Spatially resolved observations of warm ionized gas and feedback in
  local ULIRGs
  We present VLT/VIMOS-IFU emission-line spectroscopy of a volume limited
sample of 18 southern ULIRGs selected with z<0.09 and dec<10. By covering a
wide range of ULIRG types, this dataset provides an important set of templates
for comparison with high-redshift galaxies. We employed an automated Gaussian
line fitting program to decompose the emission line profiles of Halpha, [NII],
[SII], and [OI] into individual components, and chart the Halpha kinematics,
and the ionized gas excitations and densities. 11/18 of our galaxies show
evidence for outflowing warm ionized gas with speeds between 500 and a few 1000
km/s, with the fastest outflows associated with systems that contain an AGN.
Our spatially resolved spectroscopy has allowed us to map the outflows, and in
some cases determine for the first time to which nucleus the wind is
associated. In three of our targets we find line components with widths >2000
km/s over spatially extended regions in both the recombination and forbidden
lines; in two of these three, they are associated with a known Sy2 nucleus.
Eight galaxies have clear rotating gaseous disks, and for these we measure
rotation velocities, virial masses, and calculate Toomre Q parameters. We find
radial gradients in the emission line ratios in a significant number of systems
in our study. We attribute these gradients to changes in ionizing radiation
field strength, most likely due to an increasing contribution of shocks with
radius. We conclude with a detailed discussion of the results for each
individual system, with reference to the existing literature.
  Our observations demonstrate that the complexity of the kinematics and gas
properties in ULIRGs can only be disentangled with high sensitivity, spatially
resolved IFU observations. Many of our targets are ideal candidates for future
high spatial resolution follow-up observations.
