Integral Field Spectroscopy of the circumnuclear region of the Radio
  Galaxy Pictor A
  We present optical integral field spectroscopy of the inner $2.5 \times 3.4$
kpc$^2$ of the broad-line radio galaxy Pictor A, at a spatial resolution of
$\approx 400$ pc. Line emission is observed over the whole field-of-view, being
strongest at the nucleus and in an elongated linear feature (ELF) crossing the
nucleus from the south-west to the north-east along PA $\sim 70^\circ$.
Although the broad double-peaked H$\alpha$ line and the [OI]6300/H$\alpha$ and
[SII]6717+31/H$\alpha$ ratios are typical of AGNs, the [NII]6584/H$\alpha$
ratio (0.15 - 0.25) is unusually low. We suggest that this is due to the
unusually low metallicity of the gas. Centroid velocity maps show mostly
blueshifts to the south and redshifts to the north of the nucleus, but the
velocity field is not well fitted by a rotation model. Velocity dispersions are
low (< 100 km s$^{-1}$) along the ELF, ruling out a jet-cloud interaction as
the origin of this structure. The ELF shows both blueshifts and redshifts in
channel maps, suggesting that it is close to the plane of the sky. The ELF is
evidently photoionized by the AGN, but its kinematics and inferred low
metallicity suggest that this structure may have originated in a past merger
event with another galaxy. We suggest that the gas acquired in this interaction
may be feeding the ELF.
