ИСТИНА

New UBV-photoelectric observations of the well-known X-ray binary system Cyg X-1/V1357 Cyg near primary minimum were obtained. The detailed analysis of these observations confirms the existance of an additional blue radiation that appeara as a narrow peak with amplitude 0.01-0.02 near phase 0.00 on the light curve )the superior conhunction of the relativistic component) first detected by Luyty (1985). The appearence of this narrow peak of the additional blue radiation on the light curve of Cyg X-1 can be explained as the radiatioj of relativistic electrons in the disturbed magnetic field of the optical star in the frames of the model proposed by Ikhsanov and Fabrika.