The left picture shows a photo of the quasar, taken by XMM-Newton. The dip in the spectrum of the quasar APM 08279+5255 is caused by the element iron. In a same way that our bones appear dark in X-ray photographs because they are opaque to X-rays, the outflowing iron clouds of APM 08279+5255 are opaque for X-rays that are created at the quasar's centre. At the 'absorption energy' characteristic for iron (marked by the red arrow), some part of the X-ray light is missing.
According to this model, for a well-fed black hole, some part of the matter streaming towards the centre never reaches the black hole but is blown apart in a bipolar, cone-like outflow. This outflow is driven by the strong radiation pressure of the central object. In the case of APM 08279+5255, you are looking along the gas stream which is 'X-rayed' by the central light source.
