Can Compton scattering increase the energy of photons?

[jim421616]

I've read (in Hagai Netzer's book The Physics and Evolution of Active Galactic Nuclei) that "Comptonization in the [black hole's accretion] disk atmosphere can increase the energy of some photons..."

I thought Compton scattering could only decrease a photon's energy. What am I missing?

 

[Vanadium 50]

The electrons are moving.