The Intrinsic Quasar Luminosity Function: Accounting for Accretion Disk
  Anisotropy
  Quasar luminosity functions are a fundamental probe of the growth and
evolution of supermassive black holes. Measuring the intrinsic luminosity
function is difficult in practice, due to a multitude of observational and
systematic effects. As sample sizes increase and measurement errors drop,
characterizing the systematic effects is becoming more important. It is well
known that the continuum emission from the accretion disk of quasars is
anisotropic --- in part due to its disk-like structure --- but current
luminosity function calculations effectively assume isotropy over the range of
unobscured lines of sight. Here, we provide the first steps in characterizing
the effect of random quasar orientations and simple models of anisotropy on
observed luminosity functions. We find that the effect of orientation is not
insignificant and exceeds other potential corrections such as those from
gravitational lensing of foreground structures. We argue that current
observational constraints may overestimate the intrinsic luminosity function by
as much as a factor of ~2 on the bright end. This has implications for models
of quasars and their role in the Universe, such as quasars' contribution to
cosmological backgrounds.
