EVNJIVE+EVN (European VLBI Network)


Francisco Colomer
Oude Hoogeveensedijk 4, 7991 PD Dwingeloo
+31 (0) 521-596512
ASTRON and international partners

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 at centimetre wavelengths 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 facilitating effective inter-operation among European radio astronomy institutes. Five telescopes larger than 60-m diameter 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 routinely in conjunction with the UK e-MERLIN array that introduce baselines as short as 20 km, as well as with telescopes in the US and/or Australia to provide significantly more baselines in the range of 6000-11000 km and to boost resolution further.
1 If. 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 open skies policies and observations can be proposed by users from all over the world, with data products and support provided by JIVE, which became a European Research Infrastructure Consortium (ERIC) in 2015.
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 phasecentre 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 1-2Gbps 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.

EVN members are encouraged to keep their facilities upgraded since this is a requirement for the network to remain state-of-the-art, including in particular upgrades in antenna performance, receivers, backends,connectivity, etc. 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 VLBI networks, the EVN is the most 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 and evolution. 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 (ertrc.strw.leidenuniv.nl).

There is demonstrated potential for the EVN to make more impact in the areas of geodetic VLBI, satellitetracking applications, and in planetary science as well. In particular JIVE staff is involved in high precision determination of state vectors of planetary missions.

Aansluiting bij strategische ontwikkelingen
Not applicable
Oorsprong van het leven- op aarde en in het heelal
Bouwstenen van materie en fundamenten van ruimte en tijd
Waardecreatie door verantwoorde toegang tot en gebruik van big data