Radio emission of the Galactic X-rays binaries with relativistic jets

Abstract

Variable non-thermal radio emission from Galactic X-ray binaries is a trace of relativistic jets, created near accretion disks. The spectral characteristics of a lot of radio flares in the X-ray binaries with jets (RJXB) is discussed in this report. We carried out several long daily monitoring programs with the RATAN-600 radio telescope of the sources: SS433, Cyg X-3, LSI+61o303, GRS 1915+10 and some others. We also reviewed some data from the GBI monitoring program at two frequencies and hard X-ray BATSE (20-100 keV) and soft X-ray RTXE (2-12 keV) ASM data. We confirmed that flaring radio emission of Cyg X-3 correlated with hard and anti-correlated with soft X-ray emission during the strong flare (>$ Jy) in May 1997. During two orbital periods we investigated radio light curves of the remarkable X-binary LSI+61o303. Two flaring events near a phase 0.6 of the 26.5-day orbital period have been detected for first time at four frequencies simultaneously. Powerful flaring events of SS433 were detected at six frequencies in May 1996 and in May 1999. The decay of the flare is exactly fitted by an exponential law and the rate of the decay $\tau$ depends upon frequency as tau \propto \nu^{-0.4} in the first flare and does not depend upon frequency in the second flare, and is equal to \tau=6+-1 days at frequencies from 0.96 to 21.7 GHz in the last flare in May 1999. Many flaring RJXB show two, exponential and power, laws of flare decay. Moreover, these different laws could be present in one or several flares and commonly flare decays are faster at a higher frequency. The decay law seems to change because of geometric form of the conical hollow jets. The synchrotron and inverse Compton losses could explain general frequency dependences in flare evolution. In conclusion we summarized the general radio properties of RJXB.