The non-thermal X-ray emission of SN 1006 and the implications for cosmic rays

We present time results of a spectral analysis of RXTE, ASCA, and ROSAT data of SN 1006. These data were fit with several sets of thermal and non-thermal X-ray emission models to characterize time global spectral properties of the remnant. The present work represents the first attempt to model both the thermal and non-thermal X-ray emission over the entire X-ray energy band from 0.12-17 keV. The non-thermal X-ray spectrum is described by a broken power-law with low- and high-energy photon indices of 2.1 and 3.0, respectively. Since this spectrum steepens with increasing energy, our results support the claims that the emission is produced by synchrotron radiation from 100 TeV electrons. Using the radio and X-ray data, we estimate the parameters of the cosmic-ray electron, proton, and helium spectra. The results suggest that the ratio of the number densities of protons and electrons is 150 at 1 GeV and that the total energy in cosmic rays is 10(50) erg. These results and the spectral index of the electrons at 1 GeV (Gamma (e) = 2.14 +/- 0.12) are consistent with the hypothesis that Galactic cosmic rays are predominantly accelerated in the shocks of supernova remnants. However, SN 1006 may or may not accelerate cosmic-ray protons to energies approaching the "knee" in the cosmic-ray spectrum.