Optical integral field spectroscopy of the extended line emission around six radio-loud quasars

We present integral field spectroscopy of a small sample of radio-loud quas ars at intermediate redshift (0.26 < z < 0.60), most of which are associate d with large radio sources. All have oxygen line emission extended over ten s of kpc, and these nebulae display a diverse range in both morphology and kinematic behaviour. Two quasars show 'plumes' of extended line emission, t wo show a clumpy structure and a further one shows a smooth distribution. T here is no clear pattern with regard to the distribution of the ionized gas in relation to the radio source axis; the extended emission-line regions a re found both parallel and perpendicular - and also totally unrelated to - the radio axis. The velocity structure of the ionized gas ranges from essen tially static to apparent smooth rotation, and in two cases shows a clear a ssociation with the radio source. Given the disparity in properties, the ne bulae all show a surprisingly similar ionization state, as measured by the extended lines of [O II] lambda 3727 and [O III] lambda 5007. Assuming the gas is ionized by at least the nearby quasar nucleus, we use the emission l ine ratios to infer a pressure in the ionized gas; in all cases we find it to be at high pressure, suggesting confinement by an external (probably int racluster) medium.