Morphologies in Mpc-Size Radio Galaxies

Abstract

The extended radio structures or lobes found in edge-brightened radio galaxies represent interactions with the ambient medium over the source lifetimes. Their study probes the temporal evolution in the radio sources and the properties of the ambient medium encountered at different locations. Previous studies (Leahy & Williams, 1984; Leahy et al., 1989) involved radio galaxies with sizes ~ 400 kpc, and revealed radio morphologies with a variety of off-axis distortions that could be interpreted as due to different ways in which the lobes interact with the galactic halos. Such studies are lacking for radio galaxies having Megaparsec sizes, which extend to distances well beyond the observed galactic halos and are suspected of evolving in a different regime (Baldwin, 1982). Towards learning the evolution of radio galaxies in this size regime, we have carried out a study of a complete sample of Mpc-size radio galaxies; details are presented in Subrahmanyan, Saripalli & Hunstead (to appear in MNRAS, 1996).