EXPReS: Real-time e-VLBI Service for Large-Scale Astronomical Instrumentation

1. What is EXPReS? • EXPReS = Express Production Real-time e-VLBI Service • Three year project (March 2006-2009) funded by the European Commission (DG-INFSO), Sixth Framework Programme, Contract #026642 EXPReS • Funded at 3.9 million EUR • International collaboration: 19 radioastronomy institutes and research and education networks (NRENs) representing 14 countries on 6 continents • Objective: to create a distributed, large-scale astronomical instrument of continental and inter-continental dimensions • Means: high-speed communication networks operating in real-time and connecting some of the largest and most sensitive radio telescopes on the planet to the central correlator in the Netherlands EXPReS- TITLE OF YOUR PRESENTATION

2. EXPReS Partners 14 Countries, 6 Continents Radio Astronomy Institutes • Joint Institute for VLBI in Europe (Coordinator), The Netherlands • Arecibo Observatory, National Astronomy and Ionosphere Center, Cornell University, USA • Australia Telescope National Facility, a Division of CSIRO, Australia • Institute of Radioastronomy, National Institute for Astrophysics (INAF), Italy • Jodrell Bank Observatory, University of Manchester, United Kingdom • Max Planck Institute for Radio Astronomy (MPIfR), Germany • Metsähovi Radio Observatory, Helsinki University of Technology (TKK), Finland • National Center of Geographical Information, National Geographic Institute (CNIG-IGN), Spain • Hartebeesthoek Radio Astronomy Observatory, National Research Foundation, South Africa • Netherlands Foundation for Research in Astronomy (ASTRON), NWO, The Netherlands • Onsala Space Observatory, Chalmers University of Technology, Sweden • Shanghai Astronomical Observatory, Chinese Academy of Sciences, China • Torun Centre for Astronomy, Nicolaus Copernicus University, Poland • Transportable Integrated Geodetic Observatory (TIGO), University of Concepción, Chile • Ventspils International Radio Astronomy Center, Ventspils University College, Latvia National Research and Education Networks (NRENs) • AARNet, Australia • DANTE, United Kingdom • Poznan Supercomputing and Networking Center, Poland • SURFnet, The Netherlands EXPReS- TITLE OF YOUR PRESENTATION

3. Participating Telescopes and Network Paths* Image created by Paul Boven, JIVE. Satellite image: Blue Marble Next Generation courtesy of NASA Visible Earth (visibleearth.nasa.gov). *Logical network paths. EXPReS- TITLE OF YOUR PRESENTATION

4. EXPReS Network Diagram EXPReS- TITLE OF YOUR PRESENTATION

5. Activities # Description Leader PC Project Coordinator Huib Jan van Langevelde, JIVE NA1 Management of I3 T. Charles Yun, JIVE NA2 EVN-NREN Forum John Chevers, DANTE NA3 eVLBI Science Forum John Conway, Chalmers NA4 Public Outreach Kristine Yun, JIVE SA1 Production Services Arpad Szomoru, JIVE SA2 Network Provisioning Francisco Colomer, CNIG-IGN JRA1 FABRIC Huib Jan van Langevelde, JIVE EXPReS- TITLE OF YOUR PRESENTATION

6. What is VLBI? • Astronomy technique: Very Long Baseline Interferometry • A radio telescope looks at an object in the sky and collects data to create an “image” of the source. • Multiple telescopes can view the same object simultaneously. The distance between the telescopes is the baseline. The baseline can be compared to building a single telescope with the diameter of this distance (sort of). • The resolution increases with additional telescopes and longer baselines. • The sensitivity of the image increases with the data collection rate at the telescope. • A central processor decodes, aligns and correlates the data for every possible telescope combination. • Result: images of cosmic radio sources with up to a hundred times better resolution than images from the best optical telescopes EXPReS- TITLE OF YOUR PRESENTATION

7. Image Credits: Avruch and Pogrebenko The science of e-VLBI Aperture Synthesis Imaging • A technique that uses a number of telescopes to simulate a much larger one. A larger dish, real or simulated, improves image clarity and brightness. This requires coordination between the telescopes and a supercomputer. Consider the examples displaying aperture size, aperture distribution and image quality. EXPReS- TITLE OF YOUR PRESENTATION

8. Interferometry Makes a Virtual Telescope EXPReS- TITLE OF YOUR PRESENTATION

9. What is the correlator? • Dedicated, purpose-designed and purpose-built hardware • Synthesis imaging simulates a very large telescope by measuring Fourier components of sky brightness on each baseline pair • Decodes, aligns and correlates the data for every possible telescope combination • EVN MkIV data processor at JIVE • custom silicon, 1024 chips • Input data is 1 Gb/s max • Around 100 T-operations/sec EXPReS- TITLE OF YOUR PRESENTATION

10. Interferometry EXPReS- TITLE OF YOUR PRESENTATION

11. What is e-VLBI? • Electronic VLBI • Instead of recording data and shipping disks to the central processor, immediately transport data over networks and correlate it in real-time. • Benefits: • eliminate weeks from the observation & correlation schedule • monitor problems in data collection • detect transient events and schedule near-immediate follow-on observations • automate observation EXPReS- TITLE OF YOUR PRESENTATION

12. Traditional VLBI vs. e-VLBI EXPReS- TITLE OF YOUR PRESENTATION