The Evolution of Galaxy Morphology for Galaxies in the Canada-France Redshift Survey

Abstract

The images of 229 galaxies in the Canada France Redshift Survey have been classified on the DDO system. These observations were combined with previous classifications of galaxies with known redshifts in the Hubble Deep Field. The combined sample provides homogeneous morphological classifications for 425 galaxies of known redshift. The fraction of all galaxies that are of types E + S0 + E/S0 appears to remain approximately constant at ~17% over the redshift range 0.25 < z < 1.2. Over the same range the fraction of irregular (Ir) galaxies increases from ~5% to ~12%. Part of this increase may be due to mild luminosity evolution of Ir galaxies. The frequency of mergers is found to rise by a factor of two or three over the redshift range covered by the present survey.