This supermassive black hole has a mass equivalent to more than 30 billion times the mass of the Sun, according to the study published this week in a scientific journal of Britain’s Royal Astronomical Society.
It is the first whose properties are determined thanks to the detection technique through gravitational lensing. This phenomenon is caused by the presence of an object so massive – a galaxy or a supermassive black hole – that it warps spacetime. Light coming from a distant source therefore appears distorted when it passes close by.
But while we can observe a galaxy, we literally cannot see a black hole. This cosmic object has the peculiarity of being so dense that not even light can escape, therefore making it invisible.
This time, the astronomers were “very lucky,” James Nightingale, an astronomer at Britain’s Durham University and lead author of the study, told AFP. They were able to observe light from a galaxy that is far beyond the black hole and whose orbit appears to be deflected by the black hole, about two billion light-years from Earth.
It is said that most galaxies have a black hole at their center. But to detect their presence, until now it has been necessary to observe the energy emissions they produce by absorbing matter that has dared to get too close. Or by noting their influence on the trajectories of the stars orbiting them.
100,000 lenses
However, these techniques only work for black holes that are close enough to Earth.
The gravitational lensing technique allows astronomers to “detect black holes in the 99% of galaxies that are currently inaccessible to traditional observation” because they are too distant, says the astronomer.
There are about 500 gravitational lenses, at least one of which is now attributed to a supermassive black hole. But “this landscape will change dramatically,” said James Nightingale.
The European Space Agency’s Euclid mission, scheduled for launch in July, will usher in “a big data era” for black hole hunters by producing a high-resolution map of part of the universe, he adds.
According to the scientist, in six years of observation, Euclid was able to detect up to 100,000 gravitational lenses, including possibly several thousand black holes.
The astronomer and his colleagues’ discovery was based on computer simulations and images from the Hubble Space Telescope.
These observations confirm and explain those made 18 years ago by a Durham University astronomer and colleague of James Nightingale, Alastair Edge, who suggested the presence of a black hole at the center of the galaxy Abell 1201.