VLT-FORS2 optical imaging and spectroscopy of 9 luminous type 2 AGN at
  0.3<z<0.6: I. Ionized gas nebulae
  We present optical imaging and long slit spectroscopic observations of 9
luminous type 2 AGNs within the redshift range 0.3<z<0.6 based on VLT-FORS2
data. Most objects (6/9) are high luminosity Seyfert 2, and three are type 2
quasars (QSO2), with our sample extending to lower luminosity than previous
works.
  Seven out of nine objects (78%) show morphological evidence for interactions
or mergers in the form of disturbed morphologies and/or peculiar features such
as tidal tails, amorphous halos, or compact emission line knots. The detection
rate of morphological evidence for interaction is consistent with those found
during previous studies of QSO2 at similar z, suggesting that the merger rate
is independent of AGN power at the high end of the AGN luminosity function.
  We find the emission line flux spatial profiles are often dominated by the
often spatially unresolved central source. In addition, all but one of our
sample is associated with much fainter, extended line emission. We find these
extended emission line structures have a variety of origins and ionization
mechanisms: star forming companions, tidal features, or extended ionized
nebulae. AGN related processes dominate the excitation of the nuclear gas.
Stellar photoionization sometimes plays a role in extended structures often
related to mergers/interactions.
