On the origin of high-velocity gas H alpha-emission from the Cygnus Loop and IC 443
Abstract
Summary. Wide wings of Ha lines in spectra of both SNR's are explained by the collisional excitation of neutral hydrogen passing through the external shock. Despite the high (some millions of degrees) temperature of the external shock, hydrogen emits before ionization a Ha-flux which can be comparable with the observed one. The high-velocity gas should not be observed in nebulae surrounded by H I1 regions, like Cas A, Crab, Vela X, Pup X; but it may be seen in Tycho and Kepler. Key words: supernova remnants - shock waves in interstellar matter
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- December 1979
- Bibcode:
- 1979A&A....80..167B
- Keywords:
-
- H Alpha Line;
- Hydrogen Clouds;
- Interstellar Matter;
- Nebulae;
- Shock Wave Propagation;
- Supernova Remnants;
- Electron Energy;
- Gas Flow;
- Molecular Excitation;
- Astrophysics