Space-VLBI phase-reference mapping and astrometry

¹ Departamento de Astronomía, Universitat de València, 46100 Burjassot, Valencia, Spain
² Observatorio Astronómico, Universitat de València, 46100 Burjassot, Valencia, Spain
³ Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, 53121 Bonn, Germany
⁴ Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California 91109, USA
⁵ Observatoire de Paris-Meudon-CNRS, 92195 Meudon Principal Cedex, France
⁶ Istituto di Radioastronomia, CNR, Via P. Gobetti, 101, 40129 Bologna, Italy

Corresponding author: J. C. Guirado, jcg@vlbi.daa.uv.es

Received: 17 January 2001
Accepted: 9 March 2001

Abstract

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 analysis of the phase-reference maps of the sources additionally suggests that the above mentioned uncertainty is likely not larger than 3 meters. With errors of this magnitude, HALCA is a useful tool for astrometric studies of close pairs of radio sources.