ИСТИНА

We correctly estimate an effect of the thermal Comptonization when the cosmic microwave background photons propagate through optically thin hot clouds. Up to now a solution of the Kompaneets equation was applied to describe distortions of CMB spectrum induced by plasma in galaxy clusters. In our work we consider the radiative transfer (Comptonization) problem of photon propagation through the cloud of finite size. Its solution describes the nature of observed CMB distortions more accurately. Our solution gives a form of the CMB distortion which is significantly different from the form used in the literature following the Zeldovich & Sunyaev approach. This deviation dominates the relativistic and kinetic corrections. Moreover, a physically motivated analytic relation between the solution parameter and the physical characteristics of the Comptonizing cloud allows us to disentangle the electron temperature and optical depth of the cloud. We can estimate these parameters using existing observations.