EVNJIVE+EVN (European VLBI Network)

Contact details:

Prof. dr. H.J. van Langevelde
Oude Hoogeveensedijk 4, 7991 PD, Dwingeloo
Arecibo Observatory, Arecibo, Puerto Rico; Institute of Applied Astronomy, St. Petersburg, Russia;Max-Planck Institut für Radioastronomie, Bonn, Germany; Hartebeesthoek Radio Astronomy Observatory, Krugersdorp, South Africa; Observatorio Astronómico Nacional,Alcála de Henares, Spain; Jodrell Bank Observatory, Macclesfield, UK; Jodrell Bank Observatory, Macclesfield, UK; Istituto di Radioastronomia, Bologna, Italy;Aalto University Metsähovi Radio Observatory, Espoo, Finland; Onsala Space Observatory, Gothenburg, Sweden; Shanghai Astronomical Observatory, Shanghai, China; Institute of Applied Astronomy, St. Petersburg, Russia; Korea Astronomy and Space Science Institute (KASI), Daejeon, Korea; Torun Centre for Astronomy, Torun, Poland; Xinjiang Astronomical Observatory, Urumqi, China; ASTRON, Dwingeloo, Netherlands; Bundesamt für Kartographie und Geodäsie (BKG)/ Forschungseinrichtung Satellitengeodäsie (FESG), Bad Kötzting, Germany;

Very Long Baseline Interferometry (VLBI) is a technique that combines data from radio telescopes distributed on a global scale to act as a single, powerful instrument. The European VLBI Network (EVN) consists of radio telescopes in Europe, Asia and South Africa. The central data processor and archive of the EVN is located at JIVE in Dwingeloo, the Netherlands. JIVE provides support for observations and data analysis, and it runs various innovation programmes to advance the VLBI technique and to develop new data processing methods. JIVE is therefore the central hub for very high angular resolution radio astronomy in Europe

JIVE is the central user facility of the EVN, which is a consortium of institutes in nine European
countries, plus Russia, China, South Korea, South Africa, and Puerto Rico. From its formation in
1980 the EVN has led the way in bringing about effective inter-operation among European radio
astronomy institutes. Five telescopes larger than 60m provide unmatched sensitivity to the array.
The telescopes in Asia and Africa create baselines longer than 8000 km, providing milli-arcsecond
(mas) resolution at cm wavelengths. The EVN also observes in conjunction with telescopes in the US
and/or Australia to provide significantly more baselines in the range of 6000-11000 km and to boost
sensitivity further, and is working towards being able to include the individual telescopes of the UK
e-MERLIN array to introduce baselines as short as 20 km.
JIVE provides the central correlation facility for the EVN and it is also the legal entity that engages
with EC programmes. The EVN has a long tradition of being an open collaboration and continues to
expand by adding new telescopes. The EVN has adopted an open skies policies and observations can
be proposed by users from all over the world, with data products and support provided by JIVE.
The current EVN software correlator has been developed in-house, providing features that were not
previously available, such as pulsar binning/gating (including coherent de-dispersion), multiple
phase-centre output, near-field correlation for solar-system targets, use of space antennas, and a
phased-up mode for pulsar timing. Connectivity upgrades at most telescopes have led to routine
1Gbps data rates in real-time e-EVN. These rates enable higher sensitivity in projects studying
transient sources, which benefit from this more dynamically responsive mode of operation. The e-
EVN has been designated a pathfinder for the ESFRI-listed radio astronomy facility SKA.
Research with the EVN covers a broad range of topics from Galactic to extragalactic astronomy and
astrophysics. The VLBI technique provides the highest angular resolution imaging in astronomy, and
among all the operational VLBI networks, the EVN is the most the sensitive. This unique
infrastructure is expected to make important contributions for example in the following research
areas: strong field tests of gravity, growth of the first generation supermassive black holes,
detection of dark matter mini-halos at cosmological distances, supernovas hidden in starburst
galaxies, ultra-precise astrometry of pulsars to aid the detection of the gravitational-wave
background, kinematics and magnetic fields in star formation. The European Radio Telescope Review
Committee (ERTRC) initiated by the ASTRONET board has concluded that the EVN delivers a wide
range of excellent science and will remain the premier VLBI instrument during the SKA1 era
There is demonstrated potential in geodetic VLBI, satellite-tracking applications, and in planetary
science as well. In particular JIVE staff is involved in high precision determination of state vectors of
planetary missions.

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