Search for TeVγrays from SN 1987 A during December 1987 and January 1988

Abstract

Very-high-energy $\gamma$ rays emitted by the supernova 1987A were searched for at the Black Birch Range in New Zealand during December 1987 and January 1988. Data obtained in 42 hours of observation time give an upper bound on the flux at the 95% confidence level of 6.1 × ${10}^{-12\mathrm{}}$ ${\mathrm{cm}}^{-2\mathrm{}}$ ${\mathrm{s}}^{-1\mathrm{}}$ for $\gamma$ rays with energies above 3 TeV. Data obtained on 14 and 15 January are found to have excess counts, above the background level, corresponding to a flux of (1.9±0.5)×${10}^{-11\mathrm{}}$ ${\mathrm{cm}}^{-2\mathrm{}}$ ${\mathrm{s}}^{-1\mathrm{}}$ and a total energy of ∼${10}^{43}$ ergs.