SEARCHES FOR ULTRA-HIGH-ENERGY GAMMA-RAYS FROM SN 1987A AND CENTAURUSX-3

Searches for gamma rays above 100 TeV from SN 1987A and above 50 TeV f rom Cen X-3 were carried out with an air shower array at Mount Chacalt aya over a period of 3 years. The array, which consists of 13 4 m(2) a nd 28 1 m(2) scintillation detectors, was located on a slope of about 30 degrees facing southward to effectively observe air showers coming from the directions of these sources. In the analysis, a selection by shower age parameter was applied to reduce the background due to showe rs initiated by protons or nuclei. No significant excess of gamma rays (and/or neutral particles) from these sources was found; our upper li mits on the flux of gamma rays above 100 TeV from SN 1987A and above 5 0 TeV from Cen X-3 are 2.2 x 10(-13) and 3.5 x 10(-13) photons cm(-2) s(-1) (95% confidence level), respectively.