Astronomers have detected and measured one of the largest black holes ever observed, using a new technique that should reveal more about the thousands of these cosmic giants expected to be discovered in the coming years.
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 thanks to the gravitational lens detection technique.
This phenomenon is caused by the presence of such a massive object, a galaxy or a supermassive black hole, that it bends space-time. Light coming from a distant source therefore appears distorted when it passes close by.
But while we can see a galaxy, we literally can’t see a black hole. This cosmic object has the particularity of being so dense that not even light can escape, making it invisible.
This time, the astronomers were “very lucky,” James Nightingale, an astronomer at the University of Durham in the United Kingdom, and first author of the study, told Agence France-Presse (AFP).
They were able to observe light from a galaxy located far behind the black hole, and whose path seemed to be deflected by the black hole, some two billion light-years from Earth.
It is said that most galaxies have a black hole at their center, but until now, to detect its presence it was necessary to observe the energy emissions produced by absorbing matter that ventured too close, or to observe its influence on the trajectory. of the galaxy. stars orbiting around it.
These techniques, however, only work for black holes close enough to Earth.
The gravitational lens technique allows astronomers to “discover black holes in 99% of galaxies that are currently inaccessible” to traditional observation, because they are very distant, the astronomer stressed.
There are about 500 gravitational lenses, but “this picture is about to change dramatically,” according to James Nightingale.
The European Space Agency’s Euclid mission, scheduled to launch in July, will usher in “an era of ‘big data’ [megadados]for black hole hunters, creating a high-resolution map of part of the Universe, the scientist added.
According to Nightingale, in six years of observation, Euclid will be able to 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 taken by the Hubble Space Telescope.
These observations confirm and explain simulations carried out 18 years ago by a Durham University astronomer and James Nightingale’s colleague Alastair Edge, who suspected the presence of a black hole at the center of the Abell 1201 galaxy.
Source: TSF
