Formation of the 255 keV annihilation line near the magnetic poles of pulsars

The possibility of existance is discussed for pulsars emitting soft γ radiation near their magnetic poles upon the annihilation of ultrarelativistic positrons from the magnetosphere and electrons from the surface of a star. With an increase in the energy of incident positrons, the photon energy of this backward radiation tends to a constant value m _e c ²/2=255 keV. This radiation is shown to be directed opposite to the positron flux direction.