BASS XXX: Distribution Functions of DR2 Eddington-ratios, Black Hole
  Masses, and X-ray Luminosities
  We determine the low-redshift X-ray luminosity function (XLF), active black
hole mass function (BHMF), and Eddington-ratio distribution function (ERDF) for
both unobscured (Type 1) and obscured (Type 2) active galactic nuclei (AGN)
using the unprecedented spectroscopic completeness of the BAT AGN Spectroscopic
Survey (BASS) data release 2. In addition to a straightforward 1/Vmax approach,
we also compute the intrinsic distributions, accounting for sample truncation
by employing a forward modeling approach to recover the observed BHMF and ERDF.
As previous BHMFs and ERDFs have been robustly determined only for samples of
bright, broad-line (Type 1) AGNs and/or quasars, ours is the first directly
observationally constrained BHMF and ERDF of Type 2 AGN. We find that after
accounting for all observational biases, the intrinsic ERDF of Type 2 AGN is
significantly skewed towards lower Eddington ratios than the intrinsic ERDF of
Type 1 AGN. This result supports the radiation-regulated unification scenario,
in which radiation pressure dictates the geometry of the dusty obscuring
structure around an AGN. Calculating the ERDFs in two separate mass bins, we
verify that the derived shape is consistent, validating the assumption that the
ERDF (shape) is mass independent. We report the local AGN duty cycle as a
function of mass and Eddington ratio, by comparing the BASS active BHMF with
the local mass function for all SMBH. We also present the log N-log S of
Swift-BAT 70-month sources.
