Similarity of ionized gas nebulae around unobscured and obscured quasars
  Quasar feedback is suspected to play a key role in the evolution of massive
galaxies, by removing or reheating gas in quasar host galaxies and thus
limiting the amount of star formation. In this paper we continue our
investigation of quasar-driven winds on galaxy-wide scales. We conduct Gemini
Integral Field Unit spectroscopy of a sample of luminous unobscured (type 1)
quasars, to determine the morphology and kinematics of ionized gas around these
objects, predominantly via observations of the [O III]5007 emission line. We
find that ionized gas nebulae extend out to ~13 kpc from the quasar, that they
are smooth and round, and that their kinematics are inconsistent with gas in
dynamical equilibrium with the host galaxy. The observed morphological and
kinematic properties are strikingly similar to those of ionized gas around
obscured (type 2) quasars with matched [O III] luminosity, with marginal
evidence that nebulae around unobscured quasars are slightly more compact.
Therefore in samples of obscured and unobscured quasars carefully matched in [O
III] luminosity we find support for the standard geometry-based unification
model of active galactic nuclei, in that the intrinsic properties of quasars,
of their hosts and of their ionized gas appear to be very similar. Given the
apparent ubiquity of extended ionized regions, we are forced to conclude that
either the quasar is at least partially illuminating pre-existing gas or that
both samples of quasars are seen during advanced stages of quasar feedback. In
the latter case, we may be biased by our [O III]-based selection against
quasars in the early "blow-out" phase, for example due to dust obscuration.
