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A radio flare of a microquasar Cyg X-3

ATel #1838; Kenta Fujisawa (Yamaguchi University), Masato Tsuboi (ISAS/JAXA), Sergei Trushkin (SAO RAS), Taro Kotani (Aoyama Gakuin University)
on 11 Nov 2008; 14:23 UT
Credential Certification: Sergei Trushkin (satr@sao.ru)

Subjects: Request for Observations, Binary, Black Hole, Transient

We report that at 06:30UT on 11 Nov 2008 (MJD54781.27) a microquasar Cyg X-3 (RA=20:32:25.78, Dec=40:57:27.9 J2000) is showing a flare, and its radio flux density of about 1.0 +- 0.2 Jy at 8.4 GHz. This measurement has been made with Yamaguchi-32m radio telescope. Pooley (Atel #1828) report that Cyg X-3 was in a quenched state (2 to 3 mJy at 15 GHz) on 2008 November 4 & 5. As Pooley noted that such low flux densities are often followed by a major flare. Before the RATAN-600 radio telescope measured fluxes were 20 mJy and 50 mJy at 4.8 GHz, 20 mJy and 80 mJy at 7.7 GHz, and 35 mJy and 95 mJy at 21.7 GHz respectively on 08 Nov 2008 (MJD54778.6) and 10 Nov 2008 (MJD54780.60). We have just started monitoring observations of Cyg X-3 with Yamaguchi-32m radio telescope on 11 Nov 2008 and found the flare.