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The most detailed radio images of galaxies outside the Milky Way were picked up by a network of 70,000 radio antennas in nine European countries.
The images reveal one side of the universe invisible to optical telescopes and provide insight into some of the most mysterious cosmic phenomena, such as the activity of supermassives black holes in the galactic centers.
A team of astronomers behind the Low Frequency Array (LOFAR), a radio telescope network managed by the Dutch Institute for Radio Astronomy (Astron), worked for 10 years to produce the images.
Leah Morabito, assistant professor of physics at Durham University in England, has led efforts to improve the standard resolution of LOFAR images. By including more antennas and using supercomputers, they improved the resolution by a factor of 20.
Related: The Very Large Array: 40 years of revolutionary radio astronomy
Morabito told Space.com in an email that the images offer the highest resolution ever recorded in the FM radio frequency band, a band between 88 and 108 megahertz that is used for radio broadcasting on Earth. The biggest achievement, however, has been being able to combine that high resolution with a wide field of view, she added.
“It’s totally unique,” Morabito said. “This will allow us to study the entire northern sky in just a few years. Telescopes with comparable resolution have a field of view almost 20 times smaller, and therefore a survey of the entire sky is not logistically possible. . No other current or planned radio telescope will have this combination of field of view and resolution. “
Celestial objects, including stars, some planets, and black holes emit radio waves, which are not visible to optical telescopes. Unlike visible light, these radio waves penetrate through clouds of dust and gas, revealing an image of the universe that would otherwise be hidden.
Supermassive black holes are among the most powerful sources of radio waves in the universe. The LOFAR imaging campaign therefore focused on them, in search of jets material ejected from these black holes, which cannot be detected in the optical spectrum.
“These high-resolution images allow us to zoom in to see what actually happens when supermassive black holes launch radio jets, which was not previously possible at frequencies near the FM radio band,” Neal Jackson of the University of Manchester in England, which cooperated on the project, said in a report issued by Astron.
LOFAR generally only uses antennas in the Netherlands. But that limits the diameter of the virtual telescope’s lens to just 120 kilometers. The diameter of the telescope, in turn, limits its resolution.
Astronomers, however, found a way to integrate antennas in nine European countries, which allowed them to increase the diameter to 1,200 miles (2,000 km) and achieve 20 times better resolution.
Observations made by the individual antennas were digitized and combined into the final high resolution images. But it was no small feat. Scientists had to process 1.6 terabytes of data per second, the equivalent of over 300 DVDs.
“To process such huge volumes of data, we have to use supercomputers,” Frits Sweijen of Leiden University in the Netherlands said in the statement. “These allow us to turn terabytes of information from these antennas into gigabytes of science-ready data, in just days.”
Morabito added that it would take 3,000 observations to image the entire northern sky. The images and the scientific papers they spawned were published in a special edition of the journal Astronomy and Astrophysics on Tuesday (August 17).
Follow Tereza Pultarova on Twitter @TerezaPultarova. Follow us on twitter @Spacedotcom and on Facebook.
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