Savchenko D. Distribution and observational manifestations of light dark matter

In the dissertation, the X-ray sky map based on the XMM-Newton observatory data is created. The method for fast discovery of the objects, suitable for exploring the 3.5 keV line — a possible candidate for the dark matter decay signal, is created. The method is applied to the obtained sky map. It is shown that the discrepancies between fluxes and significances of the 3.5 keV signal in papers by different groups could originate from the systematic uncertainty originating in the process of spectral modelling on the limited energy range. The search for the 3.5 keV line in the spectra of galaxy clusters with maximal expected dark matter decays flux. The line with the significance > 2σ is detected in 8 objects. It is shown that the behaviour of the line position rules out its instrumental origin while fluxes are in agreement with the dark matter decay signal expectations. From the analysis of the dwarf spheroidals' observed kinematics, the 2σ lower bound of m ≳ 190 еВ on the dark matter particle mass is obtained. The estimators for the quadruple scale-invariant statistical cosmic microwave background anisotropy are built. The obtained estimators do not depend on the cosmological model parameters.