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%-confidence-level limit of 3.0{times}10{sup {minus}13} cm{sup {minus}2} s{sup {minus}1} is placed on the flux above 50 TeV during the period from 15 May to 31 July 1989.