National Institute of Information and Communications Technology (NICT) has developed a new VLBI sampler unit named K5/VSSP32 dedicated to e-VLBI which is a successor to the K5/VSSP. The maximum sampling frequency per channel of the K5/VSSP32 is 64 MHz, which is four times as fast as that of K5/VSSP. In addition to the maximum sampling frequency, there is a difference in the interface to a host ...

We present results from global VLBI, VLBA,MERLIN and VLA observations of the quasar 3C395 at 5.0 GHz, global VLBI and VLBA observations at 8.4 GHz, and VLBI test observations at 22.2 GHz. These combinations allow us to obtain radio images with resolutions ranging from 0.2 to 200 milliarcseconds, which show the continuity of the radio structure of 3C395 from parsec to kiloparsec scales. On parse...

We present 5 GHz space-VLBI observations of the quasar pair B 1342+662 / B 1342+663 that demonstrate the feasibility of phase-reference techniques using an antenna in space. The space-based data were taken by the satellite HALCA, of the space-VLBI mission VSOP. From residual (referenced) phases we derive an upper bound of 10 meters to the uncertainty of the spacecraft orbit reconstruction. An a...

The OH main line masers in circumstellar shells were observed with astrometric VLBI in order to accurately determine the position of the star, as well as its motion, including the parallax. Results are presented on 4 Mira stars monitored for 2-8 years with the VLBA. The data show that in some stars the VLBI detection is dominated by blue-shifted emission that is associated with the stellar imag...

Phase-referencing allows phase calibration of VLBI data. Using regular observations of a nearby calibrator source, delay, delay-rate, and phase corrections can be derived and their eeects removed from the target source visibility data. This technique allows imaging much weaker objects than is possible via fringe-tting methods. We examine the main types of phase error in VLBI observations (geome...

Millimeter wave very long baseline interferometry (mm-VLBI) provides access to the emission region surrounding Sagittarius A* (Sgr A*), the supermassive black hole at the center of the Milky Way, on sub-horizon scales. Recently, a closure phase of 0◦ ± 40◦ was reported on a triangle of Earth-sized baselines (SMT–CARMA–JCMT) representing a new constraint upon the structure and orientation of the...

We apply an efficient selection method to identify potential weak Very Long Baseline Interferometry (VLBI) target quasars simply using optical (SDSS) and low-resolution radio (FIRST) catalogue data. Our search is restricted to within 12 from known compact radio sources that are detectable as phase-reference calibrators for ASTRO-G at 8.4 GHz frequency. These calibrators have estimated correlate...