Dmitry Khangulyan (JAXA)
Gamma-Ray Emitting Binary Systems
Pulsars and pulsar wind nebulae (PWN) represent the most numerous class of galactic gamma-ray emitting sources. However, only one pulsar (with a few candidates) located in binary systems is confirmed as gamma-ray emitters. Typical binary pulsars accrete material from companion stars, and the gravitation energy is released through bright X-ray emission. However, the accretion process significantly affects the pulsar magnetosphere, and in particular this ceases the pulsar wind, which is essential for formation of PWN. Therefore, to be a gamma-ray emitter binary system should contain a pulsar powerful enough to prevent the accretion. In this case a compactified nebula can be formed in binary systems. However, this type of sources features several important differences as compared to their isolated siblings. Several factors, e.g., environmental impact and hydrodynamic interaction regime, have crucial influence on the processes occurring in gamma-ray binary systems. I will review in detail the physical scenario for binary pulsars and will discuss the implication of different observational data, obtained with both ground based and space gamma-ray detectors.