Canada-France Redshift Survey .11. Morphology of high-redshift field galaxies from high-resolution ground-based imaging

The 143 galaxies with secure redshifts (z(median) = 0.62) from the 1415+52 field of the Canada-France Redshift Survey have been imaged with median seeing of 0''.67 (FWHM). Structural parameters have been derived by fitting multicomponent models and the results confirm two phenomena seen in a smaller sample of galaxies imaged with the Hubble Space Telescope. First, 11 +/- 3% of the galaxies lie off the normal locus of color versus bulge fraction B/T. This class of objects (''blue nucleated galaxies,'' or BNGs) was identified using HST observations (Schade et al. 1995, hereafter CFRS IX), and it was shown that they are associated with peculiar/asymmetric structure and merger/interactions. The observed frequency of BNGs in this sample is 14 +/- 4% 0.5 < z < 1.2 and 6(-3)(+6)% at 0.2 < z < 0.5, but the true frequency is likely to be a factor similar to 2 higher after corrections are made for the effect of asymmetric/peculiar structures. Galaxy disks at 0.5 < z < 1.1 are found to have a mean rest-frame, inclination-corrected central surface brightness of mu(AB)(B) = 19.8 +/- 0.1 mag arcsec(-2), similar to 1.6 mag brighter than the Freeman (1970) value. At low redshift (0.2 < z < 0.5) the mean surface brightness [U-AB(B) = 21.3 +/- 0.25] is consistent with the Freeman value. These results are consistent with the HST observations. With larger numbers of galaxies and therefore more statistical weight they demonstrate the capabilities, and limits, of ground-based work in the study of galaxy morphology at high redshift.