REVERBERATION MAPPING AND THE DISK-WIND MODEL OF THE BROAD-LINE REGION

Using the disk-wind model of Murray et al., we calculate line profiles and frequency-resolved response functions for broad-line emission fro m the surface of an accretion disk in an active galactic nucleus in th e presence of a radiatively driven wind. We find that the combined eff ects of the shears in the wind and in the disk itself produce anisotro pic line emission, which solves several well-known problems connected with disk models of the broad-line region. In particular, the broadeni ng of resonance lines such as C IV, Ly alpha, and N V can be attribute d to orbital motion of the disk gas at radii as close as similar to 10 (16) cm in Seyferts, without requiring unrealistically large emission regions in order to produce single-peaked profiles. Furthermore, the a nisotropy of the line emission results in frequency-dependent response functions which are no longer red-blue symmetric, so that the time de lays inferred for the various red and blue components of the line agre e qualitatively with recent reverberation mapping observations of NGC 5548.