Absorption Systems in the Spectra of 66 z > 4 Quasars

We present high signal-to-noise, 5 A resolution (FWHM) spectra of 66 z \ga 4 bright quasars obtained with the 4 m Cerro Tololo Inter-American Observatory and 4.2 m William Hershel telescopes. The primary goal of these observations was to undertake a new survey for intervening absorption systems detected in the spectra of background quasars. We look for both Lyman-limit systems (column densities N(HI) > 1.6 * 10^{17} atoms cm-2) and damped Ly-alpha systems (column densities N(HI) > 2 * 10^{20} atoms cm-2). This work resulted in the discovery of 49 Lyman-limit systems, 15 of which are within 3000 km s-1 of the quasar emission and thus might be associated with the quasar itself, 26 new damped Ly-alpha absorption candidates, 15 of which have z>3.5 and numerous metal absorption systems. In addition ten of the quasars presented here exhibit intrinsic broad absorption lines.