VLBI in Transition Arpad Szomoru Joint Institute for VLBI in Europe SPIE, Orlando, May 2006, A.
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VLBI in Transition Arpad Szomoru Joint Institute for VLBI in Europe SPIE, Orlando, May 2006, A. Szomoru, JIVE EVN & JIVE • European VLBI Network: collaboration of radio astronomy observatories in Europe, China, South Africa, USA • Central correlator facility in Dwingeloo, the Netherlands: Joint Institute for VLBI in Europe • • • • Operations, user data Network support Visitor facilities Technology development SPIE, Orlando, May 2006, A. Szomoru, JIVE Principle of VLBI SPIE, Orlando, May 2006, A. Szomoru, JIVE SPIE, Orlando, May 2006, A. Szomoru, JIVE Price recording media ($/GB) SPIE, Orlando, May 2006, A. Szomoru, JIVE Data Acquisition • Move from tape to disk recording Disk based recording •Reliability •Cost •Bandwidth •Efficiency • eVLBI: the next step •No consumables •Higher bandwidth •Fast turn-around •ToO support SPIE, Orlando, May 2006, A. Szomoru, JIVE eVLBI using fiber e-VLBI Proof-of-Concept Project • • • • • • • • • • • • • • • • DANTE/GÉANT SURFnet GARR UKERNA PSNC DFN KTHNOC/NORDUnet Manchester University JIVE Westerbork telescope Onsala Space Observatory MRO MPIfR Jodrell Bank TCfA CNR IRA SPIE, Orlando, May 2006, A. Szomoru, JIVE Pan-European Network Dutch NREN Italian NREN UK NREN Polish NREN German NREN Nordic NREN Network application software EVN Correlator Netherlands Sweden Finland Germany UK Poland Italy GÉANT: Access of NRENs to GÉANT NL DE SE CH HU IT FR GR CZ BE AT UK PT 0 GEANT ES SI PL IE HR LU RO EVN telescope LV SPIE, Orlando, May 2006, A. Szomoru, JIVE BG CY LT IL SK EE POC targets: • for the EVN and JIVE • Standards:- Protocols, parameter tuning, procedures at telescope and correlator. • New Capabilities:- Higher data rates, improved reliability, quicker response. • for GÉANT and the NRENs • To see significant network usage with multiple Gbit streams converging on JIVE. • Minimum is three telescopes (not including Westerbork) • Must be seen to enable new science and not just solve an existing data-transport problem • Real-time operation is seen as the ultimate aim, buffered operation accepted as a development stage. SPIE, Orlando, May 2006, A. Szomoru, JIVE SPIE, Orlando, May 2006, A. Szomoru, JIVE SPIE, Orlando, May 2006, A. Szomoru, JIVE Current status: •JIVE: 6 lambdas via Netherlight, each capable of 1 Gbps; 16 * 1 Gbps soon GE lines to •1 Gbps connections to Westerbork, correlator Torun, Onsala, Jodrell Bank, Medicina LX Optics converters •155 Mbps to Arecibo, 128 to Cambridge Cisco ONS 15252 Optical Splitters •Metsahovi being connected at 10 Fibre pair from Correlator Interface Gbps Amsterdam SPIE, Orlando, May 2006, A. Szomoru, JIVE SPIE, Orlando, May 2006, A. Szomoru, JIVE First real-time eVLBI Image, 3 telescope observation of gravitational lens, May 2004 First eVLBI science observation, OH masers around IRC10420, Richards et al, Oct 2004 First broadband eVLBI science, detection of the Hypernova SN2001em, Paragi et al, astro-ph/0505468 SPIE, Orlando, May 2006, A. Szomoru, JIVE Huygens descent tracking • Detection of carrier signal during descent • Salvage of Doppler experiment • Building up experience with spacecraft tracking • Special purpose, extreme narrow band software correlator SPIE, Orlando, May 2006, A. Szomoru, JIVE f 1 2 W I SPIE, Orlando, May 2006, A. Szomoru, JIVE POC results • Demonstration of feasibility • Identification of problems • Has led to closer ties with networking community and generated political interest • Has laid the foundation for the next step forward (EXPReS) SPIE, Orlando, May 2006, A. Szomoru, JIVE The next step… e-VLBI & EXPReS • I3 proposal to the EC (Communication & Network Development Call) • Ranked first out of 43 proposals; nearly fully funded to an amount of 3.9 MEuro. EXPReS = EXpress Production Real-time e-VLBI Service SPIE, Orlando, May 2006, A. Szomoru, JIVE EXPReS aims • Upgrade EVN to e-EVN • 16 station real-time array • Help solve last mile problem • Including connections on a global scale • Software in field and correlator to become real real-time • Investigate/apply lambda switching • And look beyond 1 Gb/s • More capacity on digital sampling, more bandwidth • As being implemented for eMERLIN in UK • Hardware (PC-based) and protocols for transport • Correlator with more capacity: distributed correlation SPIE, Orlando, May 2006, A. Szomoru, JIVE Expanding the e-VLBI Network SPIE, Orlando, May 2006, A. Szomoru, JIVE Field of View limitation VLBI FoV x 100 • Limited by tint • Time smearing • Shorter integrations • Enable wide field surveys • Study μJy sources • Discriminate AGNs • But, enormous increase of output data volume.. 6 arcmin [FWHP] Effelsberg beam SPIE, Orlando, May 2006, A. Szomoru, JIVE PCInt, high speed read-out • VLBI field of view limited by correlator output rate • New hardware enabling high speed parallel read-out of correlator boards to dedicated cluster • Achieved 1/16s sampling • At 24 MB/s data output • Users seem to be ready for 800 GB data-sets… SPIE, Orlando, May 2006, A. Szomoru, JIVE Archive • All output data on line • Several TB, dominated by few projects • Public one year after last epoch • Together with calibration info • All meta-data, schedules etc. • Quality control plots • Will need strategy to deal with data increase SPIE, Orlando, May 2006, A. Szomoru, JIVE Advanced Long Baseline User Software • RadioNet project JBO, MPIfR, ASTRON • Addresses calibration issues for radio-interferometry, in particular VLBI • Ionosphere, troposphere • Improved data product with Tsys and PC • Data distribution selection tools • Parallelization for large data sets • eMERLIN, EVN and WSRT will produce user data sets of up to 1TB • Focus on high-level parallelization • Wide band and wide field imaging SPIE, Orlando, May 2006, A. Szomoru, JIVE Conclusions • eVLBI is changing the nature of VLBI • Fast response, ToO capability • better quality control, rapid data delivery • New science, higher bandwidths • Large fields of view • Allows one to study μJy sources • Or many masers over a large star formation region • Data archive will contain millions of weak sources • Introduction of new algorithms • Improved calibration • Methods to deal with vast data sets SPIE, Orlando, May 2006, A. Szomoru, JIVE