SEARCH FOR TEV GAMMA-RAY EMISSION FROM BINARY RADIO PULSARS

Results of a TeV gamma-ray survey of six binary radio pulsars are pres ented. One of the objects, namely PSR B1855 +09, showed orbitally modu lated, pulsed emission with a probability due to chance of 1 x 10(-2) in the orbital phase range 0.15-0.25. The emission pattern is similar to the radio emission, although the double peak seems to show some str ucture. No confirmation of the reported DC emission at the L(4) positi on in the orbit from PSR B1957 +20 could be found, indicating an energ y cutoff at a few TeV. A model is proposed whereby orbitally modulated TeV gamma-ray emission could be produced in this system: Accelerated electrons from the pulsar wind will produce TeV gamma-rays through inv erse-Compton scattering in the curved shock surrounding the companion star. Doppler boosting along the shock front results in a maximum gamm a-ray energy of 6 TeV, and emission in a narrow angle in the general d irections of L(4) and L(5). The maximum predicted luminosity is slight ly less than measured by Brink et al. (1990).