EVOLUTION OF GALACTIC DISKS IN CLUSTERS AND THE FIELD AT 0.1-LESS-THAN-Z-LESS-THAN-0.6 IN THE CNOC SURVEY

Two-dimensional surface photometry is presented for a sample of 351 la te-type galaxies with 0.12 < z < 0.65. These objects are drawn from th e Canadian Network for Observational Cosmology (CNOC) cluster survey a nd are either spectroscopically confirmed members of clusters at z = 0 .23 (64 galaxies), 0.43 (45), and 0.55 (36) or field galaxies with sim ilar redshifts. Galaxies in the rich cluster Abell 2256 at z = 0.06 we re also analyzed with the same methods to provide a local reference po int. At redshifts of (0.23, 0.43, 0.55) the disk surface brightness in cluster late-type galaxies is higher in the B band by Delta mu(0) (B) = (-0.58 +/- 0.12, -1.22 +/- 0.17, -0.97 +/- 0.2) mag, respectively, relative to the Freeman (1970) constant surface brightness relation; w hereas disks in cluster galaxies at z = 0.06 are consistent with that relation. Field galaxies show a progressive disk brightening with reds hift that is consistent with that seen in the cluster population. Take n together with similar measurements of early-type galaxies, these res ults suggest that the evolution of the field and cluster galaxy popula tions are similar, although we emphasize that our sample of cluster ga laxies is dominated by objects at large distances (up to 3 Mpc) from t he dense cluster core, so that the implications of these findings with respect to the Butcher-Oemler effect and the morphology-density relat ion will not be clear until an analysis of galaxy properties as a func tion of clustercentric distance is completed.