Discovery of 'cosmic monster' weighing 36 billion times more than the Sun

According to research published in the journal Monthly Notices of the Royal Astronomical Society, this giant black hole has an estimated mass of about 36 billion times that of the Sun, nearly reaching the maximum theoretical limit of black holes in the universe.

“It is in the top 10 largest black holes ever discovered, and very possibly the largest,” said Thomas Collett, a researcher from the University of Portsmouth.

Giant black hole at the center of the "Cosmic Horseshoe"

The black hole is located about 5 billion light-years from Earth, at the center of one of the largest known galaxies, the Cosmic Horseshoe Galaxy. Its massive size warps space and time, deflecting and bending light from another galaxy.

To detect and accurately measure the size of this "cosmic monster", scientists had to develop a completely new method.

"Most previous measurements of black hole masses were indirect and had large uncertainties, so we weren't really sure which one was the biggest. But with this new method, we have much higher confidence in the mass of this black hole," explained researcher Collett.

The team looked for signs of gravitational lensing, a phenomenon where the gravity of a massive object bends and distorts light from a light source behind it, acting like a natural lens.

In parallel, they applied the "gold standard" method in astronomy: studying the motion of stars in the galaxy, their speed and how they orbit to infer the mass of the black hole.

However, this method is only effective for relatively nearby galaxies. By incorporating data from gravitational lensing, scientists have extended their measurement capabilities to much more distant regions of the universe.

"The combined approach of strong gravitational lensing and stellar dynamics will provide more direct and reliable measurements, even for very distant systems," said co-author Carlos Melo from the Federal University of Rio Grande do Sul in Brazil. "What is particularly exciting is that this method allows the detection and measurement of the masses of 'hidden' supermassive black holes in the universe, even when they are completely silent."

Products of galactic mergers

Researchers believe the supermassive black hole formed when two galaxies merged. Cosmic Horseshoe is a “fossil galaxy,” the final state when two nearby galaxies merge into one giant entity, with no other bright galaxies around.

"It is likely that all the supermassive black holes that existed in the component galaxies also merged to form the supermassive black hole we have just discovered. So we are witnessing the final stages of galaxy and black hole formation," said researcher Collett.

The team hopes to apply the method to data collected by the European Space Agency's Euclid telescope to find more supermassive black holes and the galaxies they contain. The ultimate goal is to better understand the role black holes play in suppressing new star formation in galaxies.