Cherenkov Telescope results on gamma-ray binaries

Abstract

In the past ten years of regular operations, a new generation of Cherenkov telescopes have established binary systems as a new class of Very High Energy gamma-ray (VHE) emitters. Particle acceleration in these systems may occur either in an accretion-powered jet (microquasar) or in the shock between a pulsar wind and a stellar wind (wind-wind). This paper describes the phenomenology of the three VHE binaries PSR~B1259-63, LS 5039 and LS I +61 303. Two other objects may belong to this new class: HESS J0632+057 is a point-like variable VHE source whose multiwavelength behaviour resembles that of the other binaries, whereas Cyg X-1 is a well-known accreting system which may have been detected in VHE during a flaring episode. The paper concludes with a review of the latest searches for other binaries with Cherenkov telescopes, with special emphasis on Cyg X-3.