Interaction of Supernova Remnants with the Interstellar Medium.
Abstract
We investigate the way in which the shock-wave produced in the interstellar medium by a supernova explosion slows. The shock path and the motion of the gas behind the shock are computed numerically using von Neumann and Richtmyer's method of artificial viscosity. We take into account the effects of radiative cooling behind the shock front. The cooling has an important effect on the motion for old remnants and leads to thermal instabilities in obj ects as old as the Cygnus Loop. We conclude that the visible filaments in the Loop are regions of thermal instability where the density rises and the temperature falls by large factors from their values immediately behind the shock front in a distance of the order of 0.01 PC. A shell of cool gas having a density about 102 times that in the undisturbed interstellar medium must lie behind the filaments in the Cygnus Loop. The mass in this shell should be greater than 100 M0 and is perhaps as great as 1000 M0. We also investigate the motion taking into account the interstellar magnetic field. In this case, as has been shown by van der Laan, the compression of the magnetic field limits the density rise in the thermal instability behind the shod~.
- Publication:
-
The Astronomical Journal
- Pub Date:
- February 1966
- DOI:
- 10.1086/110009
- Bibcode:
- 1966AJ.....71Q.162G