EXOSAT Observations of the Supernova Remnant G109.1-1.0 and the X-Ray Pulsar 1E 2259+586

The authors report on the EXOSAT observation of the supernova remnant (SNR) G109.1-1.0+1E 2259+586 system. The spatial distribution of the X-ray emission as derived from the low-energy (<2 keV) data is very similar to that obtained from the Einstein Observatory. The various components of the source (SNR shell, pulsar, and jet) have different spectra. The jet is softer than the other components. The pulsar period was found to be 6.978725 s at the epoch of these observation, which implies a small positive Pwith respect to the value obtained from the Einstein data 4 years before. The data show no evidence for orbital motion. The central pulsating source is very peculiar in many respects and can hardly be interpreted in terms of a standard binary system.