The formation of stars in the universe
Philip Best, a professor of extragalactic astrophysics at the University of Edinburgh who led the in-depth investigation, explained: “When we observe the sky with radio telescopes, the brightest celestial bodies we see are produced by the huge black hole in the center of the galaxy. However, Our images are so deep that most of the celestial bodies are galaxies like our own Milky Way, which emit weak radio waves to track their ongoing star formation.”
“The combination of the high sensitivity of LOFAR and the vast sky covered by our survey–about 300 times the full moon–allows us to detect tens of thousands of galaxies like the Milky Way, far away in the distant universe. The light from these galaxies has traveled billions of years to reach Earth; this means that we are seeing galaxies billions of years ago when they were forming most of the stars.”
Isabella Prandoni of INAF Bologna (Italy) added: “The formation of stars is usually shrouded in dust. When we observe with optical telescopes, it obscures our vision. But radio waves can penetrate dust, so with LOFAR, we can Obtain a complete image of its star formation. The in-depth LOFAR image enables a new relationship between the radio emission of a galaxy and the speed at which it forms stars, and a more accurate measurement of the number of new stars forming in the young universe .”
This outstanding data set has led to a series of additional scientific studies, from the properties of the spectacular radio jets produced by massive black holes to the radio jets produced by the collision of huge clusters of galaxies. It also brought unexpected results. For example, by comparing repeated observations, the researchers searched for celestial bodies with varying radio brightness. This led to the detection of the red dwarf CR Draconis. Joe Callingham of Leiden University and ASTRON (Netherlands) pointed out: “CR Draconis showed a burst very similar to the radio emission from Jupiter, possibly driven by the interaction of the star with a previously unknown planet, or because of the star. It is spinning very fast.”
Huge computing challenge
LOFAR does not directly generate a map of the sky; instead, signals from more than 70,000 antennas must be combined. To make these deep pictures, more than 4PB of raw data–equivalent to approximately one million DVDs–was shot and processed. “Cyril Tasse from the Paris Observatory and PSL University (France) said: “The deep radio images of our universe are scattered and hidden, hidden in the large amount of data observed by LOFAR. Recent advances in mathematics have made it possible for us to use large computer clusters to extract these data. “
Multi-wavelength data
In extracting scientific knowledge, it is also important to compare these radio images with data obtained at other wavelengths. Philip Best explained: “The part of the sky we chose is the best studied in the northern sky. This allows the research team to collect optical, near-infrared, far-infrared, and sub-millimeter data for the galaxies detected by LOFAR, which is useful for explaining LOFAR. The results are crucial.”
PROMISES
LOFAR is the leading telescope of its kind in the world. It is operated by ASTRON, the Netherlands Institute of Radio Astronomy, and coordinated by nine European countries. France, Germany, Ireland, Italy, Latvia, the Netherlands, Poland, Sweden and the United Kingdom. In its “high-band” configuration, LOFAR observes at a frequency of approximately 150MHz-between the FM and DAB radio bands. Huub Röttgering of Leiden University said: “LOFAR is unique in that it can produce high-quality images in a one-meter-long sky,” he is leading the overall investigation of LOFAR. “These deep-field images are proof of its capabilities and a treasure trove of future discoveries.”
These published papers can be found in “Astronomy and Astrophysics”websiteFound on.