[O II] emission, eigenvector 1, and orientation in radio-quiet quasars

We present supportive evidence that the Boroson & Green eigenvector 1 is no t driven by source orientation and further that both [O III] lambda 5007 an d [O II] lambda 3727 are isotropically emitted in the radio-quiet sample of bright quasar survey (BQS) quasars, contrary to results found for radio-lo ud active galactic nuclei (AGNs). Studies of optical emission lines in quas ars have revealed a striking set of correlations between various emission-l ine properties, known as the Boroson & Green eigenvector 1. Until recently it was generally accepted that eigenvector 1 does not depend on orientation , as it strongly correlates with [O III] lambda 5007 emission, thought to b e an isotropic property. However, recent studies of radio-loud AGNs have qu estioned the isotropy of [O III] emission and concluded that [O III] lambda 3727 emission is isotropic. In this paper we investigate the relation betw een eigenvector 1 and [O III] emission in radio-quiet BQS quasars and readd ress the issue of orientation as the driver of eigenvector 1. We account fo r the small blue bump present at [O II] wavelengths and subtract Fe II emis sion that contaminates [O III] emission. We find significant correlations b etween eigenvector 1 and orientation-independent [O II] emission, which imp lies that orientation does not drive eigenvector 1. The luminosities and eq uivalent widths of [O III] and [O II] correlate with one another, and the r ange in luminosities and equivalent widths is similar. This suggests that o ur radio-quiet BQS quasar sample is largely free of orientation-dependent o bscuration and/or ionization effects. We conclude that neither the [O III] emission nor the [O II]/[O III] ratio are dependent on orientation in radio -quiet quasars, contrary to recent results found for radio-loud quasars.