Page 31 - EngineerIt April 2021

SPACE SCIENCES

Dr Isabella Prandoni of INAF Bologna, Italy added: “Star
formation is usually enshrouded in dust, which obscures our
view when we look with optical telescopes. But radio waves
penetrate the dust, so with LOFAR we obtain a complete
picture of their star formation.” The deep LOFAR images have
led to a new relation between a galaxy’s radio emission and
the rate at which it is forming stars, and a more accurate
measurement of the number of new stars being formed in the
young Universe.
The remarkable dataset has enabled a wide range of
additional scientific studies, ranging from the nature of the
spectacular jets of radio emission produced by massive
black holes, to that arising from collisions of huge clusters of
galaxies. It has also thrown up unexpected results; for example,
by comparing the repeated observations, the researchers
searched for objects that change in radio brightness. This
resulted in the detection of the red dwarf star CR Draconis.
Dr Joe Callingham of Leiden University and ASTRON, noted Prof Oleg Smirnov is on the left of this image, and Dr Cyril Tasse
that “CR Draconis shows bursts of radio emission that strongly is on the right.
resemble those from Jupiter, and may be driven by the
interaction of the star with a previously unknown planet, or capabilities and a treasure trove for future discoveries.”
because the star is rotating extremely quickly.” Looking ahead, Prof. Smirnov concluded, “I’m very
LOFAR does not directly produce maps of the sky; excited to see what we find when we keep applying the same
instead the signals from more than 70,000 antennas must be techniques to MeerKAT, which is an even more sensitive
combined. To produce these deep pictures, more than four telescope, and will show us even more. The depth and breadth
petabytes of raw data - equivalent to about a million DVDs of the window on the Universe that these observations open up
– were taken and processed. “The deep radio images of our is simply unprecedented, so we can expect waves of exciting
Universe are diffusely hidden, deep inside the vast amount of new results going forward.” n
data that LOFAR has observed,” said Dr Tasse, who is currently
based at Paris Observatory, France. “Recent mathematical Video link: https://www.youtube.com/watch?v=nGKEGVBXMxk
advances made it possible to extract these, using large clusters
of computers.” More information about the LOFAR surveys can be found at
“LOFAR is unique in its ability to make high quality images www.lofar-surveys.org.
of the sky at metre wavelengths,” said Prof. Huub Röttgering
of Leiden University, who is leading the overall suite of LOFAR LOFAR is the world’s leading telescope of its type. It is operated
surveys. “These deep field images are a testament to its by ASTRON, the Netherlands Institute for Radio Astronomy,
and coordinated by a partnership of nine European countries:
France, Germany, Ireland, Italy, Latvia, the Netherlands,
Poland, Sweden and the UK. In its ‘high-band’ configuration,
LOFAR observes at frequencies of around 150 MHz – between
the FM and DAB radio bands.
The International LOFAR Telescope is a trans-European
network of radio antennas, with a core located in Exloo in
the Netherlands. LOFAR works by combining the signals
from more than 70,000 individual antenna dipoles, located
in ‘antenna stations’ across the Netherlands and in partner
European countries. The stations are connected by a high-
speed fibre optic network, with powerful computers used
to process the radio signals in order to simulate a trans-
European radio antenna that stretches over 1300 kilometres.
The International LOFAR telescope is unique, given its
sensitivity, wide field-of-view, and image resolution or clarity.
The LOFAR data archive is the largest astronomical data
collection in the world.
LOFAR was designed, built and is presently operated by
ASTRON, the Netherlands Institute for Radio Astronomy.
France, Germany, Ireland, Italy, Latvia, the Netherlands,
Poland, Sweden and the UK are all partner countries in the
Ultra-sensitive radio images reveal thousands of star-forming International LOFAR telescope.
galaxies in early Universe. n

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