SUZAKU VIEW OF POWERFUL GAMMA-RAY QUASARS

摘要

We present the results from multiwavelength campaigns of three powerful gamma-ray quasars, PKS 1510-089, RBS 315 and Swift J0746.3+2548, recently organized with Suzaku. The Suzaku observation provided one of the highest S/N X-ray spectra ever reported between 0.3 and 50 keV. For these quasars, the X-ray spectrum is well represented by an extremely hard power-law with photon index Gamma similar or equal to 1.2, but is augmented by an additional soft component apparently below 1 keV for PKS 1510-089, whereas a strong deficit of soft photons is observed in RBS 315. We model the broadband spectra of these powerful quasars and argue that the power of the jet is dominated by protons but with the number of electrons/positrons exceeding the number of protons by a factor similar or equal to 10. We also argue that an extremely hard X-ray spectra may result from a double power-law form of the injected electrons, with the break energy gamma br similar or equal to 1000 corresponding to the anticipated threshold of diffusive shock acceleration.