Astronomers have detected and measured one of the largest black holes ever observed using a new technique, which should reveal more about the thousands of these cosmic giants that are 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 technique of detection by gravitational lens.
This phenomenon is caused by the presence of an object so massive - a galaxy or a supermassive black hole - that it bends spacetime.
The light coming from a distant source thus appears distorted when it passes nearby.
But while we can observe a galaxy, we literally cannot see a black hole.
This cosmic object has the particularity of being so dense that not even light can escape, which therefore makes it invisible.
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This time, the astronomers were "
", explains to AFP James Nightingale, astronomer at the British University of Durham and first author of the study.
They were able to observe the light of a galaxy located far behind the black hole, and whose path seemed to be deflected by the black hole, about two billion light-years from Earth.
Most galaxies are said to have 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 has ventured too close.
Or by noting their influence on the trajectory of the stars which are in orbit around them.
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, of which at least one is now due to a supermassive black hole.
this landscape is about to change dramatically
,” according to James Nightingale.
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The European Space Agency's Euclid mission, slated for liftoff in July, will usher in "
a big data era
" for black hole hunters by creating a high-resolution map of part of the Universe, adds he.
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 carried out 18 years ago by a Durham University astronomer and colleague of James Nightingale, Alastair Edge, who suspected the presence of a black hole in the center of the galaxy Abell 1201.