Spectroscopic CCD surveys for quasars at large redshift. II - A Pfuei transit survey
A CCD transit survey has been carried out with the 200 in. telescope of a strip of sky 5 arcmin wide and 9 hr long. Direct images and slitless spectra of over 43,000 objects were obtained on two successive nights. An automatic search for emission lines of given minimum equivalent width and signal-to-noise ratio yielded 52 candidate sources. Slit spectra revealed that 24 were emission-line galaxies with z less than 0.4 and eight were quasars with 2 between 1.00 and 2.76. The number of quasars detect agrees with that predicted from luminosity function models for z less than 2.9. The models also indicate that between 30 and 62 quasars with z less than 2.9 should have been found in this survey, but none were detected. This result reconfirms that there is a redshift cutoff near or below redshift three. The apparent conflict of this measurement with the known existence of dozens of quasars with redshifts larger than three is discussed.