September 1, 2004
The European VLBI Network (EVN) is in the process of establishing an e-VLBI array in which the radio telescopes and the EVN correlator at JIVE are connected in real-time, via high-speed national fibre optic networks and the pan-European research network, GEANT. This paper reports on recent test results, including the production of the first real-time e-VLBI astronomical image. In a parallel and related development, the field-of-view of VLBI is also expanding by many orders of magnitude, and the first results of deep, wide-field surveys capable of detecting many sources simultaneously are summarised. The detection of sources as faint as 10 microJy should soon be possible in the era of ``Mk5'' and e-VLBI.
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January 6, 2013
Almost two decades after the establishment of the Joint Institute for VLBI in Europe (JIVE), the European VLBI Network is a thriving scientific infrastructure with a significant user community and a healthy proposal pressure. It offers opportunities to address a breadth of important scientific topics, which feature in national and European astronomy roadmaps. Most of these science themes call for further enhancements of the sensitivity and image quality delivered by VLBI netw...
July 5, 2012
Radio observations using the Very Long Baseline Interferometry (VLBI) technique typically have fields of view of only a few arcseconds, due to the computational problems inherent in imaging larger fields. Furthermore, sensitivity limitations restrict observations to very compact and bright objects, which are few and far between on the sky. Thus, while most branches of observational astronomy can carry out sensitive, wide-field surveys, VLBI observations are limited to targete...
March 6, 2000
In this paper I outline a new strategy for the routine detection and imaging of faint (sub-mJy and microJy) radio sources with VLBI and SVLBI. The strategy relies on a combination of in-beam phase-referencing, wide-field VLBI imaging and simultaneous correlation of multiple field centres. A combination of these techniques, together with the steeply rising radio source counts observed at cm wavelengths, permit routine high resolution observations of radio sources previously co...
January 17, 2003
In this paper, I present the likely technological development of VLBI, and its impact on the astronomical community over the next 1-5 years. VLBI is currently poised to take advantage of the rapid development in commercial off-the-shelf (COTS) PC-based products. The imminent deployment of disk-based recording systems will enable Gbps data rates to be achieved routinely by both cm and mm-VLBI networks. This, together with anticipated improvements in collecting area, receiver s...
May 27, 2002
I review the current status of deep, wide-field VLBI continuum surveys. I also discuss anticipated short and long-term improvements in sensitivity (e.g. the eEVN), and the science these developments will enable.
January 21, 2015
The European VLBI Network is a collaboration of the major radio astronomical institutes in Europe, Asia, South Africa and Puerto Rico. Established four decades ago, since then it has constantly improved its performance in terms made using resolution, data bit-rate and image fidelity with improvements in performance, and the addition of new stations and observing capabilities. The EVN provides open skies access and has over time become a common-user facility. In this contribut...
September 15, 2010
With the exceptional progress e-VLBI has achieved over the last three years, the VLBI of the future has already started. At least for the EVN, it is argued that at some point all VLBI operations should be done in e-VLBI mode. This ambition is based on the scientific case that is described in the EVN2015 science vision. At the same time, it should be taken into account that the long-term future of radio astronomy is connected to the development of the SKA. The consensus in the...
March 25, 2009
Guided by the recently published science case for the future of European VLBI, EVN2015, a roadmap for the future of the EVN is sketched out in this paper. The various desired technical improvements are being discussed with an emphasis on the role of e-VLBI. With this innovation new scientific capabilities are introduced. In this way the EVN is also positioned as an interesting platform for exercising new techniques and operational models, complementary to other SKA pathfinder...
January 5, 2004
Traditionally VLBI observations focus on a small patch of sky and image typically a few 100 mas around a bright source, which is often used to self-calibrate the data. High spectral and time resolution is needed to image a larger area, in principle up to the primary beam of the individual telescopes. The EVN MkIV data processor at JIVE is being upgraded to make such high resolution data its standard product. From the archive of high resolution data it will be possible to imag...
March 27, 2004
A 20-hour VLBI observation with the NRAO VLBA and GBT in the NOAO Bootes field reaches an rms noise of 9 microJy per beam at 1.4 GHz. Three sources were detected at 10-milliarcsecond resolution within the GBT primary beam of FWHM 8.6', including the 20-milliJy calibrator and two sub-milliJy sources. By tapering the visibility data, portions of the VLBA primary beam of FWHM 29' were imaged at poorer sensitivity and resolution to yield five further detections. New developments ...