VLBI OBSERVATIONS OF A COMPLETE SAMPLE OF RADIO GALAXIES .7. STUDY OFTHE FR-I SOURCES 3C-31, 4C-35.03, AND 3C-264

We present results from global VLBI and VLA observations of three Fana roff-Riley type I radio galaxies, 3C 31, 4C 35.03, and 3C 264, at a fr equency of 5 GHz. In all three cases, we observe asymmetric parsec-sca le structures consisting of a compact core and a single jet pointing i n the direction of the more prominent kiloparsec jet. We interpret suc h alignment as evidence for the relativisitic nature of FR I radio jet s at parsec scales. Comparing the VLBI and VLA images of these sources , we find a progressive deceleration of the plasma flow from parsec to kiloparsec scales. We consider another five FR I radio galaxies studi ed previously by us and find that, in a set of eight FR I objects, the estimated jet bulk velocities and orientation angles with respect to the observer are consistent with the requirements of the unification m odel for low-power radio sources.