First evidence that ‘dive zones’ exist around black holes in space

An international team led by researchers from Oxford University Physics has proven Einstein right in an important prediction about black holes. Using X-ray data to test Einstein’s theory of gravity, their research provides the first observational evidence that a ‘dive zone’ exists around black holes: a region where matter stops orbiting the hole and instead falls straight in. Furthermore, the team found that this region exerts some of the strongest gravitational forces yet identified in the Milky Way. The findings were published in Monthly notices of the Royal Astronomical Society.

The new findings are part of extensive research into remarkable mysteries surrounding black holes by astrophysicists at Oxford University Physics. This study focused on smaller black holes relatively close to Earth, using X-ray data collected by NASA’s space-based Nuclear Spectroscopic Telescope Array (NuSTAR) and Neutron star Interior Composition Explorer (NICER) telescopes. Later this year, a second Oxford team hopes to get closer to recording the first videos of larger, more distant black holes as part of a European initiative.

Unlike Newton’s theory of gravity, Einstein’s theory states that close enough to a black hole it is impossible for particles to safely follow circular orbits. Instead, they quickly “dive” toward the black hole, almost at the speed of light. The Oxford study has investigated this area in depth for the first time, using X-ray data to gain a better understanding of the force generated by black holes.

“This is the first look at how plasma, peeled from the outer edge of a star, undergoes its final fall into the center of a black hole, a process that takes place in a system about ten thousand light-years away,” said Dr. Andrew Mummery. , from Oxford University Physics, who led the study. “What’s really exciting is that there are many black holes in the Milky Way, and we now have a powerful new technique to use them to study the strongest known gravitational fields.”

“Einstein’s theory predicted that this definitive jump would exist, but this is the first time we have been able to demonstrate this happening,” continued Dr. Mummery. “Think of it as a river turning into a waterfall. So far we’ve been looking at the river. This is our first view of the waterfall.”

“We believe this represents an exciting new development in the study of black holes, allowing us to probe this final region around them. Only then can we fully understand gravity,” Mummery added. ‘This final plasma burst takes place at the very edge of a black hole and shows that matter responds to gravity in its strongest possible form.’

Astrophysicists have been trying to understand what’s happening close to the black hole’s surface for some time, and they do this by studying disks of material that orbit it. There is a final region in spacetime, known as the diving region, where it is impossible to stop a final descent into the black hole and the surrounding fluid is effectively doomed.

There has been debate among astrophysicists for decades about whether the so-called diving region would be detectable. The Oxford team has been developing models for this in recent years and in the just-published study shows the first confirmed detection found using X-ray telescopes and data from the International Space Station.

While this research focuses on small black holes closer to Earth, a second research team from Oxford University Physics is part of a European initiative to build a new telescope, the Africa Millimeter Telescope, which will further improve our ability to take direct images of creating black holes would increase enormously. . More than €10 million in funding has already been secured, part of which will support several first doctorates in astrophysics for the University of Namibia, working closely with the team at Oxford Physics University.

The new telescope is expected to enable observation and filming of large black holes in the center of our own galaxy, but also far beyond, for the first time. As with small black holes, large black holes are expected to have a so-called ‘event horizon’, where material from space is dragged towards their center in a spiral as the black hole spins. These represent almost unimaginable sources of energy and the team hopes to observe and film them for the first time.

The study “Continuum emission from the diving region of black hole disks” was published in Monthly Notices of the Astronomical Society.