The LOFAR telescope discovered 13.7 million new objects in the largest radio survey of the universe

New large-scale radio sky survey: LoTSS‑DR3

An international group of astronomers has published the results of the third release (DR3) of the LOFAR Two‑metre Sky Survey – LoTSS. It is the largest catalog of sources in the world, obtained with the European low‑frequency radio telescope LOFAR.

What’s new in LoTSS‑DR3?
Parameter Value
Coverage 88 % of the northern sky
Observing time more than 13 000 hours
Data volume ~18.6 petabytes
Detected sources ~13.7 million new radio sources

These data were processed on a supercomputer at the Jülich Supercomputing Centre (JSC) in Germany.

Key scientific findings
1. Distant galaxies with active nuclei

Most of the detected objects are distant galaxies where supermassive black holes eject powerful relativistic jets. Images often show distortions of “disk‑galaxy” shapes caused by these outflows.

2. Coverage of hidden processes

Radio emission reveals activity of black holes, star‑forming regions, supernova remnants, magnetic fields and galaxy cluster collisions – all that is optically obscured by dust and gas.

3. Low frequencies of LOFAR

Thanks to its ability to penetrate the interstellar medium, LOFAR opens up the inner regions of galaxies and rare extreme phenomena that are inaccessible in visible light.

4. Improvements over previous releases

LoTSS‑DR3 surpasses its predecessors in sky coverage, sensitivity and number of sources, providing a “complete census” of active supermassive black holes to date.

Impact on scientific research
- The data are already being used in hundreds of publications on galaxy evolution, particle acceleration, cosmic magnetic fields and the large‑scale structure of the Universe.

- LoTSS‑DR3 serves as an important prelude to future megaprojects such as the Square Kilometre Array (SKA).

Technical features of LOFAR
LOFAR is a radio interferometer consisting of more than 20 000 antennas (“tiles”) spread across Europe. Its virtual aperture is comparable in size to a continent, requiring enormous computing power and bandwidth (up to 13 Tb/s on individual links).

The SKA project, uniting radio telescopes from Australia to South Africa, will require even greater resources but promises to open new horizons in radio astronomy.

Conclusion: LoTSS‑DR3 demonstrates the power and potential of radio astronomy as a complementary tool to optical and infrared observations, revealing hidden aspects of the Universe and accelerating our understanding of its fundamental processes.