Ultra–Steep Spectrum Radio Galaxies at Hy Redshifts

Radio sources have traditionally provided convenient beacons for probing the early Universe. Hy Spinrad was among the first of the tenacious breed of observers who would attempt to obtain optical identifications and spectra of the faintest possible ‘radio galaxies’ to investigate the formation and evolution of galaxies at hy redshift. Modern telescopes and instruments have made these tasks much simpler, although not easy, and here we summarize the current status of our hunts for hy redshift radio galaxies (HyZRGs) using radio spectral and near–IR selection. 1. Hy Z Radio Galaxies: Why? The first optical identifications of (bright) radio sources with (faint) galaxies were made when Hy Spinrad was still a teenager (Windhorst 1999; these proceedings). After that it was soon realized that the ‘invisible’ universe of radio sources provided convenient beacons to locate very distant galaxies and thus might be used to study their formation and evolution. As so eloquently described by Presently at: Leiden Observatory, Leiden, The Netherlands University of California at Davis, CA 95616 Presently at: JPL, 4800 Oak Grove Drive, Pasadena, CA 91109