Gordon.  
The results of this equation only become important when the bulk Lorentz factor is greater than 103 in the radiative deceleration of relativistic jets in active galactic nuclei. When the effect that this equation is most associated with occurs in a magnetic field, the deviation from this equation results in an oscillation in the spectral distribution, which is inversely proportional to one minus the quantity Beta times the cosine of the critical angle between the initial momenta of an electron and a photon.  It produces a sharp maximum in the shortwave region due to the emission of very hard gamma-quanta from the collision of optical and x-ray photons with non-relativistic electrons. Reproducing the Thomson result for low-energy photons, one of its namesakes co-developed a relativistic form of the Schrodinger Equation with Walter ?Gordon.  For 10 points, name this doubly-eponymous equation which produces the differential cross-section of high energy photons in Compton Scattering.
The results of this equation only become important when the bulk Lorentz factor is greater than 103 in the radiative deceleration of relativistic jets in active galactic nuclei.
{Klein}-{Nishina Formula}