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Session 45 - New Insights on X-ray Binaries.
Display session, Wednesday, June 11
South Main Hall,

[45.04] The Early 1997 Outburst of Cygnus X-3

F. D. Ghigo (NRAO), E. B. Waltman (NRL), G. G. Pooley (MRAO/Cambridge), M. L. McCollough (NASA/MSFC), R. M. Hjellming (NRAO)

The well-known X-ray binary system Cygnus X-3 underwent major radio flaring activity in early 1997. Data are presented from the Green Bank Interferometer at 8.3 and 2.25 GHz and from the Ryle Telescope at 15 GHz. Comparison is made with hard X-ray (HXR: 20-100 keV) observations from BATSE. The main outburst reached about 10 Jy at all three radio frequencies on February 4th. This flare occurred during an extended period of activity which included several small flares. However, unlike the major outbursts of 1972 and 1991, the February 1997 flare decayed quickly, and the post flare activity was relatively minor. Quenched radio emission (<=0.03 Jy) was seen for a few days prior to the main flare. Comparison with BATSE HXR data showed a positive correlation between the HXR and radio during the major flares, but an anti-correlation during the several months of quiescent behavior prior to the flaring episode. This provides more evidence for the correlations discovered by McCollough, Harmon, et al (in press) and suggests that different models may link HXR and radio emission in quiescent versus flaring episodes. This and other implications of these results for models of this object will be discussed.

Program listing for Wednesday