Broadband SED and Radio/X-ray Correlation of Accreting Stellar Black Hole Systems

Broadband spectral energy distribution (SED) is crucial to studying the radiation mechanism of accreting stellar black hole systems. Here we report results from a systematic study of the SED of two systems, XTE J1550-564 and H 1743-322, in outburst. The jets of both sources have been directly imaged at both radio and X-ray frequencies, which makes it possible to constrain the spectrum of the radiating electrons in the jets. Based on the modeling of the observed SEDs of the jet "blobs" with synchrotron emission, we applied the synchrotron model to the radio spectrum of the total emission and extrapolated the results to higher frequencies. We found that while the synchrotron radiation from the jets can account for nearly 100% of the measured radio fluxes, it contributes little to the observed X-ray emission, when the source is relatively bright. In this case, the X-ray emission is most likely dominated by emission from the accretion flows. We also examined the correlation between the observed radio and X-ray luminosities. The implication of the results is discussed.