Expected gamma-ray emission from x-ray binaries
  It is at present well known that conditions at some massive binary systems allow acceleration of particles and production of the GeV-TeV gamma-rays. However, which particles are responsible for this emission and what radiation processes are engaged is at present not completely clear. We discuss what parameters can determine the acceleration process of particles and high energy radiation produced by them within massive binary systems. 
W. Bednarek
astro-ph.HE