Rudakovskyi A. Structure formation and reionization of the Universe in dark matter models.

The reionization process is studied in warm dark matter models. It was shown that the reionization is much faster in 7 keV sterile neutrino dark matter, which could explain the observed 3.5 keV radiation line, than in the cold dark matter scenario. It is obtained that the model-independent results of observations on the reionization epoch are described slightly better in the model of 7 keV sterile neutrinos than in the model of cold dark matter. It is shown that particles of warm dark matter with a mass m≳2 keV can not be reliably excluded by the position (frequency) of the 21-cm absorption signal suggested by EDGES due to uncertainties in the star formation efficiency in the first galaxies. A new semi-analytical method for calculating the density distribution in the halo of fermionic dark matter is proposed.