European VLBI Network
|Location(s)||Various sites across Europe and the rest of the world|
|Wavelength||18cm, 6cm, 3.6cm, 1.3cm and 0.7cm|
|Angular resolution||5, 1.5, 1, 0.3 or 0.15 milliarcseconds (depending on observing frequency)|
The European VLBI Network (EVN) was formed in 1980 by a consortium of five of the major radio astronomy institutes in Europe (the European Consortium for VLBI). Since 1980, the EVN and the Consortium has grown to include 9 institutes with 12 radio telescopes in 8 western European countries as well as associated institutes with telescopes in Italy, Poland, Russia, Ukraine, China and South Africa. Proposals for additional telescope in Spain are under consideration, and furthermore, the EVN can be linked to the 7-element Jodrell Bank MERLIN interferometer in the UK and to the US Very Long Baseline Array (VLBA) to create a "global network". In 1993 the Joint Institute for VLBI in Europe (JIVE) was created, with the Netherlands Foundation for Research in Astronomy (Dwingeloo) acting as the host institute. It will provide both scientific user support and a correlator facility. Very Long Baseline Interferometry (VLBI) achieves ultra-high angular resolution and is a multi-disciplinary technique e.g. imaging of extragalactic radio sources, geodesy and astrometry.
The EVN network consists of 21 telescopes:
Additionally the EVN often links with the UK-based 7-element Jodrell Bank MERLIN interferometer. It can also be connected to the US Very Long Baseline Array (VLBA), achieving a global VLBI, obtaining sub-milliarcsecond resolution at frequencies higher than 5 GHz.
Since 2004, the EVN has started to be linked together using international fibre optic networks, through a technique known as e-VLBI. The EXPReS project was designed to connect telescopes at Gigabit per second links via their National Research Networks and the Pan-European research network GÉANT2, and make the first astronomical experiments using this new technique. This allows researchers to take advantage of the e-EVN's Targets of Opportunity for conducting follow-on observations of transient events such as X-ray binary flares, supernova explosions and gamma-ray bursts.
EXPReS's objectives are to connect up to 16 of the world's most sensitive radio telescopes on six continents to the central data processor of the European VLBI Network at the Joint Institute for VLBI in Europe (JIVE). Specific activities involve securing "last-mile connections" and upgrading existing connections to the telescopes, updating the correlator to process up to 16 data streams at 1 Gbit/s each in real time and research possibilities for distributed computing to replace the centralized data processor.