We present the results of a joint spectral analysis of RXTE PCA , ASCA SIS , and ROSAT PSPC data of the supernova remnant SN 1006 .
This work represents the first attempt to model both the thermal and nonthermal X-ray emission over the entire X-ray energy band .
The thermal flux is described by a nonequilibrium ionization model with an electron temperature kT _ { e } = 0.6 keV , an ionization timescale n _ { 0 } t = 9 \times 10 ^ { 9 } cm ^ { -3 } s , and a relative elemental abundance of silicon that is 10–18 times larger than the solar abundance .
The nonthermal X-ray spectrum is described by a broken power law model with low- and high-energy photon indices \Gamma _ { 1 } = 2.1 and \Gamma _ { 2 } = 3.0 , respectively .
Since the nonthermal X-ray spectrum steepens with increasing energy , the results of the present analysis corroborate previous claims that the nonthermal X-ray emission is produced by synchrotron radiation .
We argue that the magnetic field strength is significantly larger than previous estimates of about 10 \mu G and arbitrarily use a value of 40 \mu G to estimate the parameters of the cosmic-ray electron , proton , and helium spectra of the remnant .
The results for the ratio of the number densities of protons and electrons ( R = 160 at 1 GeV ) , the total energy in cosmic rays ( E _ { cr } = 1 \times 10 ^ { 50 } ergs ) , and the spectral index of the electrons at 1 GeV ( \Gamma _ { e } = 2.14 \pm 0.12 ) are consistent with the hypothesis that Galactic cosmic rays are accelerated predominantly in the shocks of supernova remnants .
Yet , the remnant may or may not accelerate nuclei to energies as high as the energy of the “ knee , ” depending on the reason why the maximum energy of the electrons is only 10 TeV .