We review some aspects of radio continuum polarimetric imaging of high redshift radio galaxies .
The correlation between extreme values of Faraday rotation observed toward radio emitting structures in nearby radio galaxies , and X-ray emitting cluster atmospheres , is presented as a method for targeting objects at high redshift for deep X-ray searches .
We present an X-ray detection of the extreme rotation measure radio galaxy PKS 1138 - 262 at z = 2.156 , and we argue that the X-ray emission is from a cluster atmosphere with a luminosity of 1.7 \pm 0.3 \times 10 ^ { 44 } h ^ { -2 } ergs sec ^ { -1 } .
We also present results on the correlation between size and redshift for a sample of ultra-luminous radio galaxies between 0 < z < 4.3 .
Source sizes decrease systematically with redshift , suggesting either denser environments , or younger sources , at high redshift .
An alternative explanation is significant inverse Compton losses off the microwave background at high redshift .