Radio Astronomy in the era of high-speed networks Arpad Szomoru, JIVE STOA/TERENA Workshop, Brussels, April 2 2008, A.
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Radio Astronomy in the era of high-speed networks Arpad Szomoru, JIVE STOA/TERENA Workshop, Brussels, April 2 2008, A. Szomoru, JIVE Outline • Radio Astronomy and VLBI • principles, techniques • e-VLBI and networks • a real-time telescope of intercontinental size • Motivation, results • the transient universe • Reaching beyond current technology • the future of VLBI, SKA pathfinders and the SKA STOA/TERENA Workshop, Brussels, April 2 2008, A. Szomoru, JIVE Radio astronomy • Radio waves with λ of 0.7mm to 90cm • Compared to optical light 400 – 700 nm • Can be detected and amplified with antenna QuickTime™ and a BMP decompressor are needed to see this picture. • radio emission from hot gas between the stars • Super bright emission from vicinity of black holes • Emission from cold neutral gas in galaxies, building material of stars STOA/TERENA Workshop, Brussels, April 2 2008, A. Szomoru, JIVE Radio Astronomy and VLBI • Radio emission from astrophysical sources can be detected against the sky with telescopes larger than a few meters D • Resolution scales with size: • Solution: build larger telescopes! • Only goes so far.... • Or: combine series of telescopes into radiointerferometer • Even longer baselines are needed to see astronomy in motion STOA/TERENA Workshop, Brussels, April 2 2008, A. Szomoru, JIVE STOA/TERENA Workshop, Brussels, April 2 2008, A. Szomoru, JIVE Mass-loss around an old star STOA/TERENA Workshop, Brussels, April 2 2008, A. Szomoru, JIVE Exploding stars in other galaxies Supernova in M81 QuickTime™ and a YUV420 codec decompressor are needed to see this picture. STOA/TERENA Workshop, Brussels, April 2 2008, A. Szomoru, JIVE VLBI digital processing • To reach the faint end of the universe… • Need many big telescopes • And as much frequency space as you can get • i.e. bandwidth! radio sources in the Hubble deep field require several days of integration (Garrett et al., 2000) • Current standard is 1Gb/s • Recording 256 MHz in 2 pols • bits are not sacred, losses tolerable • Recording on parallel hard disks STOA/TERENA Workshop, Brussels, April 2 2008, A. Szomoru, JIVE The next step: e-VLBI • Upgrade EVN to e-EVN • • • • Funding through EXPReS project in 2006 Retrofit correlator to work real-time Help solve last mile problem at telescopes Work closely with NRENs on robust connectivity • And become operational at a competitive sensitivity • Push to 1024 Mb/s limit • Bring in the big telescopes • And the long baselines.. STOA/TERENA Workshop, Brussels, April 2 2008, A. Szomoru, JIVE EXPReS network upgrade STOA/TERENA Workshop, Brussels, April 2 2008, A. Szomoru, JIVE Why e-VLBI is exciting for science • Rapid response for rapid variability • Fast response to requests • Immediate analysis of data, flexible observing • Coordination with current and future observatories • Immediate feedback • Increased robustness • Fewer consumables, logistics • Constantly available VLBI network • Monitoring: for example astrometry • Spacecraft tracking • Growth path for more bandwidth • Increased sensitivity STOA/TERENA Workshop, Brussels, April 2 2008, A. Szomoru, JIVE Radical shortening of timeline Test case: black holes in outburst • Data processing took 1-2 weeks with first images within 48 hours • Publication took less than 2 months STOA/TERENA Workshop, Brussels, April 2 2008, A. Szomoru, JIVE e-VLBI rapid-return science • e-VLBI observation of Supernova SN2007gr • Within weeks of original detection • First EVN Astronomer's Telegram ever... STOA/TERENA Workshop, Brussels, April 2 2008, A. Szomoru, JIVE Data rate improvements STOA/TERENA Workshop, Brussels, April 2 2008, A. Szomoru, JIVE Long-haul connectivity • Important milestone: can be done! • Across cultures and firewalls... • Long round trip time was a real challenge • Cannot be done with TCP/IP • UDP over lightpaths • Several successful demonstrations • Shanghai/Australian stations with European telescopes • Correlation of three Australian antennas at JIVE • Yielding unique astronomy results • limited tests to Chile, Puerto Rico • Future: • Arecibo (on Puerto Rico) being connected by lightpath right now • TIGO (Chile)-Arecibo-Europe test coming up • Hartebeesthoek (S. Africa) still problematic • Most US antennas are not connected! STOA/TERENA Workshop, Brussels, April 2 2008, A. Szomoru, JIVE Roadmap for future radio telescopes Part of Future Infrastructure Roadmap of ESFRI SKA and SKA pathfinders STOA/TERENA Workshop, Brussels, April 2 2008, A. Szomoru, JIVE The future of the e-EVN • Currently the EVN is at the forefront of technological developments • Distributed correlation, use of GRID • Long-haul, high-bandwidth data transport • Use of (dynamic) lightpaths • 4 Gbps systems currently under consideration • (barely) doable using magnetic media • But easily accommodated on 10 Gbps networking architecture • Upgrade of EVN correlator, receiver systems will lead to a massive increase of bandwidth and sensitivity • Will keep EVN competitive and complementary in the era of SKA • Providing global baselines • Located predominantly in Northern hemisphere • Upgrade will lead to ~100 Gbps data streams from telescopes • Maps perfectly onto emerging networking technologies STOA/TERENA Workshop, Brussels, April 2 2008, A. Szomoru, JIVE