XMM-Newton observations of three high-redshift radio galaxies

We present the results of XMM-Newton observations of three powerful high-redshift radio galaxies 3C184, 3C292 and 3C322. Although none of the sources lies in as rich an X-ray-emitting environment as is seen for some powerful radio galaxies at low redshift, the environments provide sufficient pressure to confine the radio lobes. The weak gas emission is particularly interesting for 3C184, where a gravitational arc is seen, suggesting the presence of a massive cluster. Here, Chandra data complement the XMM-Newton measurements by spatially separating X-rays from the extended atmosphere, the nucleus and the small-scale radio source. For 3C292, the X-ray-emitting gas has a temperature of ~2 keV and a luminosity of 6.5 × 10⁴³ erg s^-1, characteristic of a poor cluster. In all three cases, structures where the magnetic-field strength can be estimated through combining measurements of radio synchrotron and inverse-Compton X-ray emission are consistent with being in a state of minimum total energy. 3C184 and 3C292 (and possibly 3C322) have a heavily absorbed component of nuclear emission of N_H~few times 10²³ cm^-2.