$2.6\times10^{-13}$ Pa (the systematic uncertainties dominate over the statistical uncertainties and for this reason we present the internal lobe pressure without errors).

From the surface brightness profile and the measured temperature of the external gas we can find the external pressure at a given radius from the AGN, using the method of @bw93. Fig. \[Pressure\] shows the pressure as a function of radius. We see that the internal pressure is less than the external pressure at radii less than $\sim 80$ arcsec; thus the source should be contracting in its inner regions. Further out, though, the source is overpressured, and the difference is greatest at the far end of the lobes, where $p_{\rm int}/p_{\rm ext} = 2.4$, high enough that the source should be driving a shock into the external medium.

Projection affects both the size of the source (thus affecting the inferred internal pressure from the inverse-Compton measurements) and the environment in which it is embedded, so in general the effect of projection on measurements of internal to external pressure ratio is complicated (e.g. @hw00). In this particular case we expect that the source will be no more than $45^\circ$ from the plane of the sky, since it is 