1Shanghai Observatory, Chinese Academy of Sciences, Shanghai 200030, China
2Purple Mountain Observatory, Chinese Academy of Sciences, China
Abstract:
OQ208 is used ore and more frequently as a VLBI calibrator of flux density. A VLBI image of OQ208 at 5 GHz is firstly provided in this paper. Its structure consists of a compact core and a component. The angular distance between the core and the component is about 7 milli-arcsecond; the position angle is ?125 degrees. In principle, OQ208 is not an ideal VLBI calibrator of flux density. This paper provides the structural information for correcting the structure effect when OQ208 is to be used as a calibrator.