We are grateful to the staff of the EVN, NRAO and Hartebeesthoek observatories, and the MPIfR correlator for their support of our project. We thank Joan Wrobel for assistance in preparation and analysis of the global VLBI experiment of 1992 described in the paper, and the referee for a number of very helpful suggestions. ZP and SF acknowledge financial support received from the European Union under contract CHGECT 920011, Netherlands Organization for Scientific Research (NWO) and the Hungarian Space Office, and hospitality of JIVE and NFRA during their fellowship in Dwingeloo. LIG acknowledges partial support from the EU under contract no. CHGECT 920011, the NWO programme on the Early Universe and the hospitality of the FÖMI Satellite Geodetic Observatory, Hungary (supported in part through the contract No. ERBCIPDCT940087 and by the Hungarian Space Office). LIG and RGM acknowledge partial support from the TMR Programme, Research Network Contract ERBFMRXCT 96-0034 "CERES". The National Radio Astronomy Observatory is operated by Associated Universities, Inc. under a Cooperative Agreement with the National Science Foundation. This research has made use of the NASA/IPAC Extragalactic Data Base (NED) which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration.
© European Southern Observatory (ESO) 1999
Online publication: March 10, 1999