Abstract of the proposal for the experiment EC063B


Radio galaxies have been discovered for more than 6 decades, but the dynamic properties and evolution of the extragalactic sources are still not well known. The knowledge of the low-radio-power galaxies is even poor. Recently a population of compact, low-power sources were founded, which are named as FR 0, compared to the higher populations of FR I/IIs. We argue that the small size of sources place them in zone of Medium-sized Symmetric Objects (MSOs) in the Power-Size diagram. What is the nature of FR 0s - are they the lowest-power of evolved FR I/II radio galaxies, frustrated MSOs, or a mixture of frustrated MSOs and still-growing FR I ? The proper motions of the jet or separation speed of the hotspots offer critical information to distinguish between two interpretations. VLBI is the only tool to image the sources at pc scale. Here we select a sample of 8 FR 0s with jet/hotspot features and with only one-epoch VLBI data. The new 8.4 GHz VLBI data would enable the proper motion determination over a time span of ~20 years. We also request 5 GHz observation to identify the flat-spectrum core.