PINPOINTING THE CENTER OF ACTIVITY IN COMPACT SYMMETRICAL OBJECTS .1.SOURCES FROM THE PEARSON-READHEAD SURVEY

We use multifrequency, multiepoch VLBA observations to pinpoint the ce nter of activity (or ''core'') in five compact symmetric objects (CSOs ) and one candidate CSO from the Pearson-Readhead sample. We provide a first identification of the core component in two sources, and we hav e discovered that the cores of the objects 0108 + 388 and 2352 + 495 w ere previously misidentified. The precise location of the central engi ne in CSOs is crucially important for understanding their interaction with the surrounding environment and their evolution. All six objects studied here are found to display considerable asymmetry in their jets , especially near the core. The likely cause of this asymmetry is diff erences in density of the surrounding medium.