CCD surface photometry of radio galaxies - I. FR class I and II sources

Abstract

CCD surface photometry for 47 radio galaxies in the R-band is used to study the differences between Fanaroff and Riley (1974) class I and class II sources. Definitions are developed for classical double, twin jet, and fat double sources. It is shown that classical double sources are generally associated with normal giant elliptical galaxies which are considerably fainter than first-rank galaxies in rich clusters. It is found that twin jet and fat double sources are associated with brighter galaxies. It is suggested that classical doubles (FR class II) do not normally evolve into twin jet (FR class I) sources, because the two types of sources are associated with different galaxies.