The Impact of Global High-Speed Networks on Radio Astronomy

Abstract

The advent of worldwide high-speed optical networks has drastically changed the operational model of VLBI (Very Long Baseline Interferometry). This document describes these changes through a time line of an e-VLBI observation at the EVN-correlator from an operational point of view. All the tools that are needed to setup and run a successful e-VLBI session are discussed in chronological order. Tools developed especially for e-VLBI by the EXPReS project group will be mentioned and suggestions on possible improvements are given where appropriate. Because the incoming data from the telescopes are being processed at the correlator in real time, problems with the correlator system can cause total data loss from all the participating telescopes. It is therefore important to realize that the job of the correlator operator is directly related to the success of the e-VLBI observation, with respect to the monitoring of the data quality and error checking. New tools that will help the operator detect and solve problems in the data or with the network need to be developed. Our experiences from working with this online scientific instrument can be beneficial to other users or developers of online and distributed Grid based systems.