Fig. LoTSS-DR2 image of the radio galaxy NGC 315.
More than 4.4 million radio sources from the LOFAR Two-metre Sky Survey were released in February 2022 by an international collaboration including scientists from GLOW member institutes. The team surveyed more than a quarter of the northern sky using the Low Frequency Array (LOFAR) at a frequency 120-168 MHz. This already second data release presents about a million objects that are completely new discoveries and close to four million objects that were seen at radio wavelengths for the first time. Most of the radio sources are outside the Milky Way and are either galaxies that harbour massive black holes or are rapidly growing new stars. Rarer objects that have been discovered include colliding groups of distant galaxies and flaring stars within the Milky Way.
The release is the result of almost seven year of observations (2014 - 2020) and of extended data processing on high performance computers all over Europe. The observational data occupied about 8 petabytes of disk space - the equivalent to the storage capacity of several ten thousand desktop computers. "To process the enormous amounts of data supercomputing resources are required. We use the JUWELS supercomputer at the FZ Jülich. As reward we obtain the sky maps full of the fantastic radio galaxies and many more spectacular radio features." explains Matthias Hoeft from the Thüringer Landessternwarte.
Research Report: Shimwell et al. (2022)