A. G. Polatidis — Page 3

arXiv1999

The Youngest Lobe-Dominated Radio Sources

We present an analysis of multi-epoch global VLBI observations of the Compact Symmetric Objects: 2352+495 and 0710+439 at 5 GHz. Analysis of data spread over almost two decades shows strong evidence for an increase in separation of the outer components of both sources at a rate of ~0.2 h^{-1} c (for q_{0}=0.5 and H_{0}=100 h kms^{-1} Mpc^{-1}). Dividing the overall sizes of the sources by their separation rates implies that these Compact Symmetric Objects have a kinematic age < 10^{4} years. These results (and those for other CSOs) strongly argue that CSOs are indeed very young sources and that they are probably evolve into the much larger classical doubles.

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arXiv1997

The Caltech-Jodrell Bank VLBI Surveys

The Caltech-Jodrell Bank VLBI surveys of bright extragalactic radio sources north of declination 35 deg were carried out between 1990 and 1995 using the Mark-II system, achieving images with a resolution of about 1 mas at 5 GHz. The CJ1 survey (together with the older `PR' survey) includes 200 objects with 5 GHz flux density greater than 0.7 Jy; the CJ2 survey includes 193 flat-spectrum sources with 5 GHz flux density greater than 0.35 Jy; and we have defined a complete flux-density limited sample, CJF, of 293 flat-spectrum sources stronger than 0.35 Jy. We summarize the definition of the samples and the VLBI, VLA, MERLIN, and optical observations, and present some highlights of the astrophysical results. These include: (1) superluminal motion and cosmology; (2) morphology and evolution of the `compact symmetric objects' (CSOs); (3) two-sided motion in some CSOs; (4) the angular-size - redshift diagram; (5) misalignment of parsec-scale and kiloparsec-scale jets.

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