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50 years of VLBI!!

Submitter: Ilse van Bemmel
Description: This month the astronomy community is commemorating the 50th anniversary of the first successful VLBI (Very Long Baseline Interferometry) experiment. This was conducted in Canada on 17th April 1967, following many attempts in both Canada and the US, and theoretical proof of concept by Soviet Union authors. The successful experiment aimed to coordinate independent radio telescopes located 3074 kilometres apart, to focus on a single bright but compact radio source at exactly the same time. The Canadian team was headed up by Norman W. Broten and Alan Yen. Their detection of quasars on such a long baseline confirmed the compact nature of these radio sources, which were already at the time suspected to be associated with black holes. It took until 1995, and the combination of VLBI with optical spectroscopy to solidly confirm the presence of a supermassive black hole in the centre of galaxy NGC 4258.

Use of VLBI has increased the understanding of many astrophysical phenomena. It is also an essential tool for geodesy studies. This is only achieved because of the continued growth of VLBI technology, which has led to improved sensitivity and ever increasing quality (and quantity) of data collected during VLBI experiments.

Over the last decades, the Joint Institute for VLBI ERIC (JIVE) has played a key role in fostering this growth, through its dedicated support of the European VLBI Network (EVN), one of the leading global VLBI networks. JIVE and EVN are dedicated to the continued development of new technology to support the global astronomy community. In recognition of the hard work from all VLBI pioneers 50 years ago, we pay homage to the Canadian team and many others who opened up the VLBI door.

The image shows the 26-m telescope located at Dominion Radio Astrophysical Observatory, one of the original telescopes used in the first VLBI experiment. The second telescope, at Algonquin Radio Observatory, is currently operated by a company called Thoth Technology http://thothx.com/space-tracking-communications/.
Copyright: JIVE; the image is licensed by Darren Kirby, under CC. by-SA 2.0.
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