FORBIDDEN IRON LINES AND DUST DESTRUCTION IN SUPERNOVA REMNANT SHOCKS: THE CASE OF N49 IN THE LARGE MAGELLANIC CLOUD

Abstract

We present the results of a complete integral-field survey of the bright supernova remnant (SNR) N49 in the Large Magellanic Cloud, obtained with the WiFeS instrument mounted on the ANU 2.3 m telescope at Siding Spring Observatory. From theoretical shock modeling with the new MAPPINGS 5.1 code, we have, for the first time, subjected the optical Fe emission line spectrum of an SNR to a detailed abundance and dynamical analysis covering eight separate stages of ionization. This allows us to derive the dust depletion factors as a function of ionization stage. We have shown that there is substantial (30%–90%) destruction of Fe-bearing dust grains in these fast shocks ( v s ∼ 250 km s −1 ), and we have confirmed that the dominant dust destruction occurs through the non-thermal sputtering and grain–grain collision mechanisms developed in a number of theoretical works.