GÉANT2 network helps create real-time virtual telescope 11,000 km in diameter

23 May 2008

Telescopes from around the world were today successfully connected in real-time, enabling astronomers from the EXPReS project to simultaneously observe active galaxies in the distant universe. GÉANT2, the high bandwidth, pan-European research network managed by research networking organisation DANTE, was at the heart of this collaboration, working with other research data networks across the globe, under the coordination of the Joint Institute for VLBI in Europe (JIVE).

Telescopes in Chile, Germany, Italy, the Netherlands, Puerto Rico, South Africa and Sweden were linked to simulate a telescope almost 11,000 kilometres in diameter. The telescopes simultaneously observed quasar 3C454.3, a bright fringe-finder source, and other targets, and streamed the data in real-time to JIVE at an aggregated rate of 1.44 Gbps. There, the data was correlated in real-time, and results were transmitted to Bruges, Belgium, as part of a live demonstration at the TERENA Networking Conference 2008.

Through a technique called Very Long Baseline Interferometry (VLBI), astronomers use multiple radio telescopes to simultaneously observe the same region of sky. The data collected by each telescope is sampled, synchronised and correlated for every possible telescope combination. This technique can generate images of cosmic radio sources with up to a hundred times better resolution than images from the best optical telescopes. EXPReS, a three-year project funded by the European Commission, is networking the telescopes to send the data electronically and correlate it in real-time. Called e-VLBI, this process eliminates the shipping of disks and provides astronomers with correlated data in a timely fashion, allowing them to exploit short-lived astronomical events such as supernovae and gamma ray bursts.

"The scale and power of the EXPReS project revolutionises how astronomers can view the universe by enabling them to collaborate across the globe," commented Dai Davies, general manager, DANTE. "Working with JIVE and our networking colleagues to create this demonstration shows the potential that high speed networking provides to the research community, across the globe."

Data from TIGO (Transportable Integrated Geodetic Observatory) in Chile was sent via the REUNA and RedCLARA networks in South America to GÉANT2, the pan-European GÉANT2 network operated by EXPReS project member DANTE, and then via Netherlight, which is operated by EXPReS member SURFnet, for final transmission to Bruges, via JIVE. Data from the Arecibo telescope in Puerto Rico was routed via the Centennial, AMPATH, AtlanticWave, NGIX, Internet2 and StarLight networks to GÉANT2 and Netherlight. Data from South Africa used the Ubuntunet link to GÉANT2.

"By linking telescopes across the globe to create an internationally distributed electronic Very Long Baseline Interferometer (e-VLBI) we will be able to chart evidence of previously unseen astronomical events," commented Dr Huib Jan van Langevelde, coordinator for the EXPReS project and director of JIVE. "Scalable, high speed networks are central to our mission and working with partners such as DANTE enables us to push back the frontiers of astronomy."

Participation in the EXPReS project demonstration is part of GÉANT2's strong presence at the TERENA Networking Conference (TNC). Held in Bruges, Belgium between 19-22 May 2008, the event, brought together research networking professionals from around the world, and saw 17 sessions given on the GÉANT2 network.

- Source: DANTE