
At least half the radio galaxies at z>1 in the 7C Redshift Survey have extremely red colours (R-K>5), consistent with stellar populations which formed at high redshift (z>5). We discuss the implications of this for the evolution of massive galaxies in general and for the fraction of near-IR-selected EROs which host AGN, a result which is now being tested by deep, hard X-ray surveys. The conclusion is that many massive galaxies undergo at least two active phases: one at z~5 when the black hole and stellar bulge formed and another at z~1-2 when activity is triggered by an event such as an interaction or merger.
6 pages, 2 figures, to appear in the proceedings of the workshop on "QSO hosts and their environments", IAA, Granada, 10-12 Jan 2001, Ed. I. Marquez
Astrophysics (astro-ph), FOS: Physical sciences, Astrophysics
Astrophysics (astro-ph), FOS: Physical sciences, Astrophysics
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