Searches for high redshift radio galaxies

We have started a search for High Redshift Radio Galaxies (HzRGs) in an area covering 7 sr by selecting a sample of Ultra Steep Spectrum (USS) sources with a low flux density cut-off S{sub 1400} > 10 mJy and a steep spectral index {alpha} < -1 3 (S {alpha} {nu}{sup {alpha}}) using the WENSS, NVSS and TEXAS radio suveys. Preliminary results for 25 sources shows that we are almost twice as effective in finding HzRGs than previous searches using brighter radio sources and less steep radio spectra ({alpha} < -1 0) The redshift distribution is consistent with an extension of the z - {alpha} relation to {alpha} < -1 3, but a large fraction of our sample (40%) consists of objects which are too faint to observe with 3-4m class telescopes The first results from our Keck K- band imaging and spectroscopy program indicate that these faint objects are our best candidates to detect HzRGs at z > 3 5 Our search is aired at significantly increasing the number of very high redshift radio galaxies for further detailed studies of the formation and evolution of massive galaxies and their environmen