NASA is observing a black hole that is part of a binary system called V404 Cygni. The system is 7,800 light-years from Earth, and the black hole is actively consuming dust and material from its companion star. The companion star’s mass is about half the mass of the Sun.
Although we cannot see the black hole itself, the material it collects from its companion star has formed into a disk around the black hole. The disc is visible because it glows in X-rays, which has led to the name X-ray binars. An X-ray burst from V404 Cygni was detected on June 5, 2015 by the Swift Observatory.
As a result of the flash, high-energy rings were formed, resulting from the so-called light echo. The light echo originated when X-rays from the black hole bounced off the dust clouds between V404 Cygni and Earth. NASA notes that dust clouds in space are not like dust you can sweep around your home, but more like smoke made up of tiny particulate matter.
The image above is a new composite X-ray image with Chandra X-ray data highlighted in blue and PAN-STARRS optical data showing stars in the field of view. The NASA image shows concentric rings created by X-rays emitted by V404 Cygni flares observed in 2015, reflected from various dust clouds.
The NASA image is simplified to show only four of the eight rings. Scientists analyzed 50 observations made with Swift in 2015 between June 30 and August 25. Chandra observed the system from 11 to 25 July of that year. The rings are interesting because they allow astronomers to learn more about the black hole’s behavior and the landscape between V404 Cygni and Earth.
NASA says the diameter of the rings in the X-rays emphasizes the distance to dust clouds that light falls on. When the cloud is closer to the Earth, the rings appear larger, and vice versa. Narrower rings indicate that the X-ray burst lasted for a shorter period of time compared to wider rings.