SIMBAD references

We report the results of Rosat PSPC observations of the Supernova Remnant MSH 15-52. We present morphological and spectral properties of this object that complement and, in some instances, modify the results obtained by previous observations. The two main components of the remnant, the synchrotron nebula and the thermal nebula, are embedded in an extended, basically symmetric, region of X-ray emission. A new extended structure is found in the south-east part of MSH 15-52. The spectral analysis shows a discrepancy (by a factor ≃1.5) in the values of the hydrogen column density between the northern and southern components. Since the likelihood that the synchrotron nebula is coincidentally superposed on the other components is very remote, this disagreement may be related to peculiar physical properties of the emitting matter and of the surrounding medium. In particular, a contribution of a non-thermal component to the flux from the new extended symmetric nebula may be present.