High angular resolution images of extragalactic radio sources are being made with the Highly Advanced Laboratory for Communications and Astronomy (HALCA) satellite and ground-based radio telescopes as part of the Very Long Baseline Interferometry (VLBI) Space Observatory Programme (VSOP). VSOP observations at 1.6 and 5 gigahertz of the milli–arc-second–scale structure of radio quasars enable the quasar core size and the corresponding brightness temperature to be determined, and they enable the motions of jet components that are close to the core to be studied. Here, VSOP images of the gamma-ray source 1156+295, the quasar 1548+056, the ultraluminous quasar 0014+813, and the superluminal quasar 0212+735 are presented and discussed.

No abstract

No abstract

The radio astronomy satellite HALCA was launched by the Institute of Space and Astronautical Science in 1997 February to participate in Very Long Baseline Interferometry (VLBI) observations with arrays of ground radio telescopes. HALCA is the main element of the VLBI Space Observatory Programme (VSOP), a complex international endeavor involving over 25 ground radio telescopes, five tracking stations and three correlators. Simultaneous observations with HALCA's 8 meter diameter radio telescope and ground radio telescopes synthesize a radio telescope over twice the size of the Earth, enabling the highest resolution 1.6 GHz and 5 GHz images to be made.

No abstract