With new algorithms and supercomputers, an extremely detailed radio map of the universe was created. Now astronomers can have a look at radio knowledge of galaxies with far more precision. This was revealed in Nature Astronomy by Leiden PhD scholar Frits Sweijen and colleagues.
“This single map has almost as many pixels as previous maps of the entire sky had,” says Frits Sweijen, PhD scholar at Leiden Observatory. The researchers solved the blurring impact of UV radiation in our environment: with particular software program they managed to appropriate for this interference. Supercomputers in Leiden and Amsterdam used their monumental computing energy to make sure that this additionally went pretty shortly.
Five by 5 full moons
Within the foreseeable future, the brand new technique may subsequently convey your complete northern sky into sharp focus. Now the researchers present solely a small half, Sweijen explains: “Suppose you see a square of five by five full moons in the sky. From that cube of space, we made a map of almost 7 billion pixels, on which almost 2,500 galaxies are sharply visible.”
The 4 galaxies on the left within the picture are a lot sharper in deal with the brand new map (proper). Credit: Leiden University
Cell cellphone on Mars
Sweijen: “The map of space was made on the basis of radio waves that we captured from space with the International LOFAR Telescope. This is an enormous radio telescope with tens of thousands of antennas spread across a European area with a diameter of 2000 kilometers. Those antennas listen for cosmic radio rays.”
He continues: “Because of its monumental space and plenty of antennas, LOFAR can ‘see’ radiation in beautiful element, with a sensitivity that might even can help you detect a cellular phone on Mars.” The data from the telescope can be seen by humans after translation by a computer into a radiation map, a kind of photograph.
Waves smear the signal
One problem with taking sharp universe pictures with LOFAR is the UV radiation from the sun. This clouds our atmosphere with charged particles, ions. This ionosphere disturbs radio waves from space before the telescope picks them up. Sweijen: “This makes it seem as if LOFAR is observing the sky from the seabed, where the waves smear the signal. Software recently developed by the Netherlands Institute for Radio Astronomy ASTRON corrected the measured radiation over the entire area. This allowed us to focus and map LOFARs entire field of view.”
“We can now study the evolution of black holes and the galaxies in which they are found in greater detail than before.”
The software works with algorithms that require a lot of computer power. That was available. In Leiden, the recently built Academic Leiden Interdisciplinary Cluster Environment (ALICE) provided its computing power. In Amsterdam, ICT cooperation SURF provided early access to their new Spider platform, which has been specially set up for data-intensive projects such as this research.
Next plan: the entire northern sky
The data correction of the LOFAR field of view was done in 25 sections, each one full moon in size. This took seven days per area. On a single computer, it would have taken 7 times 25, or 175 days, to create the entire map. Thanks to the large-scale infrastructure of SURF and Leiden with parallel computing power, it took only seven days. That means there is now a fast way to eventually map the entire Northern sky in comparable detail, something Sweijen says could begin in the next few years.
“We can now study the evolution of black holes and the galaxies in which they are found in greater detail than before,” he says. “Galaxies in the earlier universe, for example, which due to their distance or young age were previously too small to see in any detail, can now be seen sharply by the thousands.”
Reference: “Deep sub-arcsecond wide-field imaging of the Lockman Hole field at 144 MHz” by F. Sweijen, R. J. van Weeren, H. J. A. Röttgering, L. K. Morabito, N. Jackson, A. R. Offringa, S. van der Tol, B. Veenboer, J. B. R. Oonk, P. N. Best, M. Bondi, T. W. Shimwell, C. Tasse and A. P. Thomson, 27 January 2022, Nature Astronomy.
DOI: 10.1038/s41550-021-01573-z
