Cross section of the Shakura–Sunyaev accretion disk geometry viewed edge-on, ﹩\theta =\frac{\pi }{2}﹩ and ϕ = 0. The black hole is shown at the center of the disk geometry, and h_c denotes the height of the lamppost corona above the disk. Note that this plot has no associated units, and is intended only to illustrate the basic configuration of the system.