| Description |
We propose Herschel observations of the virtually complete sample of 3CR radio-galaxies and quasars in the redshift range 1 < z < 2.5, and a representative additional set of 4C objects extending to redshift z = 3, in order to quantify the orientation-dependence of AGN radiation (AGN unification), to investigate the interplay between accretion onto the central black-hole and star-formation in the hosts, to understand the evolution of the black-hole/stellar-bulge relation, and to make the first accurate assay of the energetics of AGN at the epoch of their peak activity, the quasar era. The low-frequency radio-selection provides us with very powerful and massive active galaxies free from any orientation/obscuration bias, a requirement for testing AGN unification. The properties of particularly the high-z 3CR sources are well known throughout the electromagnetic spectrum, except in the rest-frame mid- and far-IR, where they were hitherto outside the reach of space missions. We propose PACS/SPIRE 70-500 micron photometry of 71 3CR+4C sources in 5 bands, in order to measure their detailed spectral energy distributions between available Spitzer and SCUBA/MAMBO data. The rest-frame FIR emission serves as an isotropic calorimeter and the MIR/FIR luminosity ratio is determined by the relative strength of the AGN and star-forming contributions combined with dust obscuration. These observations will return crucial new information on the energy processes in powerful AGN and their hosts at the cosmic heyday, providing an essential anchor for studies of galaxy and AGN evolution. |
