Digital Agenda: EU funded research helps astronomers see the bigger picture

Met dank overgenomen van , gepubliceerd op dinsdag 23 augustus 2011.

Radio astronomers observe celestial objects to understand how galaxies evolve and interact with each other. Traditional Very Long Baseline Interferometry (VLBI) observations are performed by telescopes distributed across several countries that simultaneously point at the same source. The greater the distance between telescopes, the better they can distinguish the small details of the source. Each station traditionally recorded data on hard disks that were shipped to a central supercomputer where the data was analysed. The new e-VLBI technique allows telescopes to connect directly to the central supercomputer via optical fibres, avoiding the costs of managing storage media and bringing much faster results. The data is then processed in real-time, providing astronomers with scientific results in a matter of hours rather than weeks. Previously limited to Europe, the e-VLBI technique is now being used on a global scale.

The e-VLBI technique was recently used to observe a "Seyfert galaxy" revealing the emission of powerful gamma rays thought only to originate from the most powerful type of black holes. No other galaxy of this kind had ever been detected at such high energy, and it could be the first member of a new class of cosmic objects. These e-VLBI observations have been made possible through the use of a global, real-time network of the largest and most sensitive radio telescopes in Europe, East Asia and Australia as far apart as 12,458 km, connected through high-speed optical networks.

Background

e-VLBI observation is testing new frontiers, since it allows real-time monitoring and the possibility to deliver immediate results, which is essential for coordination with other observatories at other wavelengths. More radio telescopes are expected to become connected through real-time high-speed networks, and the NEXPReS project is advancing technology to remove the distinction between traditional VLBI and e-VLBI techniques.

e-VLBI has also has other uses: it can be used 'in reverse' to measure the motion of the Earth's tectonic plates and help to predict earthquakes; it can observe variations in the Earth's orientation and length of day, which can in turn be used in climate change research, and to measure the speed of gravitational waves in fundamental physics research. To do so, a global network of antennas measures time differences from distant sources (such as pulsars) over a period of time.

Through the EXPReS project, which ran from 2006 to 2009, the supercomputer at the Joint Institute for VLBI in Europe (JIVE) in The Netherlands has been upgraded for e-VLBI operations. It can receive data from up to 16 telescopes at a time at 1 Gb/s from each telescope. The supercomputer now offers regularly scheduled e-VLBI sessions, as well as opportunities for observations of transient cosmological objects, such as exploding stars, possibly connected to the formation of black holes.

More on EXPReS project - http://www.expres-eu.org/

NEXPReS (Novel Explorations Pushing Robust e-VLBI Services) is a three-year project running from 2010 until 2013 with the goal of implementing real-time, e-VLBI into all observations conducted by the European VLBI Network, a collaboration of the major radio astronomical institutes in Europe, Asia and South Africa. This will enable better data quality and deeper images of the galaxy that can be offered to a larger number of astronomers. NEXPReS is carried out by 15 research institutes, National Research and Education Network (NREN) providers and advanced computing facilities in Australia, Denmark, Finland, Germany, Italy, Latvia, The Netherlands, Poland, Spain, Sweden, and the United Kingdom.

More on NEXPReS project - http://www.nexpres.eu/

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N. (Neelie) Kroes