Multiwavelength spectral models for SNR G347.3-0.5 from non-linear shock acceleration

The remnant G347.3-0.5 exhibits strong shell emission in the radio and X-ray bands, and has a purported detection in the TeV gamma-ray band by the CANGAROO-II telescope. The CANGAROO results were touted as evidence for the production of cosmic ray ions, a claim that has proven controversial due to constraining fluxes associated with a proximate unidentified EGRET source 3EG J1714-3857. HESS has now seen this source in the TeV band. The complex environment of the remnant renders modeling of its broadband spectrum sensitive to assumptions concerning the nature and parameters of the circumremnant medium. This paper explores a sampling of reasonable possibilities for multiwavelength spectral predictions from this source, using a non-linear model of diffusive particle acceleration at the shocked shell. The magnetic field strength, shell size and degree of particle cross-field diffusion act as variables to which the radio to X-ray to gamma-ray signal is sensitive. The modeling of the extant data constrains these variables, and the potential impact of the recent HESS detection on such parameters is addressed. Putative pion decay signals in hard gamma-rays resulting from hadronic interactions in dense molecular clouds are briefly discussed; the requisite suppression of the GeV component needed to accommodate the 3EG J1714-3857 EGRET data provides potential bounds on the diffusive distance from the shell to the proximate clouds.