An international group of astronomers has published a sky map showing more than 25,000 supermassive black holes. The results of the research were accepted for publication in the journal Astronomy & Astrophysics.

The new map, which depicts 25,000 supermassive black holes, is the most detailed map of the starry sky at low radio frequencies. Astronomers, including scientists from the University of Leiden, used 52 LOFAR stations in nine European countries.

At first glance, it might seem that the sky map contains thousands of stars, but in reality these objects are supermassive black holes. Each black hole is located in a separate distant galaxy.

The new map is the result of years of work on incredibly complex data. We had to invent new methods for converting radio signals into images of the sky.

Study Director Francesco de Gasperin
Long wavelength observations are complicated by the ionosphere surrounding the Earth. This layer of free electrons acts like a cloudy lens that constantly moves around the radio telescope. Study co-author Reynaut van Weeren of the Leiden Observatory explains: “It’s like trying to see the world while plunging into a pool. When you look up, the waves on the water in the pool deflect the light rays and distort the picture. “

The new map was created by combining 256 hours of observations of the northern sky. Researchers have deployed supercomputers with new algorithms that correct for the influence of the ionosphere every four seconds.

The map covers 4% of the northern half of the sky. Astronomers plan to continue until they have mapped the entire northern sky. In addition to supermassive black holes, the map also provides insight into the large-scale structure of the universe.