A team of astronomers and engineers at ASTRON, the Netherlands Institute for Radio Astronomy, has successfully detected correlated interferometric radio signals, so-called "fringes", from the sky with the first three, recently completed, full-scale LOFAR stations.

Published by the editorial team, 20 July 2009

The Low Band Antenna (LBA) stations were pointed at Cygnus A, a very powerful radio galaxy associated with an ultra massive black hole. The signals from this galaxy travelled for 600 million years to get here - once the signals were received at the LOFAR stations, they started a new and much shorter journey via the fiber network that is connected to the IBM Blue-Gene supercomputer in Groningen. From there, the correlated data were sent to Dwingeloo for final processing.


The first complete LOFAR station, located near Exloo, Drenthe. This station was one of several that performed the first astronomical observations. The photo shows the different LOFAR Low-band and High-band antennas.

Copyright: ASTRON



The team observed the entire frequency band from 30 to 78 MHz at a spectral resolution of 763 Hz. A day later, the experiment was successfully repeated using the High Band Antennas (HBAs) between 120 and 168 MHz. The stations that were used were between 5 and 20 km apart. Once completed, LOFAR will consist of more than 50 stations distributed across Europe with baselines ranging from 30 m up to 1500 km.

Dr. Michiel Brentjens, one of the astronomers at ASTRON: "This may seem quite straightforward, but many things had to go right to get these results. If one element in the chain does not work, you do not get the right data on your screen." According to Brentjens the data quality is superb, much better than expected at this early stage in the telescopes commissioning phase. Prof. Michael Garrett, general director of ASTRON, praised the efforts of his staff, and the contribution of other national and international partners: "This is a major step forward for the LOFAR project. The first results give us a taste of what will follow; we are truly opening up a new window on the early Universe."


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On June 13-17, the LOFAR Family Meeting took place in Cologne. After two years LOFAR researchers could finally meet in person again. The meeting brings together LOFAR users and researchers to share new scientific results.

Our renewed ‘Melkwegpad’ (Milky Way Path) is finished! The new signs have texts in Dutch on the one side and in English on the other side. The signs concerning planets have a small, 3D printed model of that planet in their centre.
#Melkwegpad @RTVDrenthe

Daily image of the week

The background drawing shows how the subband correlator calculates the array correlation matrix. In the upper left the 4 UniBoard2s we used. The two ACM plots in the picture show that the phase differences of the visibilities vary from 0 to 360 degrees.

Daily image of the week: Testing with the Dwingeloo Test Station (DTS)
One of the key specifications of LOFAR2.0 is measuring using the low- and the highband antenna at the same time. For this measurement we used 9 lowband antenna and 3 HBA tiles.