The optical properties of low luminosity radio galaxies with radio jets

Abstract

Broad-band CCD images of 24 low luminosity radio galaxies containing radio jets have been obtained to study their optical properties. Surface photometry of the galaxies was performed by fitting ellipses to the light distribution in order to obtain the surface brightness profile and the geometrical parameters of the galaxies. The optical morphology, the photometric parameters, and the local environment of the galaxies are discussed and compared with the results for other galaxy samples. The galaxies in this work have absolute magnitudes similar to bright cluster galaxies, and they are more luminous than powerful radio sources. They inhabit regions of higher galaxy density than powerful radio galaxies and radio-quiet ellipticals. A fraction as large as 75% ofthe galaxies show morphological peculiarities in the optical, indicating gravitational interaction with nearby companions and/or recent merging. We argue that low luminosity radio galaxies could be the precursors of cD galaxies in clusters or groups of galaxies, on the basis oftheir optical luminosity, the local environment, presence of extended envelopes, indications ofmerging processes, x-ray emission, and presence of dumbbell systems and multiple nuclei.