Researchers have figured out how to recreate the environment near a black hole in order to understand the processes that cause them to emit high energy X-rays.
Black holes are famous for having a gravitational field that is so potent that light cannot escape its pull. But that same gravitational pull causes nearby matter to reach energies that results in a prodigious amount of radiation, from regular light up to X-rays and beyond. Researchers have attempted to model the behavior of matter as it gets drawn into accretion disks near a black hole in order to understand this radiation, but the conditions in these areas are difficult to reproduce on Earth. Now, a consortium of researchers from China, Japan, and Korea have figured out how to use a 300 GigaWatt laser to reproduce conditions near the accretion disk, and have successfully reproduced the spectrum observed near both black holes and neutron stars.
In many cases, black holes and neutron stars form in binary systems, and their intense gravitational pull can be sufficient to strip matter off their companion star. That matter gets drawn into a disk of gas centered on the black hole, where some of it is slowly dragged into the black hole. This process can produce luminous jets of matter that move at close to the speed of light as it exits the system along magnetic field lines that extend from the poles of the black hole. Within the disk itself, the matter nearest the black hole is heated by energetic collisions as it’s drawn towards the event horizon. The light from that matter also ionizes the material towards the outer edge of the disk, resulting in high energy radiation that we can detect using equipment like the space-based Chandra X-ray Observatory.
As a result of the more detailed measurements, the authors have produced results that suggest astronomers may have been feeding their models a variable that’s not entirely reflective of physical reality. The variable is supposed to reflect a combination of the radiation intensity and target density, and astronomers have assumed a range of typical values. Using this experimental system, however, the authors’ have come up with a number that’s outside the range used by astronomers.
It’s important to note that this isn’t a difference between experimental data and models. The authors of the new paper still had to use a model to understand what was happening in their sample to produce the spectrum they observed. The difference is that they were able to feed their model data with a much higher precision, and understood the conditions that produced the data lot better.