Resonance Line Scattering in Supernova Remnant Shocks

We present a three-dimensional radiative transfer model to examine the effects of resonance-line scattering in the postshock flow behind a nonradiative supernova remnant shock. For a rippled shock front viewed edge-on, line scattering significantly reduces the observed flux of C IV lambda 1549 and N V lambda 1240, two important diagnostic lines in the ultraviolet spectra of supernova remnants. The correction factor (defined to be the ratio of the line flux that would be observed neglecting scattering to the actual observed line flux) is a function of position within the filament. For sufficiently large regions that include crisp edges as well as more diffuse regions of the filament structure, the C IV and N V correction factors are between about 1.5 and 3.5 (and the C IV correction factor is invariably larger than the N V correction factor). The correction factors have a larger range when smaller regions are considered. The C IV correction factor is about 6 at the filament edges, while the N V correction factor is about 4. These simulations of resonance-line scattering will be useful for the analysis of supernova remnant shock spectra.