Study of Cygnus X-3 at ultrahigh energies during the 1989 radio outbursts

A unique feature of Cygnus X-3 is that, occasionally, it has large radio outbursts that begin very abruptly and last for several days. Several experiments in the past have claimed to observe signals above 1 TeV correlated with these radio bursts; the most recent bursts occurred in June and July 1989. No significant signal was observed by the CYGNUS experiment over time scales longer than a day during this time; a 90-percent confidence-level limit of 3.0 x 10 to the -13th/sq cm per sec is placed on the flux above 50 TeV during the period from May 15 to July 31, 1989. (Author)