X rays from supernova remnants.

Analysis of X-ray emission from supernova remnants is aided by grazing-incidence X-ray cameras borne by satellites and by utilizing lunar occultation. The analysis provides new data on supernova ejecta and the structure of the surrounding interstellar medium as the shocked material ejected by the exploded supernova interacts with dust-gas clouds. The presence in the Crab Nebula of a pulsar responsible for enormous energy emission at visible, radio, and X-ray wavelengths is confirmed, but the X-ray emission mechanism at work in Cassiopeia A and in Tycho's nova appears to be complex interaction between high-velocity magnetohydrodynamic shock waves and interstellar material swept up by the shocks.