Very high energy gamma-quanta 1–65 TeV from the Cygnus X-3 binary

The results of almost ten-year observation of Cygnus X-3 point source by SHALON mirror Cherenkov telescope are presented. The galactic source Cygnus X-3, known for more than 10 years as a source with variable intensity 10 −11 − 5 • 10 −12 c m −2 s −1 , was regularly observed since 1995 with average gamma-quantum flux F ( E O > 0.8 T e V ) = ( 6.8 ± 0.7 ) • 10 −13 c m −2 s −1 . The flux in 2003 was ( 1.79 ± 0.33 ) • 10 −12 c m −2 s −1 . Earlier, in 1997, an increase in the flux was also observed ( 1.2 ± 0.5 ) • 10 −12 c m −2 s −1 . The limits on gamma-rays from Cygnus X-3, the source that results stimulated the construction of many new detectors are presented. These upper limits and SHALON fluxes are now more than a factor 100 less than the fluxes originally reported.