VLA OBSERVATIONS OF A COMPLETE SAMPLE OF CORE-DOMINATED RADIO-SOURCES

Maps with high dynamic range are presented of a well-defined sample of powerful core-dominated radio sources, all of which have 5-GHz core flux densities >1 Jy. The maps were made at a frequency of 1.64 GHz from combined VLA and B configuration data. A novel technique for producing high dynamic range maps of variable sources from data taken at different epochs is described. It is found that, on average, BL Lac objects are not more core-dominated than the quasars in the sample. This provides no support for the view that BL Lacs are those quasars seen at such small angles to the line of sight that their relativistically beamed core emission swamps that from other components. The results are consistent with most BL Lac objects being the beamed cores of low-luminosity (FRI) radio galaxies