) gas ∼40 kpc from the galactic center. (3) The intermediate component is only detected in [O iii] with a blueshift and line width between (1) and (2), which might bridge the gases from the circumnuclear to the circumgalactic scales. Follow-up observations with high spatial resolution and high sensitivity are needed to confirm the speculation and are helpful to reveal outflows at multiscales in J1217+0234.