Search for gamma rays above 1014 eV from Cygnus X-3 during the June and July 1989 radio outbursts.

Abstract

We have looked for \ensuremath{\gamma}-ray emission above 100 TeV from the binary x-ray source Cygnus X-3 during a period of intense radio emission in the summer of 1989. We find no evidence for excess air showers from the direction of the source and the muon content of air showers from this direction is the same as that of ordinary cosmic rays. The flux of \ensuremath{\gamma} rays from Cygnus X-3 with energies exceeding 2.1\ifmmode\times\else\texttimes\fi{}${10}^{14}$ eV is 5.5\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}13}$ ${\mathrm{cm}}^{\mathrm{\ensuremath{-}}1}$ ${\mathrm{sec}}^{\mathrm{\ensuremath{-}}1}$ (90% C.L.).