The Thermal History of the Universe and the Spectrum of Relic Radiation

TLDR: In this article, it is shown that the absence of noticeable deviations from the Planckian spectrum enables us to set limits to the energy release in the early universe (102 < z < 108).

Abstract: Many of the cosmological models currently under discussion and theories of the origin of galaxies which involve antimatter, strong turbulence and so on result in significant energy release during the evolution of the Universe. It is evident that significant energy production should lead to distortions of the spectrum of the relic radiation. The absence of noticeable deviations from the Planckian spectrum enables us to set limits to the energy release in the early Universe (102 < z < 108). But in order to have a clear picture of possible distortions, let us first review the idealized situation.