Some 7,800 light years from Earth, a black hole is actively sucking in material from a companion star with about half the mass of the Sun. The material forms a disc around the black hole, glowing in X-rays as particles crash together in a swirling inferno. The binary system is known as V404 Cygni and on 5 June 2015, the Swift space telescope detected an X-ray outburst that created a spectacular ring of “light echoes” as the high-energy radiation bounced off intervening clouds of smoke-like interstellar dust. In the composite image below, observations by the Chandra X-ray Telescope (shown in blue) were combined with optical imagery from the Pan-STARRS telescope in Hawaii. Eight concentric X-ray echoes can be seen as radiation reflects off dust at different distances.
The rings are not complete because V404 Cygni was placed between the telescope’s detectors, out of view, to avoid possible damage should another outburst occur during the observation. This illustration below shows the fields of view used for the observations.