X-ray emission in powerful radio galaxies and quasars

ROSAT is the first mission to have detected X‐ray emission in radio galaxies which are both powerful (l_(178 MHz)>10^(27) W Hz^(−1) sr^(−1)) and distant (z>0.4), enabling test of ''unified schemes'' through a comparison of the X‐ray and radio properties of powerful quasars and radio galaxies. These radio galaxies are faint in X‐rays, but, nevertheless, ROSAT is capable of resolving any associated X‐ray‐emitting gas of cluster dimension. We present ROSAT PSPC observations of two such radio galaxies and suggest that there is a component of unresolved X‐ray emission in powerful, high‐redshift radio galaxies which may be related to the radio core; this will be tested by ROSAT observations of other powerful radio galaxies.