摘要
Recently two especially important properties of ultra-high-energy （UHE） γ-rays(Eγ>1015 eV) from the Cosmos have been discovered: （i） these γ-rayscorrespond to more than ten high-energy celestial bodies （Nature, 315（1985）, 205）, of which seven （Cyg X-3, Vala X-1, Cir X-1, Sco X-3, Cen X-3, GX 301-2 and GX 304-1） are in the Milky Way galaxy, four in the Large Megellanic Cloud and one in the Small Megellanic Cloud,
