The First Caltech-Jodrell Bank VLBI Survey
Session 75 -- VLBI Obsesrvations
Display presentation, Friday, January 14, 9:30-6:45, Salons I/II Room (Crystal Gateway)

[75.05] The First Caltech-Jodrell Bank VLBI Survey

W. Xu, A.C.S. Readhead, T.J. Pearson, (Caltech), P.N. Wilkinson, A.G. Polatidis (NRAL, Jodrell Bank, U.K.)

We have completed the first Caltech--Jodrell Bank VLBI survey (CJ1). The CJ1 sample includes all 135 extragalatic sources in the S4 (Pauliny-Toth et al. , 1978, A.J. , 83 , 451) and S5 (K{\"u}hr et al. , 1981, A.J. , 86 , 854) surveys with 0.7 Jy $\le$ $S$(5GHz) $\le$ 1.3 Jy, $\delta$ $\ge$ 35$^\circ$, and $|b|$ $\ge$ 10$^\circ$ which, combined with the Pearson--Readhead sample (1988, Ap.J. , 328 , 114) of 65 sources brighter than 1.3 Jy in the same sky region, provides a complete flux-limited sample of 200 sources. In the past three years we developed and successfully implemented the VLBI-SNAPSHOT'' technique. This new technique has increased the observation efficiency by an order of magnitude. The main objectives of this study are: (1) to classify these objects, based on radio morphologies on all scales and radio spectrum; Such a classification is an essential pre-requisite to understanding the physics and evolution of the radio loud active galaxies; it is also an important observational foundation for testing various Unified Schemes''. (2) to make interesting statistical tests by class, such as cosmological evolution; (3) to reveal the relationships between different classes, if any; and (4) to study the physics of individual objects of interest.

In this paper we will present all the 5 GHz VLBI maps and the morphological classification on both arcsec and milliarcsec scales. On milliarcsec scale the objects are separated into three classes: Compact and Core-Jet, Compact Symmetric Object, and Unclassified , which is a simplified version of the classification scheme of Pearson \& Readhead (1988).