Schematic representation of the bow shock nebula around binary system containing the millisecond pulsar B1957+20. The bow shock is created due to the motion of the binary system through the interstellar space with the velocity of  ~220 km   s^-1. Relativistic electrons with the Lorentz factors γ_e are accelerated by the pulsar itself or by the shocks due to the pulsar wind interactions. The electrons are collimated by the bow shock in the direction opposite to the motion of the binary system. These electrons comptonize the microwave background radiation (MBR) and the infrared radiation (INF) from the galactic disk. As a result γ-ray photons are produced (tagged as E_γ) at the region behind the pulsar.