Gas rotation, shocks and outflow within the inner 3 kpc of the radio
  galaxy 3C 33
  We present optical integral field spectroscopy $-$ obtained with the Gemini
Multi-Object Spectrograph $-$ of the inner $4.0 \times 5.8$ kpc$^2$ of the
narrow line radio galaxy 3C 33 at a spatial resolution of 0.58 kpc. The gas
emission shows three brightest structures: a strong knot of nuclear emission
and two other knots at $\approx 1.4$ kpc south-west and north-east of the
nucleus along the ionization axis. We detect two kinematic components in the
emission lines profiles, with a "broader component" (with velocity dispersion
$\sigma > 150$ km s$^{-1}$) being dominant within a $\sim$ 1 kpc wide strip
("the nuclear strip") running from the south-east to the north-west,
perpendicular to the radio jet, and a narrower component ($\sigma < 100$ km
s$^{-1}$) dominating elsewhere. Centroid velocity maps reveal a rotation
pattern with velocity amplitudes reaching $\sim \pm 350$ km s$^{-1}$ in the
region dominated by the narrow component, while residual blueshifts and
redshifts relative to rotation are observed in the nuclear strip, where we also
observe the highest values of the [N II]/H{\alpha}, [S II]/H{\alpha} and [O
I]/H{\alpha} line ratios, and an increase of the gas temperature ($\sim 18000$
K), velocity dispersion and electron density ($\sim 500$ cm$^{-3}$). We
interpret these residuals and increased line ratios as due to a lateral
expansion of the ambient gas in the nuclear strip due to shocks produced by the
passage of the radio jet. The effect of this expansion in the surrounding
medium is very small, as its estimated kinetic power represents only $2.6 - 3.0
\times 10^{-5}$ of the AGN bolometric luminosity. A possible signature of
inflow is revealed by an increase in the [O I]/H{\alpha} ratio values and
velocity dispersions in the shape of two spiral arms extending to 2.3 kpc
north-east and south-west from the nucleus.
