The X-ray nuclei of FRII radio galaxies: unification and accretion modes

We have recently shown that a population of powerful radio galaxies, thelowexcitation FRII radio galaxies, appears to have no accretionrelated nuclearXray emission, despite having highluminosity radio jets: plausibly theseobjects are accreting via a different, radiatively inefficient accretion modecompared to the better understood narrowline radio galaxies and quasars. Thispicture is consistent with other information from the optical and infraredbands, but the crucial Xray constraints come from a small and inhomogenoussample. We propose observations of a sample of lowexcitation and narrowlineradio galaxies which will greatly increase our sample size and allow us to makedefinitive statements about the nature of the accretion mode in these objects. truncated!, Please see actual data for full text [truncated!, Please see actual data for full text]