Study of the cosmic microwave background radiation (CMBR) was advanced especially over the last ten years. The observed CMBR spectrum may be fitted by the planck function at the temperature T=2.725±0.001 K with relative accuracy 10-4. It means that radiation as well as the baryonic matter were under thermodynamical equilibrium at the begining of the epoch of the primordial plasma recombination.
Nevertherless, the CMBR spectrum has to be a litlle distorted relative to the planck one. This distortion is a trace of different nonequilibrium processes which took place during the period of the recombination.
Figs. 1, 2, and 3 present our calculations of the CMBR spectrum distortion due to deviation from the equilibrium during the recombination. The calculations are performed (in the frequency band from 0.5 GHz to 1000 GHz) in the frame of the standard cosmological model with Wtot=1, Wl~0.7 for different values of the densities of the nonrelativistic matter Wm and the baryonic matter Wb. Comparison of these results with observational data which will be obtained from future experiments may give independent estimations of the cosmological parameters Wm and Wb.
Fig.1. J is calculated nonequilibrium intensity. DJ is the difference between J and the equilibrium intensity with TR=2.725 K.
Fig.2. The relative distortion of the radiation temperature DT/T, as a frequency function. Lines correspond to h2Wb=0.016, 0.018, 0.020, at Wm.
Fig.3. The relative distortion of the radiation temperature DT/T, as a frequency function. Lines correspond to Wm=0.1, 0.3, 0.5, at h2Wb=0.018.