Data-Intensive Radio Astronomy: JUWELS Contributes to the Most Detailed Map of the Northern Sky to Date
For more than a decade, an international team of radio astronomers observed the northern sky using the LOFAR (Low Frequency Array) radio telescope. With its third major data release, LOFAR has now published the most comprehensive radio map of active galaxies to date. The catalogue contains 13.7 million cosmic radio sources, including active galactic nuclei, merging galaxy clusters, and rare supernova remnants. The results have been published in the journal Astronomy & Astrophysics.
In addition to Forschungszentrum Jülich, which hosts the LOFAR station DE605, and the Jülich Supercomputing Centre, which provides the JUWELS supercomputer, the survey involved universities in Germany, the Netherlands, Poland, France, Ireland, Latvia, Sweden, and the United Kingdom, as well as the Thüringer Landessternwarte. Around 13,000 observation hours were analysed for the most detailed sky survey to date (LOFAR Two-metre Sky Survey, LoTSS).
Radio Telescope Provides Insights into the Invisible Universe
Observations at low radio frequencies offer a completely different view of the cosmos compared with optical telescopes. Energetic phenomena invisible to the human eye, such as jets from supermassive black holes or galaxies undergoing intense star formation, can be detected. Rare or otherwise hard-to-observe objects – from merging galaxy clusters to faint supernova remnants – can also be studied in detail.
Data Processing at the Highest Level
The analysis of around 13,000 observation hours required highly complex data processing across multiple European centres. The raw data were calibrated, corrected for ionospheric distortions, and archived permanently – a technically demanding process in which the JSC, with its JUWELS modular supercomputer, played a major role alongside computing resources of partner institutions.
On JUWELS, complex calibration and imaging pipelines were implemented and executed over millions of core hours. The precise correction of atmospheric effects, as well as the automated identification and cataloguing of millions of radio sources, required a highly scalable HPC architecture with fast data connectivity and sustainable archiving. Today, the LOFAR archive is among the largest astronomical data collections in the world.
“For the first time in an astronomical observation project, data of this magnitude has been stored, processed, and made publicly available. The LoTSS sky survey sets new standards and paves the way for future large-scale projects,” says Cristina Manzano, Head of ODT Technical Services at the JSC.
Strategic Importance for Germany and Europe
The publication demonstrates the strength of integrated European research infrastructures – from distributed telescope stations to high-performance supercomputers and long-term data archives. In doing so, the JSC reinforces Germany’s role in European radio astronomy. The methods developed in the context of LOFAR also serve as a reference for future data-intensive large-scale projects and contribute to Europe’s international competitiveness in astrophysics.
About LOFAR ERIC
LOFAR (Low Frequency Array) is a radio telescope developed by the Netherlands Institute for Radio Astronomy (ASTRON). It consists of thousands of simple antenna elements distributed across Europe and connected via fibre-optic networks. The data from all antennas are combined using high-performance computing to create highly detailed images of the radio sky.
LOFAR is operated by the LOFAR European Research Infrastructure Consortium (LOFAR ERIC), a collaboration of institutions from eleven countries. The consortium pools expertise, infrastructure, and computing resources across national borders, enabling cutting-edge research on the formation and evolution of the Universe. The LOFAR archive is now one of the largest astronomical data collections worldwide.
In Germany, LOFAR data are used in research networks such as the Excellence Cluster Quantum Universe and the DFG research group FOR 5195 Relativistic Jets in Active Galaxies. Within the framework of the GLOW consortium (German Long Wavelength), six universities, the Jülich Research Centre, the Leibniz Institute for Astrophysics Potsdam, the Max Planck Institute for Astrophysics, the Max Planck Institute for Radio Astronomy, and the Thüringer Landessternwarte Tautenburg are involved in operating the six German LOFAR stations.
Further Information
- Press release from the Tautenburg Observatory: Comprehensive Map of the Radio Sky Published
- News Release from FZJ: LOFAR Releases Largest Radio Sky Map
- Scientific Publication: „The LOFAR Two-metre Sky Survey VII. Third Data Release”, T.W. Shimwell et al., 2025, in: Astronomy & Astrophysics DOI: 10.1051/0004-6361/202557749
- Previous news from Forschungszentrum Jülich: LOFAR Radio Telescope Becomes European Research Facility
Contact
Cristina Manzano
Head of ODT Technical Services
- Jülich Supercomputing Centre (JSC)
Room 226