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 141 5+52 field of the Canada-France Redshift Survey have been imaged with median seeing of 0''.67 (FWHM). Structural parameters have been derive d by fitting multicomponent models and the results confirm two phenome na seen in a smaller sample of galaxies imaged with the Hubble Space T elescope. First, 11 +/- 3% of the galaxies lie off the normal locus of color versus bulge fraction B/T. This class of objects (''blue nuclea ted galaxies,'' or BNGs) was identified using HST observations (Schade et al. 1995, hereafter CFRS IX), and it was shown that they are assoc iated with peculiar/asymmetric structure and merger/interactions. The observed frequency of BNGs in this sample is 14 +/- 4% 0.5 < z < 1.2 a nd 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 effec t of asymmetric/peculiar structures. Galaxy disks at 0.5 < z < 1.1 are found to have a mean rest-frame, inclination-corrected central surfac e 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 consi stent with the Freeman value. These results are consistent with the HS T observations. With larger numbers of galaxies and therefore more sta tistical weight they demonstrate the capabilities, and limits, of grou nd-based work in the study of galaxy morphology at high redshift.