This supermassive black hole has a mass equivalent to more than 30 billion times that of the sun, according to the study published this week in a scientific journal of the British Royal Astronomical Society.

It is the first whose characteristics are determined through the gravitational lens detection technique. This phenomenon is caused by the presence of an object so massive -- a galaxy or a supermassive black hole -- that it bends space-time. Light from a distant source appears distorted when it passes nearby.

But if you can observe a galaxy, you cannot, literally, see a black hole. This cosmic object has the particularity of being so dense that even light cannot escape, which makes it invisible.

This time, the astronomers were "very lucky," James Nightingale, an astronomer at Britain's Durham University and first author of the study, told AFP. They were able to observe the light of a galaxy located far behind the black hole, and whose path seemed deflected by the black hole, about two billion light-years from Earth.

Most galaxies are thought to harbor a black hole at their center. But until now, to detect their presence, it was necessary to observe the energy emissions they produce by absorbing matter that ventured too close. Or by noting their influence on the trajectory of the stars that orbit them.

100,000 lenses

These techniques, however, only work for black holes close enough to Earth.

The gravitational lensing technique allows astronomers to "discover black holes in the 99% of galaxies that are currently inaccessible" to traditional observation, because they are too far away, says the astronomer.

There are about 500 gravitational lenses, at least one of which is now the result of a supermassive black hole. But "this landscape is about to change dramatically," according to James Nightingale.

The European Space Agency's Euclid mission, scheduled for liftoff in July, will usher in "an era of big data" for black hole hunters, creating a high-resolution map of part of the universe, he added.

According to the scientist, in six years of observation, Euclid could detect up to 100,000 gravitational lenses, including potentially several thousand black holes.

The discovery made by the astronomer and his colleagues was based on computer simulations and images obtained by the Hubble Space Telescope.

These observations confirm and explain those made 18 years ago by Durham University astronomer and James Nightingale's colleague, Alastair Edge, who suspected the presence of a black hole at the centre of the galaxy Abell 1201.

© 2023 AFP