Extended soft X-ray emission from the Crab nebula.

The grazing-incidence X-ray telescopes on the Copernicus satellite were used to scan the Crab Nebula with an angular resolution of approximately 2 arcmin. Using a more precise technique for removing the non-X-ray background, the 0.5-1.5-keV data from this scan are processed with the ART algorithm. A significant extension to the northeast of the nebula is found which is also evident in the raw data. A more diffuse emission region is also apparent to the south of the nebula. These features may be associated with the residual soft X-ray flux observed during a lunar occultation of the Crab Nebula. The present data are consistent with the extensions having a spectrum which is softer than that of the main X-ray source in the Crab Nebula.