MODELING HIGH-VELOCITY QSO ABSORBERS WITH PHOTOIONIZED MAGNETOHYDRODYNAMIC DISK WINDS

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 alpha(ox) index, 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 alpha(ox) similar or equal to -2 can produce the charge states responsible for C IV and Fe XXV/Fe XXVI absorption in wind regions with corresponding maximum velocities of nu(C IV) less than or similar to 0.1c and nu(Fe xxv) less than or similar to 0.6c (where c is the speed of light) and column densities N(H) similar to 10(23)-10(24) cm(-2), 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 alpha(ox) less than or similar to -2, as larger alpha(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) aox, a quantity that emerges as the defining parameter in the kinematics of the active galactic nucleus UV/X-ray absorbers.