X-rays from mass-loaded supernova remnants in the large magellanic cloud

Observations of H II complexes surrounding OB associations in the Large Magellanic Cloud have revealed X-ray luminosities that cannot be explained by stellar winds alone or by supernova remnants (SNRs) evolving inside stellar-wind bubbles. In neither case would there be enough matter inside the bubbles to produce the observed flux. We propose a model in which a SNR evolves inside an extremely diffuse stellar-wind bubble (formed by the OB association stars) but the density in the SNR is augmented through hydrodynamic ablation of cool, dense clumps by the post-blast wave SNR flow. We present hydrodynamic calculations, including a nonequilibrium treatment of the ionization and cooling, of the evolution of such mass-loaded SNRs. We show that the models naturally explain many of the properties of the observed diffuse X-rays. In particular, we find dose quantitative agreement between one of our models and observed parameters of N51D.