High-energy observations of black hole binaries with the INTEGRAL
  satellite
  Black-hole binaries are important sources through which studying accretion
onto compact objects. In the X/gamma-ray domain, these objects show several and
complex spectral behaviours and transitions. Based on INTEGRAL observations
collected during the last eightyears, we have now a new view on the high energy
emission of black-hole binary. An additional component above 200 keV has been
observed in a few systems, during either hard/intermediate or low/hard states.
The nature of this hard-tail is still debated, as also the one observed in soft
states. However, among a number of models, it is usually attributed to the
presence of a small fraction of non-thermal electrons in a hot-Comptonising
plasma. I review the high energy emission from black hole binary systems and
report on some INTEGRAL observations of three different objects: 1E
1740.7-2942, GX 339-4, Cyg X-1.
