The Luminosity Dependence of Uv Absorption in Agn

We describe the results of a survey of the UV absorption properties of the Boroson & Green sample of AGN, which extends from the Seyfert (MV ≃ −21) to the luminous quasar (MV ≃ −27) level. The survey is based mostly on HST archival data available for > ∼ 1/2 of the 87 sample objects. Our main result is that soft X-ray weak quasars (SXWQs, 10 AGN with αox ≤ −2) show the strongest UV absorption at a given luminosity, and their maximum outflow velocity, vmax, is strongly correlated with MV (rS = −0.95). This suggests that vmax is largely set by the luminosity, as expected for radiation-pressure driven outflows. Luminous SXWQs have preferentially low [O III] luminosity, which suggests they are physically distinct from unabsorbed AGN, while non-SXWQs with UV absorption are consistent with being drawn from the unabsorbed AGN population. We also find an indication that vmax/vBLR increases with L/LEdd, as expected for radiation-pressure driven outflows. This relation and the vmax vs. MV relation may indicate that the radiation-pressure force multiplier increases with luminosity, and that the wind launching radius in non-SXWQs is ∼ 10 times larger than in SXWQs. Subject headings: galaxies: active–quasars: absorption lines–X-rays: galaxies