Broadband Observations and Modeling of the Shell‐Type Supernova Remnant G347.3−0.5

The supernova remnant G347.3--0.5 emits a featureless power-law in X-rays,thought to indicate shock-acceleration of electrons to high energies. We hereproduce a broad-band spectrum of the bright NW limb of this source by combiningradio observations from the Australia Telescope Compact Array (ATCA), X-rayobservations from the Advanced Satellite for Cosmology and Astrophysics (ASCA),and TeV gamma-ray observations from the CANGAROO imaging Cerenkov telescope. Weassume this emission is produced by an electron population generated bydiffusive shock acceleration at the remnant forward shock. The nonlinearaspects of the particle acceleration force a connection between the widelydifferent wavelength bands and between the electrons and the unseen ions,presumably accelerated simultaneously with the electrons. This allows us toinfer the relativistic proton spectrum and estimate ambient parameters such asthe supernova explosion energy, magnetic field, matter density in the emissionregion, and efficiency of the shock acceleration process. We find convincingevidence that the shock acceleration is efficient, placing >25% of the shockkinetic energy flux into relativistic ions. Despite this high efficiency, themaximum electron and proton energies, while depending somewhat on assumptionsfor the compression of the magnetic field in the shock, are well below theobserved `knee' at about 10^{15} eV in the Galactic cosmic-ray spectrum.Comment: Submitted to ApJ, 22 pages, 5 figure