Evolution of Galactic Disks in Clusters and the Field at 0.1 < [ITAL]z[/ITAL] < 0.6 in the CNOC Survey

Two-dimensional surface photometry is presented for a sample of 351 late-typegalaxies with $0.12 < z < 0.65$. These objects are drawn from the CanadianNetwork for Observational Cosmology (CNOC) cluster survey and are eitherspectroscopically confirmed members of clusters at $z=0.23$ (64 galaxies),$0.43$ (45), and $0.55$ (36) or field galaxies with similar redshifts. Galaxiesin the rich cluster Abell 2256 at $z=0.06$ were also analyzed with the samemethods to provide a local reference point. 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 $\Delta \mu_{0}(B) =(-0.58\pm 0.12,-1.22\pm 0.17,-0.97\pm 0.2$)mag, respectively, relative to the Freeman (1970) constant surface-brightnessrelation; whereas disks in cluster galaxies at $z=0.06$ are consistent withthat relation. Field galaxies show a progressive disk-brightening with redshiftthat is consistent with that seen in the cluster population. Taken togetherwith similar measurements of early-type galaxies (Schade et al. 1996a), theseresults suggest that the evolution of the field and cluster galaxy populationsare similar, although we emphasize that our sample of cluster galaxies isdominated by objects at large distances (up to 3 Mpc) from the dense clustercore, so that the implications of these findings with respect to theButcher-Oemler effect and the morphology-density relation will not be clearuntil an analysis of galaxy properties as a function of cluster-centricdistance is completed.