QUENCHED RADIO-EMISSION IN CYGNUS-X-3

Flux density measurements for the x-ray binary Cygnus X-3 obtained at 15 GHz with the Ryle Telescope during 1994-1995 are compared with flux densities at 2.25 and 8.3 GHz obtained with the NRL-Green Bank Interf erometer. The Ryle Telescope measured lower quenched radio flux densit ies at 15 GHz than those reported at 2.25 and 8.3 GHz prior to the 199 4 February outburst. The time scales observed for the delay of small f lare peak flux densities at lower frequencies sets limits on opacity i n a spherically symmetric stellar wind. The upper-limit for the mass-l oss rate (M over dot similar to 1.0X10(-5) M./yr) is close to the dyna mical mass-loss rate for a 10 M. Wolf-Rayet star and 1.4 M. compact co mpanion. A higher mass-loss rate (M over dot 2.0X10(-5) M./yr) may occ ur either if the wind is very hot (3.5X10(5) K), or if it is cool (les s than or equal to 10,000 K) and partially ionized. Time scales observ ed for the onset of quenched radio emission support a model in which p article injection into the radio jet is suppressed. (C) 1996 American Astronomical Society.