Scientists at NASA have spotted rings around the black hole in an image captured using NASA’s Chandra X-ray Observatory and Neil Gehrels Swift Observatory which reveals a lot of information about the black hole, its companion star, and the intervening dust clouds, says NASA.
“The black hole is part of a binary system called V404 Cygni, located about 7,800 light-years away from Earth. The black hole is actively pulling material away from a companion star — with about half the mass of the Sun — into a disk around the invisible object. This material glows in X-rays, so astronomers refer to these systems as “X-ray binaries,”the US space agency said
Neil Gehrels Swift Observatory discovered a burst of X-rays from V404 Cygni creating high-energy rings in 2015 between June 30 and August 25. These rings were generated during a phenomenon called light echoes. Cosmic dust consists of tiny, solid particles.
Black holes are regions in space-time where gravity’s pull is so powerful that not even light can escape its grasp. However, while light cannot escape a black hole, its extreme gravity warps space around it, which allows light to “echo,” bending around the back of the object, a therory which Albert Einstein proposed
“The rings tell astronomers not only about the black hole’s behavior, but also about the landscape between V404 Cygni and Earth. For example, the diameter of the rings in X-rays reveals the distances to the intervening dust clouds the light ricocheted off. If the cloud is closer to Earth, the ring appears to be larger and vice versa. The light echoes appear as narrow rings rather than wide rings or haloes because the X-ray burst lasted only a relatively short period of time.”NASA further added
The researchers compared the X-ray spectra or the brightness of X-rays over a range of wavelengths to computer models of dust with different compositions thus exploring the properties of dust cloud around the black hole. The researchers believe the dust clouds likely contains mixtures of graphite and silicate grains.
The study also found that the densities of all dust clouds are not uniform in all directions after analyzing the inner rings.
Meanwhile, the result is related to a similar finding of the X-ray binary Circinus X-1, which contains a neutron star rather than a black hole, published in a paper in the June 20, 2015, issue of The Astrophysical Journal, titled, “Lord of the Rings: A Kinematic Distance to Circinus X-1 from a Giant X-Ray Light Echo” (preprint). This study was also led by Sebastian Heinz.