X-Ray Studies of the Supernova Remnant N132D. I. Morphology

From studies of the X-ray image of the supernova remnant N132 D in the Large Magellanic Cloud, the author determines that the supernova explosion occurred within a cavity in the interstellar medium. As a possible explanation for the formation of such a cavity he considers the H II region of the precursor star, which gives an adequate fit if the precursor stellar type is later than B0. The author also derives limits on the age and explosion energy, assuming the applicability of the Sedov solution. Consistency with the dynamical age estimates from the high-velocity oxygen-rich optical filaments can be obtained with a cavity density of ≡0.01 cm^-3 or less and an explosion energy of ≡10⁵¹ergs.