The Radio Galaxy K-z Relation to z~ 4.5

Using a new radio sample, 6C* designed to find radio galaxies at z > 4 along with the complete 3CRR and 6CE sample we extend the radio galaxy K — z relation to z ~ 4.5. The 6C* K — z data significantly improve delineation of the K — z relation for radio galaxies at high redshift (z > 2). Accounting for non-stellar contamination, and for correlations between radio luminosity and estimates of stellar mass, we find little support for previous claims that the underlying scatter in the stellar luminosity of radio galaxies increases significantly at z > 2. This indicates that we are not probing into the formation epoch until at least z ≳ 3