X-RAY-EMISSION FROM SUPERNOVA-REMNANTS OBSERVED WITH ROSAT

Spectrally resolved X-ray images of galactic supernova remnants have been obtained both from the ROSAT all-sky survey and a number of pointed observations. There is substantial evidence for significant spatial variation in temperature, density and pressure across the older, thermal remnants like the Vela SNR, the Cygnus Loop and the. North Polar Spur. Both the brightness distribution and the pressure variations observed point towards recently shocked interstellar clouds and filaments, which dominate the X-ray emission pattern. Across the Puppis-A SNR an are-shaped absorption structure has been detected, which is demonstrated to be. produced by cold gas located close to the shock front of the Vela SNR. Across' IC443 a similar absorption pattern has been observed, which is created by a cold shell associated. with a previously unknown, ROSAT discovered SNR, which lies in front of IC443. Finally, a statistically overview of the SNRs detected in the ROSAT all-sky survey is presented. About half of the catalogued radio remnants have. been observed in the survey and another 90 sources have. been found which are considered to be candidates of new SNRs.