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A year of unprecedented flaring activity of the microquasar Cyg X-3

ATEL # 984; S.A.Trushkin, N.N. Bursov, N.A. Nizhelskij (SAO RAS)
on 30 Jan 2007; 19:34 UT
Password Certification: Sergei Trushkin (

Subjects: Radio, X-ray, Request for Observations, Binaries, Black Holes

We report that on 30 Jan 2007 (MJD54130.38) radio fluxes from the microquasar Cyg X-3 (RA=20:32:25.78, Dec=40:57:27.9 J2000) reached 9.35, 11.9, 9.4, 7.0 and 6.2 Jy, at 1.0, 2.3, 4.8, 7.7 and 11.2 GHz respectively, increasingly growing from 6 mJy (4.8 GHz) during last 20 days. We have carried out a daily monitoring program of microquasars with the RATAN-600 radio telescope and have detected a lot of bright flares higher 1 Jy from Cyg X-3 in 2006 (Trushkin et al., astro-ph/0611550). After almost four years of quiet state (2002-2005) when there are no bright radio flares, the low soft X-ray (2-12 keV, RXTE) state have been changed to high one on 15 Jan 2006, meanwhile the hard X-ray flux (15-50 keV, Swift/BAT) dropped down to almost zero level, and then appeared only before or during powerful radio flares (see also: ATEL #952, #828, #809, #807, #806, #727). The RATAN spectrum on Jan 30.38 (UT) is well fitted by a power-law with spectral index -0.41 from 2.3 to 11.2 GHz. The recent RATAN-600 simultaneous spectra (1-30 GHz) and light curves are available at:
The RATAN-600 monitoring of Cyg X-3 will continue to 1 March.

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