2010ApJ...723L.228F

We extend our modeling of the ionization structure of magnetohydrodynamic (MHD) accretion-disk winds, previously applied to Seyfert galaxies, to a population of quasi-stellar objects (QSOs) of much lower X-ray-to-UV flux ratios, i.e., smaller α_oxindex, motivated by UV/X-ray ionized absorbers with extremely high outflow velocities in UV-luminous QSOs. We demonstrate that magnetically driven winds ionized by a spectrum with α_ox≃ -2 can produce the charge states responsible for C IV and Fe XXV/Fe XXVI absorption in wind regions with corresponding maximum velocities of v(C IV) ≲0.1c and v(Fe XXV) ≲ 0.6c (where c is the speed of light) and column densities N_H∼ 10²³-10²⁴/cm2, in general agreement with observations. In contrast to the conventional radiation-driven wind models, high-velocity flows are always present in our MHD-driven winds but manifest in the absorption spectra only for α_ox≲ -2, as larger α_ox values ionize the wind completely out to radii too large to demonstrate the presence of these high velocities. We thus predict increasing velocities of these ionized absorbers with decreasing (steeper) α_ox, a quantity that emerges as the defining parameter in the kinematics of the active galactic nucleus UV/X-ray absorbers.