Ultra-high energy gamma-ray astronomy using an EAS array : search foremission from 100 MeV sources.

Attention is given to extensive air shower detection techniques that are currently being used for gamma-ray astronomy above 10 to the 15th eV. Ultrahigh energy gamma-rays have been detected from Cygnus X-3 and Vela X-1, and a search for such emissions from other binary X-ray sources is in progress. The most important consequence of recent observations is that neutron star binary X-ray sources are probably responsible for at least some of the cosmic rays above 10 to the 15th eV, especially if the gamma-ray emission is due to interactions of protons or nuclei which have been accelerated by the object.