Though it has been theoretically suggested for some time that a dark matter density spike could form around a black hole, there hasn’t been any strong evidence to back it up.
However, astronomers at the Education University of Hong Kong have reported finding dark matter density increases surrounding A0620-00 and XTE J1118+480, two nearby black holes.
“We identified two close black holes (A0620-00 and XTE J1118+480) in binary systems,” astronomers Man Ho Chan and Chak Man Lee of Education University of Hong Kong stated.
The rates of orbital decay of the partner stars, based on their orbits, are estimated to be around one millisecond (1 ms) annually, which is around 50 times higher than the theoretical estimate of approximately 0.02 ms yearly. We used computer simulations to apply the “dark matter dynamical friction model” to the A0620-00 and XTE J1118+480 systems in order to investigate the possibility of dark matter surrounding black holes.
The rapid orbital degradation of the partner stars, according to the authors, matched the observational data exactly.
Notably, this provides indirect proof that the presence of dark matter around black holes can cause a large amount of dynamical friction, which lowers the companion stars’ orbital speed.
The results constitute a breakthrough in the study of dark matter, as they validated a theoretical idea that was formulated in the late 20th century.
The idea was that dark matter that was near enough to black holes would be ingested, with the leftovers being redistributed.
Eventually, a density spike surrounds the black holes as a result of the process.
In a manner akin to drag force, “such a high density of dark matter would create dynamical friction to the companion star,” explained Dr. Chan.The “dynamical friction model” is being applied for the first time in this work to support and demonstrate the existence of dark matter around black holes.
The study offers a significant new avenue for further investigation into dark matter. Previous investigations on the existence of dark matter, which mostly used gravitational wave detection and gamma rays, were dependent on the occurrence of unusual events like the merger of two black holes.
Astronomers may have to wait a while for it to happen. But these restrictions will no longer apply to the unique technique.There are at least eighteen binary systems similar to our research subjects in the Milky Way alone, which can offer rich information to assist solve the enigma of dark matter.
