Nuclear radio emission in megaparsec-size radio galaxies

Abstract

We present high resolution radio observations of the nuclear radio emission in a sample of eight radio galaxies having Megaparsec sizes, using the European VLBI network at 18 cm. At a resolution of 25 mas we detect all the giant radio galaxies from our sample. Among them DA 240 and 1331-099 were imaged for an extended period. These observations reveal a twin-jet structure for DA 240 and one-sided core-jet morphology in 1331-099. The implications of our results in the context of the unification of quasars and powerful radio galaxies are discussed. Our results are consistent with the suggestion that powerful radio galaxies are the unbeamed counterparts of quasars.