Two-sided ejection in powerful radio sources: The compact symmetric objects
We present very long base interferometry (VLBI) images of the compact high-luminosity radio galaxy 2352+495 that show symmetric structure on either side of a prominent central core. This contrasts strongly with the asymmetric nuclear structure exhibited by the great majority of powerful extragalactic sources. The outer structure of 2352+495 takes the form of two 'mini-lobes' containing hot spots; in this respect this compact radio galaxy resembles extended radio galaxies, but its overall size, ~150 pc, is ~1000 times smaller. A reanalysis of existing data on the radio galaxy 0710+439 shows similar compact structure, and together these VLBI images confirm the existence of a class of two-sided compact symmetric objects (CSOs). We show that, in contrast to nuclear radio sources in other powerful objects, the observed structure of CSOs is not dominated by relativistic beaming effects. It is likely that many objects previously classified as 'compact doubles' will prove to be CSOs when mapped with VLBI with high dynamic range.
© 1994 The American Astronomical Society. Received 1994 May 3; accepted 1994 June 28. We are grateful to the staff at the many observatories who contributed to the success of the first Caltech-Jodrell Bank VLBI survey. This work was supported in part by grants from the National Science Foundation (AST 88-14554 and AST 91-17100).
Published - 1994ApJ___432L__87W.pdf