Astronomers have unveiled the sharpest and most sensitive low-frequency radio image of the sky ever made — a picture covering a patch of sky about 25 times the size of the full Moon, containing almost 63,000 hidden galaxies.
The image was made with LOFAR, the Low Frequency Array, by an international team led by Leiden University and Leiden Observatory with ASTRON, the Netherlands Institute for Radio Astronomy. The lead author is J. M. G. H. J. de Jong. The field, known as ELAIS-N1 in the northern sky, covers about 2.5 by 2.5 degrees, and the catalogue lists 62,916 unique sources — press coverage rounds it to “almost 63,000” — mostly active galactic nuclei and star-forming galaxies.
Twenty times sharper
The new image is 20 times sharper than the previous most sensitive LOFAR image of the same field, at a resolution of 0.3 arcseconds — likened to spotting a coin from about 10 kilometres away. It is an 8-billion-pixel image built from 200 hours of data, 400 terabytes in total, at frequencies of 115 to 168 MHz, with a centre sensitivity of 5.3 microJansky per beam.
The work has been accepted for publication in Astronomy & Astrophysics, with a preprint posted on 4 November 2026, and the data have been released publicly.
Galaxies you cannot see
Most of the 63,000 sources are galaxies that optical telescopes cannot see — their light is hidden behind dust, or they shine brightest in radio waves. A radio image like this one is a census of the invisible universe: galaxies forming stars, black holes feeding, and objects that would otherwise stay hidden.
The sharpness matters because it lets astronomers tell the sources apart. In a blurry radio image, galaxies blend together. In this one, at 0.3 arcseconds, they stand alone — 62,916 of them, in a patch of sky you could cover with your thumbnail held at arm’s length. The universe, it turns out, is crowded. We just needed a sharper picture to see it.
The data are public, which means the census does not belong to one team. Any astronomer can now work through the 62,916 sources, sorting the star-forming galaxies from the active nuclei, and finding the objects that do not fit either category. The image took 200 hours to make. The work it enables will take years — and it starts with a picture sharper than any low-frequency radio image made before it.
