Orientation effects in QSO spectra

Abstract

The consequences of anisotropic continuum emission for the equivalent-width distribution of QSOs are investigated and compared with observations from a large QSO survey. Isotropic line emission is assumed, and a variety of continuum anisotropy models are investigated. Far fewer high equivalent width QSOs are observed than most models predict. Both thick and thin accretion disks are ruled out, unless their radiation is reprocessed into a more isotropic angular distribution, or an obscuring torus conceals the broad-line region of nearly edge-on QSOs.