Thermal and non-thermal radiation of rotating polarizable particle moving in an equilibrium background of electromagnetic radiation

A theory of thermal and nonthermal radiation in a vacuum background of arbitrary temperature generated by relativistic polarizable particle with spin is proposed. When the particle rotates, radiation is produced by vacuum fluctuations even in the case of zero temperature of the system. In the ultrarelativistic case, the spectral-angular intensity of radiation is concentrated along the velocity of the particle. At finite temperatures of particle and vacuum, the particle temperature (in its rest frame) rather quickly acquires an equilibrium magnitude depending on the velocities of rotation and uniform motion and the background temperature. This equilibrium temperature determines the intensity of radiation. The dynamical slowing down takes a very long time until the kinetic energy of uniform motion and rotation is converted into radiation.