Radiation pressure, absorption and AGN feedback in the Chandra Deep
  Fields
  The presence of absorbing gas around the central engine of Active Galactic
Nuclei (AGN) is a common feature of these objects. Recent work has looked at
the effect of the dust component of the gas, and how it enhances radiation
pressure such that dusty gas can have a lower effective Eddington limit than
ionised gas. In this work, we use multi-wavelength data and X-ray spectra from
the 2 Ms exposures of the Chandra Deep Field North and Chandra Deep Field South
surveys, to characterise the AGN in terms of their Eddington ratio and hydrogen
column density. Their distributions are then compared with what is predicted
when considering the coupling between dust and gas. Our final sample consists
of 234 objects from both fields, the largest and deepest sample of AGN for
which this comparison has been made up to date. We find that most of the AGN in
our sample tend to be found at low Eddington ratios (typically between 1e-4 and
1e-1) and high column density (>1e22 cm^-2), with black hole masses between
~1e8 and 1e9 solar masses. Their distribution is in agreement with that
expected from the enhanced radiation pressure model, avoiding the area where we
would predict the presence of outflows. We also investigate how the balance
between AGN radiation pressure and gravitational potential influences the
behaviour of clouds in the galactic bulge, and describe a scenario where an
enhanced radiation pressure can lead to the fundamental plane of black
hole/galaxy scaling relations.
