Evolution of multi-frequency emission from Cygnus X-3 in the current giant flare
ATel #12701; S. A. Trushkin, N. A. Nizhelskij, P. G. Tsybulev, N. N. Bursov, A. V. Shevchenko (SAO RAS, Russia)
on 29 Apr 2019; 07:12 UT
Credential Certification: Sergei Trushkin (satr@sao.ru)
Subjects: Radio, X-ray, Gamma Ray, >GeV, VHE, Request for Observations, Binary, Black Hole, Transient
In ATel #12510 we have suggested that microquasar Cygnus X-3 will flare during some weeks after transition from a hard to a ultra-soft X-ray state. That happened after sixty days, when fluxes grew up higher 3 Jy at 15 GHz (AMI LA see http://www.mrao.cam.ac.uk/~dag/Cygnus-X3.html ) and up to 3.4 Jy at 37 GHz ( Metsahovi RO, see ATel #12668) on 18 April 2019. Indeed we have detected first signs of 10-fold flux increasing from 16 to 17 April (MJD 58589-590), observing with the RATAN-600 radio telescope at 4.7 GHz at least. The further measurements showed flux higher 1 Jy at all frequencies from 1.2 to 30 GHz with maximal flux about 7 Jy at 2.3 GHz on MJD 58596-597 and with following decay of the flare. The high-frequency spectra are optically thin with spectral indices from -0.6 to -0.3. But 29 April (MJD 58602.1) fluxes increased again in two-three times. The spectral index of the power law fitting is -0.58 at frequencies higher 2.3 GHz. Thus the flaring radio activity of Cygnus X-3 goes on, probably it is related with the gamma-ray flaring activity from Cygnus X-3 detected by AGILE (ATel # 12678). The further observations of Cygnus X-3 will be extremely useful.
The RATAN multi-frequency light curves of Cygnus X-3 in April 2019
