Abstract
The inhomogeneous interstellar medium determines the evolution and appearance of the Cygnus Loop supernova remnant. Specifically, interactions of the shock front with large interstellar clouds produce nearly all of this remnant's emission at X-ray and optical wavelengths. Observations with the Chandra X-ray Observatory and the Hubble Space Telescope reveal the dynamic blast wave and the detailed structure of individual clouds. In some cases, notably the western limb, a simple one-dimensional model of the interaction is sufficient, whereas other regions require discrimination of multiple projections or more complex models. The Cygnus Loop ultimately serves as a useful probe of the interstellar medium and as one of the best existing laboratories of shock physics.
