  Sub-arcsecond imaging of the X-ray emission in the type 2 AGN Mrk 78 with
Chandra shows complex structure with spectral variations on scales from
$\sim$200 pc to $\sim$ 2 kpc. Overall the X-ray emission is aligned E-W with
the radio (3.6 cm) and narrow emission line region as mapped in [OIII], with a
marked E-W asymmetry. The Eastern X-ray emission is mostly in a compact knot
coincident with the location where the radio source is deflected, while the
Western X-ray emission forms a loop or shell $\sim$2 kpc from the nucleus with
radius $\sim$0.7 kpc. There is suggestive evidence of shocks in both the
Eastern knot and the Western arc. Both these positions coincide with large
changes in the velocities of the [OIII] outflow. We discuss possible reasons
why the X-ray shocks on the Western side occur $\sim1$ kpc farther out than on
the Eastern side. We estimate that the thermal energy injected by the shocks
into the interstellar medium corresponds to $0.05-0.6$% of the AGN bolometric
luminosity.
