CCD soft X-ray observations of the Puppis A supernova remnant

We present the first images and spectra of an astronomical object, other than the Sun, acquired with a CCD imaging X-ray spectrometer. During a 230 s sounding rocket observation, we have acquired moderate-resolution spectra and moderate-resolution images of a portion of the Pup A supernova remnant (SNR). Based on these data, we conclude that the X-ray spectrum of Pup A is inconsistent with any single-temperature equilibrium or nonequilibrium plasma model. We find evidence for variations in the emitting plasma on scales as small as 5′.0 and as large as 30′.0. The spatial structure of the spectral variations in the remnant is found to be inconsistent with the standard Sedov model for the evolution of a SRN into a homogeneous interstellar medium (ISM). We suggest that the remnant is expanding into a region of the ISM having a density of approximately 1 cm^-3 with inhomogeneities on the order of 50%. We have found evidence for the presence of a knot of plasma enriched in neon, but require more data to be conclusive.