X rays from radio binaries

Abstract

THE properties of the radio binary systems, CC Cas, AR Lac, β Per (Algol), β Lyr, b Per and Cyg X-l have been listed¹. A thermal interpretation of the radiation from Algol² requires a much larger X-ray flux than the observed value of 3.8 × 10 ⁻¹¹ erg cm⁻² s⁻¹ keV⁻¹ in the 2–6-keV energy range³. The observation of some non-thermal flares, and the small size of the radio source in Algol indicate the non-thermal nature of the radio emission¹. We interpret the radio emission as synchrotron radiation and suggest that the observed X-ray emission is inverse Compton scattering of the light of the primary star by the radio electrons. We calculate X-ray emission from other radio binaries using this model. The energy for the radio electrons can arise from annihilation of magnetic lines connecting the binary stars twisted by the rotation of the stars⁴.