DYNAMICS OF PRIMORDIAL HYDROGEN RECOMBINATION WITH ALLOWANCE FOR A RECOIL FOR SCATTERING IN THE Ly-α LINE

It is shown that taking into account a recoil for radiation scattering in the Lyα line can lead to a noticable acceleration of primordial hydrogen recombination. Thus for ΛCDM model a decrease of ionization degree exceeds 1% for redshifts z in a range 800 – 1050 achieving ≈ 1.3% at z = 900. Corresponding corrections to the cosmic microwave background power spectra can achieve 1.1% for TT spectra and 1.7% for EE ones. Radiative transfer in these calculations was treated in a quasistationary approximation. Numerical solutions are also obtained in diffusion approximation for a nonstationary problem of Ly-α line radiative transfer under partial frequency redistribution with a recoil. An evolution of a local line profile is traced to as well as an evolution of a relative number of uncompensated transitions from 2p state down to 1s one. It is shown that taking into account nonstationarity of Ly-α line radiative transfer can lead to an additional acceleration of primordial hydrogen recombination.