Astronomers used a combination of low-frequency telescopes, supercomputers and algorithms to create a huge map with 25.000 oversized black holes.
The map shows thousands of dots that look like stars, but are actually huge black holes, each located in a different, distant galaxy.
The researchers located the celestial objects by analyzing the emissions emitted by matter ejected as it approached the black holes.
Every white dot on the map is an oversized one black hole in her own galaxy.
These shows were detected by LOFAR (Low Frequency Array), a huge network of radio telescopes existing at 52 stations in nine European countries.
LOFAR operates at the lowest frequencies that can be observed from Earth. However, its location had a large problem for the study.
LOFAR's observations were distorted by the ionosphere, a shell of free electrons that surrounds the Earth and acts like a cloudy lens above the telescope.
"Είναι παρόμοιο με όταν προσπαθείτε να δείτε ενώ βυθίζετε σε μια πισίνα", αναφέρει ο συν-συγγραφέας of studying Reinout van Weeren του Παρατηρητηρίου του Leiden. "Όταν κοιτάζεις προς τα πάνω, τα κύματα στο νερό της πισίνας εκτρέπουν ακτίνες φωτός και παραμορφώνουν την θέα."
The researchers overcame this challenge by using supercomputers and new algorithms to correct the ionosphere effect every four seconds.
This allowed them to convert radio signals into images.
The new map currently covers 4% of the northern sky, but the astronomers plan to continue their work until they have mapped the entire region.
Eventually, they hope to reveal new ideas about the structure of the universe.