X-ray observations of the supernova remnant N103B in the large Magellanic cloud

Abstract

We present X-ray observations of the supernova remnant N103B made with both the low-energy and medium-energy experiments on board EXOSAT. Fitting the spectral data obtained from EXOSAT and from the Einstein Observatory with thermal models yields satisfactory fits for a temperature of ~1.2kev, while power-law models appear to be excluded. The X-ray luminosity of N103B IS 1.6 × 10³⁷ ERGS S^-1 in the 0.05-4.5kev energy band. The X-ray emission as seen in the low-energy telescope on EXOSAT is centrally peaked. The upper limit on its extent in soft X-rays derived from this experiment is ~25″ which is comparable to its optical size. The spatial resolution of the present observations is not sufficient to discern the morphology of X-ray emission from N103B. Its smallest diameter and high luminosity suggest that it is quite young( 600-1200yr). The failure of power-law models to explain the spectral data on N103B suggests that, dispite its centrally peaked surface brightness distribution, its resemblance to a crab-like supernova remnant is only superficial. A central source with ''Crab-like'' nonthermal X-ray luminosity of up to 6 × 10³⁵ ergs s^-1 is, however, allowed by the spectral data.