How a Black Hole's Corona Stretched Out in an Hour
The XMM-Newton X-ray telescope stared at galaxy Mrk 1044 for two straight hours. Inside it, a black hole is surrounded by a swirling disk of superheated gas. This gas glows in X-rays, and its light flickers — brighter, then dimmer.
For the first half hour, the flickering of soft and hard X-rays was in step.