A spectacular set of rings around a black hole has been captured using NASA’s Chandra X-ray Observatory and Neil Gehrels Swift Observatory. The X-ray images of the giant rings have revealed new information about dust located in our Galaxy, using a similar principle to the X-rays performed in doctor’s offices and airports.
The black hole in V404 Cygni is actively pulling material away from a companion star — with about half the mass of the Sun — into a disk around the invisible object. A burst of X-rays from the black hole detected in 2015 created the high-energy rings from a phenomenon known as light echoes, where light bounces off of dust clouds in between the system and Earth. In these images, X-rays from Chandra are shown, along with optical data from the Pan-STARRS telescope that depict the stars in the field of view. Each of the concentric rings is created by the burst of X-rays reflecting off dust clouds at different distances. The rings are shown incomplete, with gaps at the upper left, upper right, and middle areas. These gaps show the edges of Chandra’s field of view during the observations, or the sections of the field Chandra did not observe.
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This artist’s illustration shows in detail how the ringed structure seen by Chandra and Swift is produced. Each ring is caused by X-rays bouncing off of different dust clouds. If the cloud is closer to us, the ring appears to be larger. The result is a set of concentric rings with different apparent sizes depending on the distance of the intervening cloud from us.
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Illustration
(Credit: Univ. of Wisconsin-Madison/S.Heinz)
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.
Saurce: nasa.gov