The Viewing Angles of Broad Absorption Line Versus Unabsorbed Quasars
  It was recently shown that there is a significant difference in the radio
spectral index distributions of broad absorption line (BAL) quasars and
unabsorbed quasars, with an overabundance of BAL quasars with steeper radio
spectra. This result suggests that source orientation does play into the
presence or absence of BAL features. In this paper we provide more quantitative
analysis of this result based on Monte-Carlo simulations. While the
relationship between viewing angle and spectral index does indeed contain a lot
of scatter, the spectral index distributions are different enough to overcome
that intrinsic variation. Utilizing two different models of the relationship
between spectral index and viewing angle, the simulations indicate that the
difference in spectral index distributions can be explained by allowing BAL
quasar viewing angles to extend about 10 degrees farther from the radio jet
axis than non-BAL sources, though both can be seen at small angles. These
results show that orientation cannot be the only factor determining whether BAL
features are present, but it does play a role.
