Artist's impression of black-hole system
This artist's impression depicts the accretion disc surrounding a black hole, in which the inner region of the disc precesses.
In these three views, the precessing inner disc shines high energy radiation that strikes the matter in the surrounding accretion disc, causing the iron atoms in that disc to emit in X-rays, depicted as the glow on the accretion disc to the right (in view a), to the front (in view b) and to the left (in view c).
A study, using data from ESA's XMM-Newton X-ray Observatory and NASA's NuSTAR telescope, measured this 'wobble' in the iron line X-ray emission, and interpreted this as evidence for the Lense-Thirring effect in the strong gravitational field of a black hole.