The Velocity Distribution of Quasar/AGN Broad Emission Line Clouds

The authors deconvolve the effects of geometric projection from the observed broad emission line profiles from a number of active galaxies to reveal the intrinsic brightness versus velocity function of the emission-line clouds. The only free parameters in the analysis are (1) the macroscopic symmetry of the emission line region (macrostructure) and (2) the emission anisotropy of individual clouds (microstructure). The authors conclude that the preponderance of evidence indicates that the broad-line emission arises from gas with preferred absolute velocity relative to line center.