Abstract AST-9420080 Peterson, Bradley M. . The variability of the broad emission lines in the spectra of active galactic nuclei (AGN) reveals fundamental information about the structure and kinematics of the line-emitting region and about the nature of the central source. Broad emission lines arise in clouds that are photoionized by a central continuum source and respond to variations in the continuum flux with a delay due to light-travel time; the structure and velocity field of the broad-line region can be determined by closely monitoring the response of the emission lines as the region reverberates in response to the continuum variations, making repeated observations of a limited number of sources. This is an ongoing project, as part of the International AGN Watch.
