A NewASCAandROSATStudy of the Supernova Remnant G272.2−3.2

G272.2-3.2 is a supernova remnant (SNR) characterized by an apparentcentrally brightened X-ray morphology and thermally dominated X-ray emission.Because of this combination of Sedov-type (thermal emission) and non-Sedov type(non-shell like morphology) features, the remnant is classified as a ``thermalcomposite'' SNR. This class of remnant is still poorly understood due in partto the difficulties in modeling accurately all the physical conditions whichshape the emission morphology. In this paper we present a combined analysis ofdata from the ASCA and ROSAT satellites coupled with previous results at otherwavelengths. We find that the X-ray emission from G272.2-3.2 is best describedby a non-equilibrium ionization (NEI) model with a temperature around 0.70 keV,an ionization timescale of 3200 cm^-3 yr and a relatively high column density(NH about 10^22 atoms/cm^2). We look into the possible explanations for theapparent morphology of G272.2-3.2 using several models (among which both cloudevaporation and thermal conduction models). For each of the models consideredwe examine all the implications on the evolution of G272.2-3.2.Comment: 26 pages, 8 figures. Accepted for publication in Ap