X-ray studies of supernova remnants

For thousands of years after the explosion of a massive star, the effects of this event on the surrounding medium can still be seen in the form of a supernova remnant (SNR). Across the electromagnetic spectrum we see evidence of both the shock wave of the initial explosion propagating out into the interstellar medium (ISM), and the hot shrapnel of stellar ejecta that had been processed into higher Z elements in the very explosion itself. Over the course of my dissertation, I have conducted a variety of X-ray studies of SNRs, involving both the composition of the ejecta and the physics of the outer blast wave. My studies of ejecta have ranged from examining the global composition of young SNRs to characterizing individual knots of ejecta. In one case, the ejecta-dominated nature of the overall X-ray spectra of two galactic SNRs allowed us to identify them as young. In another case, we were able to pinpoint where in the star individual knots of ejecta originated by tracing the type of explosive nucleosynthesis that produced them. My studies of the outer blast wave have investigated the distribution of energy in collisionless shocks. In one we addressed the partition between thermal and relativistic populations, and in another we compared the energies of the thermal populations of electrons and protons as a function of shock speed.