QSO emission line profiles from Keplerian cloud ensembles

Abstract

Quasar broad emission line profile calculations are presented for spherically symmetric ensembles of flattened broad-line clouds in elliptical Keplerian orbits. In general, it is found that high eccentricity monoenergetic orbital ensembles tend to provide more acceptable profiles than low eccentricity monoenergetic ensembles. The investigation of elliptical cloud orbits evolving under the influence of Poynting-Robertson drag or drag from an intercloud media shows that acceptable line profiles naturally result from the decay of initially monoenergetic, high eccentricity ensembles independent of the assumed emission anisotropy, provided the drag is not so great as to cause the immediate capture or disruption of the clouds.