An Etymological Dictionary of Astronomy and Astrophysics

The loss of energy by high-energy electrons in a → galaxy cluster, which distorts the → cosmic microwave background (CMB) radiation through → inverse Compton effect. When photons from the CMB radiation travel through a hot plasma (with a temperature of around 10⁸ K), in which bathe a galaxy cluster, they collide with energetic electrons and some of the energy of the electrons is transferred to the low energy CMB photons. If we look at the CMB radiation through such a plasma cloud, we therefore see fewer microwave photons than we would if the cloud were not there.

See also: Named after Rashid Sunyaev (1943-) and Yakov Borisovich Zel’dovich (1914-1987), Russian astrophysicists; → effect.