Quasar candidates from grens plates

Positions and magnitudes are given for 439 quasar candidates discovered on CFHT blue grens plates, as well as for some white dwarfs and intergalactic H II regions. Spectroscopic observations with the MMT indicate that 70 percent of the candidates are quasars, and most of the remaining objects are white dwarfs or hot subluminous stars. The MMT observations also reveal that about 68 percent of the quasars have redshifts less than z = 1.7, in marked contrast to the results of other slitless spectra type surveys. Most of the approximately 33 candidates found on each plate are located in the central 0.5 sq deg. The corresponding surface densities of objects which are probably quasars are higher than the estimates of Veron and Veron (1982) and Woltjer and Setti (1982) for magnitudes brighter than m = 19. The redshifts of quasars estimated from their grens spectra peak sharply at z = 2.2. Several pairs suggestive of membership in superclusters are present, including a pair of quasars at z = 3.3.