Abstract
We present the results of an intensive spectroscopic campaign in the optical waveband revealing that Cyg OB2 #8A is an O6+O5.5 binary system with a period of about 21.9 days. Cyg OB2 #8A is a bright X-ray source, as well as a non-thermal radio emitter. We discuss the binarity of this star in the framework of a campaign devoted to the study of non-thermal emitters, from the radio waveband to γ-rays. In this context, we attribute the non-thermal radio emission from this star to a population of relativistic electrons, accelerated by the shock of the wind-wind collision. These relativistic electrons could also be responsible for a putative γ-ray emission through inverse Compton scattering of photospheric UV photons, thus contributing to the yet unidentified EGRET source 3EG J2033+4118.
Based partly on data Obtained at the Observatoire de Haute-Provence, France.
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De Becker, M., Rauw, G., Swings, JP. (2005). On the Multiplicity of the O-Star Cyg OB2 #8A and its Contribution to the γ-Ray Source 3EG J2033+4118. In: Cheng, K., Romero, G. (eds) Multiwavelength Approach to Unidentified Gamma-Ray Sources. Springer, Dordrecht. https://doi.org/10.1007/1-4020-3881-X_29
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DOI: https://doi.org/10.1007/1-4020-3881-X_29
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