Disc Winds and Line-Width Distributions in Active Galactic Nuclei

We study Active Galactic Nucleus (AGN) emission-line profiles by combining an improved version of the accretion disc-wind model of Murray & Chiang with the magnetohydrodynamic model of Emmering et al. We consider central objects with different masses and/or luminosities. We show how the shape, broadening and shift of the C IV line depend not only on the viewing angle to the object but also on the wind launching angle, especially for small launching angles. We have compared the dispersions in our model C IV line-width distributions to observational upper limits on that dispersion, considering both smooth and clumpy torus models. Following Fine et al., we transform that scatter in the profile line-widths into a constraint on the torus geometry. We show how the half-opening angle of the obscuring structure depends on the mass and luminosity of the central object.