Launching LOFAR
The fifth German LOFAR station DE605 has just been opened in the grounds of the Forschungszentrum Jülich, one of the biggest research centers in Europe. The new station is an integral part of the world’s largest digital radio telescope LOFAR – short for Low Frequency Array – and will contribute to measuring long-wave radio signals from dawn of the universe. LOFAR station DE605 has been built in cooperation with the Ruhr-Universität Bochum, Jacobs University and the Forschungszentrum Jülich with funds provided by the Federal Ministry for Research and Education (BMBF).
October 5, 2011The station, one of 44 spread out over the whole of Europe, measures the size of a soccer field and consists of two main areas: a field of antennas to measure high frequencies (between 110 and 240 megahertz) with 96 receivers and 16 antennas, and a field to measure low frequencies (between 10 and 80 megahertz) with 96 dipole antennas.
“An even ground and the availability of fast network connections are necessities for building such a station. Conditions at Jülich have been ideal in both areas,” says Prof. Dr. Marcus Brüggen, Professor of Astrophysics and head of the LOFAR project at Jacobs University.
The Jülich-based facility is the last in a series of five similar LOFAR stations set up in Germany. The Forschungszentrum Jülich provides the network capacity for all five stations as well as computers to analyze data. At Jülich data will be collected and sent to the central LOFAR supercomputer at the University of Groningen where incoming data from the five antenna locations is correlated.
Telescope networks such as LOFAR have number of distinct advantages: They can monitor different directions at the same time thereby covering the whole sky and don’t need to be adjusted continuously as is the case giant single dishes. Prof. Dr. Sebastian M. Schmidt, member of the board at the Forschungszentrum Jülich says: “LOFAR is the first virtual telescope. For a while its realization proved to be difficult due to technical problems mainly with data processing.”
LOFAR is the first of a new generation of radio telescopes, which consist of a number of spread-out antenna fields. With 36 stations in the Netherlands, five stations in Germany and three other European stations. LOFAR is the biggest digital radio telescope network in the world working mostly in the as-yet-unexplored frequency range between 10 and 240 megahertz.
“LOFAR has opened a new window for radio astronomers,” explains Prof. Dr. Ralf-Jürgen Dettmar from the Faculty of Physics and Astronomy at the Ruhr-Universität Bochum. “We can now trace hydrogen clouds that were formed shortly after the Big Bang, but LOFAR will also lead to new findings when researching active galaxies and quasars or detecting magnetic fields in the universe.”
In future, an even bigger radio telescope named “Square Kilometer Array” (SKA) will be developed in a world-wide cooperation project scheduled to be finished in 2022. While LOFAR covers an area of half a square kilometer, SKA will be twice as big covering a total area of one square kilometer. SKA will further enable astronomers to understand the so-called “Dark Ages” - 300,000 years after the Big Bang, when the first young galaxies started to form.
About LOFAR (www.lofar.org)
LOFAR explores the sky in a largely uncharted, very low radio frequency range and is expected to make ground-breaking new discoveries. While classical radio telescopes collect cosmic radiation with motor-operated dish-like antennas, which scan different areas of space with computer-controlled movements, LOFAR does not require any moving parts. It consists of a set of simple, small radio antennas that are spread all over Europe. The incoming data from the different antenna locations are correlated by one of the world’s fastest supercomputers located in Groningen (The Netherlands). This way, the array of antennas acts like a giant radio-telescope with an equivalent dish-size of more than 1,000 kilometers in diameter, which not only provides the telescope with a so far unparalleled sensitivity, but also enables astronomers to scan space in several directions at the same time. Thus the giant telescope allows scientists to study how distant galaxies take shape, to find out when the early universe was first lit up, to probe the properties of energetic cosmic particles, to map magnetized structures all across the sky, and to monitor the sun’s activity as well as a wide range of variable and explosive celestial objects.
