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Cygnus X-3 is in flare: observation by RATAN and GMRT

ATel #1881; Sergei Trushkin (SAO RAS), Sabyasachi Pal (NCRA-TIFR), Sushanta Mondal (ICSP), N. N. Bursov (SAO RAS), C. H. Ishwara-Chandra (NCRA-TIFR)
on 24 Dec 2008; 19:14 UT
Credential Certification: Sabyasachi Pal (spal@ncra.tifr.res.in)

Subjects: Radio, X-ray, Request for Observations, Binary, Black Hole

Referred to by ATel #: 9444

Galactic micro-quasar Cygnus X-3 is currently undergoing a flaring activity. From our observation by RATAN, we detect 6.6, 4.0, 3.3, 2.6, 2.4 and 2.1 Jy flux density in 2.15, 4.8, 7.7, 11.2, 21.7 and 30 GHz respectively on MJD 54819.495 (19.495 Dec 2008 UT). By the follow up GMRT observation on 54820.039 (20.039 Dec 2008 UT), we found that the peak of the flare is shifting towards lower frequency ( < 1 GHz) region and the preliminary analysis shows ~1.9 and ~6.9 Jy flux density in 244 and 614 MHz respectively while the fluxes in higher frequency, observed by RATAN in the same day, started decreasing and measured to be 4.9, 2.9, 2.4, 1.8, 1.4, 1.4 Jy in 2.15, 4.8, 7.7, 11.2, 21.7 and 30 GHz respectively. A plot of recent flux densities is available at http://www.ncra.tifr.res.in/~spal/cygx3_dec08/c3_lc_2008dec.png . Daily hard X-ray monitoring by BAT on board Swift, which can be found in http://swift.gsfc.nasa.gov/docs/swift/results/transients/CygX-3/ , also shows that the source is undergoing a flaring activity with 0.028 and 0.042 count/cm^2/s rate on MJD 54817 and 54822 respectively in 15-50 keV. There is no BAT observation when the source was on the top of the flare.

More observations by GMRT and RATAN is planed. Multi-frequency monitoring of the source is encouraged.