Research Networks and Astronomy Richard Schilizzi Joint Institute for VLBI in Europe

Three types of use Transport of raw data from telescope(s) to data processing facility or database distribution of data from processing facility or database to users “mining’’ of databases

Transport of raw data Required capacity is driven by radio telescope arrays national scalee-MERLIN LOFAR European scaleeEVN global scaleSKA

Hubble Deep Field 2500 galaxies in a small area of sky radio source in the centre of the galaxy deep in the heart of the galaxy (zoom factor=1000) black hole?

Data mining in astronomy Current Future ASTROVIRTEL Astrophysical Virtual Observatory dataset sizes 100’s gigabytes to 100’s terabytes at multiple sites database access needs several gigabit/sec pan-European connectivity distributed computing via the Grid e.g. astrometric satellite GAIA

eEVN: a real-time connected radio telescope as large as Europe plans to use the “Grid infrastructure” for - transporting raw data-streams from the telescopes to the central data processor at JIVE (via GÉANT) - real-time control of the distributed observing process - distributing processed data to scientists - data mining of archives to provide –new astronomical capabilities –operational reliability and flexibility

Science impact wide bandwidth that is always available major increase in sensitivity for sources at the edge of the universe wide bandwidth very high quality imaging flexible, dynamic scheduling essential for making movies of variable sources like exploding stars

supernova in M81in 1993 (Bietenholz et al)

Operational impact improved reliability easier data logistics flexible scheduling lower operating costs more effective network monitoring

eEVN pilot project: 2001 to 2004 link 4 of the 14 EVN telescopes (and possibly 1 US telescope) to JIVE using as much off-the-shelf technology as possible - bit rates up to 1 Gbps with latency < 1 second - network monitoring and astronomical end-to-end testing for several periods of weeks at a time

Technology challenges networking at multiple gigabit/sec via concatenated national, regional and pan-European research networks including Géant++. Quality of Service. last mile connections to remote telescope sites will Grid architectures and middleware be adequate for the expected data traffic and distributed computing? networking at terabit/sec rates on the longer term

Summary radio astronomy interferometry is a novel application of Grid capabilities for sustained data transfer at high bit rates from the telescopes to the central data processor VLBI network characteristics: heterogeneous, multipoint to point, asymmetric Challenges to be met: - international connectivity at 1 Gbps - latency - cost (including last mile connections)

Radio telescope arrays networks of radio telescopes spread over 100’s to 1000’s of km provide zoom lenses for astronomers and gives them the most detailed pictures of distant stars and galaxies available to mankind technique is called Interferometry

e-MERLIN Dedicated optical fibres to connect telescopes to Jodrell Bank Observatory near Manchester Sustained data rates of 30 Gbps/telescope to new data processor

LOFAR Configuration Log-spiral distribution, 300 km total data rate to centre ~ 20 terabit/sec

eEVN: European VLBI Network 1-8 Gbps Data processing centre Gbps China USA Network characteristics multi-point to point asymmetric heterogeneous South Africa

 telescopes in different countries  data recorded on “standard” tape at 1 Gbps and transported to a central location (300 tera-bytes/day)  data processor multiplies and adds at a rate of ops/sec how do we currently do this? VLBI configuration Recorder + atomic clock Recorder + atomic clock cross multiplication = signal detection astronom- ical data at < 128 MB/s Difference in time of arrival

SKA Square Kilometer Array global collaboration technical concepts under evaluation operational in 2015 data rates up to terabit/sec

ESO Very Large Telescope 4 x 8-m optical telescopes on Paranal in Chile adaptive optics IR spatial interferometry all four elements in operation HQ in Germany

GAIA Satellite and System a high precision census of more than a billion stars in our Galaxy Launch date: 2010 Data rate: 1 Mbs -1 sustained 3 Mbs -1 downlink (1 ground station) Design lifetime: 5 years ESA only mission

GAIA Data Analysis: Concept and Requirements Capacity: ~ Terabytes (20 TB of raw data) Overall system: centralised global iterative reduction approach Accessibility: quasi-random, in both temporal and object domains Processing requirements: entire task is ~10 19 flop Data base structure: e.g. Objectivity (cf. Sloan, CERN, etc) Time critical: some results available in minutes (near-Earth asteroids, supernovae etc) Challenge: complexity of algorithms; inter-dependence of data; volume of data on-line