First evidence that 'sink regions’ exist around black holes in space

An international team led by Oxford University physics researchers has proved that Einstein was right about a key prediction about black holes. Using X-ray data to test Einstein’s theory of gravity, their study provides the first observational evidence that a „plow-out” exists around black holes: a region that stops orbiting the hole and falls straight in. Also, the team found This region exerts some of the strongest gravitational forces ever identified in the galaxy. The findings are published Monthly Notices of the Royal Astronomical Society.

The new findings are part of a wider range of investigations into the great mysteries surrounding black holes by astrophysicists at Oxford University Physics. The study focused on supermassive black holes closest to Earth, using X-ray data collected from 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 massive, more distant black holes as part of a European effort.

Unlike Newton’s theory of gravity, Einstein’s theory states that it is impossible for particles close enough to a black hole to follow circular orbits. Instead, they „cry” toward the black hole at near the speed of light. The Oxford study assessed this region in depth for the first time, using X-ray data to better understand the power generated by black holes.

„This is the first look at how plasma ejected from the outer edge of a star receives its final plunge into the center of a black hole, in a system tens of thousands of light-years away,” said Dr Andrew Mummery. , an Oxford University physicist who led the study. „What’s really exciting is that there are so many black holes in the galaxy, and we now have a powerful new technique to use them to study the known strong gravitational fields.”

„Einstein’s theory predicted that there would be this final collapse, but this is the first time we’ve demonstrated that it happens,” Dr Mummery continued. „Think of it like a river turning into a waterfall — so far, we’ve been looking at the river. This is the first glimpse of the waterfall.”

„We believe this represents an exciting new development in the study of black holes, allowing us to explore this final region around them, where gravity can be fully understood,” Mummery added. „This final collapse of the plasma occurs at the edge of the black hole and shows matter responding to gravity in its strongest form.”

Astrophysicists have been trying for some time to understand what happens near the surface of black holes, and to do this by studying the disks of material that surround them. There is a final region of spacetime, known as the sink region, where it is impossible to stop the final descent into the black hole and the surrounding fluid is effectively destroyed.

For decades, astrophysicists have debated whether the so-called sinking region can be detected. The Oxford team has been developing models for it for the past two years, and the study, now published, demonstrates the first confirmed detection using X-ray telescopes and data from the International Space Station.

While this study focuses on small near-Earth black holes, a second research team from Oxford University Physics is part of a European effort to build the Africa Millimeter Telescope, which will greatly improve the ability to produce direct images of black holes. . Over €10 million in funding has already been secured, part of which will support several first PhDs in astrophysics for the University of Namibia, working closely with the University of Oxford Physics team.

The new telescope is expected to help observe and image supermassive black holes at the center of our own galaxy and beyond for the first time. Like smaller black holes, larger black holes are expected to drag material toward their core in a spiral from space as the black hole spins, called an „event horizon.” These represent unimaginable sources of energy and the team hopes to observe and film them spinning for the first time.

The study, „Coherent emission from the plunging region of black hole disks,” is published in the Monthly Notices of the Astronomical Society.