Calibration of the magnetic field strengths in classical double radio lobes

We propose to observe with XMM a small number of classical double radio sourceswhich, when combined with our (and archival) existing data, will comprise acomplete sample of these targets at z > 1. We wish to make the firstmeasurements of the magnetic field strengths of the synchrotronemitting plasmalobes of a complete sample in order to establish the dependence of magneticfield strength on the underlying jet power. If such a link could be established,it would be an important clue as to whether jets are magnetically launched fromthe vicinity of their black holes or whether the magnetic fields in the lobesthey feed are merely selffields. truncated!, Please see actual data for full text [truncated!, Please see actual data for full text]