EXOSAT Observations of the Cassiopeia A Supernova Remnant
Abstract
The young supernova remnant Cas A has been observed with the European X-ray observatory satellite Exosat. The remnant was observed with all instruments covering the range from 0.5 to 25 KeV. It is shown here that the emission from the remnant cannot be described by a two-temperature isothermal plasma in collisional ionization equilibrium. A simple Sedov (1959) blast-wave model assuming equilibration between the electron and ion temperature but nonionization equilibrium also does not result in an acceptable fit due to strongly enhanced emission at low energies (not above 2.5 KeV). Observations made with the Exostat imaging proportional counter show that this extra emission comes from the interior regions of the remnant. The source of this low-energy flux is most probably supernova ejecta heated in a reverse shock. No evidence is found for a high temperature (not less than 20 KeV) component.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- August 1988
- DOI:
- 10.1086/166612
- Bibcode:
- 1988ApJ...331..949J
- Keywords:
-
- Cassiopeia A;
- Exosat Satellite;
- Supernova Remnants;
- X Ray Sources;
- Abundance;
- Bremsstrahlung;
- Brightness Distribution;
- Crab Nebula;
- Heao 1;
- Line Spectra;
- Temperature Profiles;
- Astronomy;
- NEBULAE: INDIVIDUAL NAME: CASSIOPEIA A;
- NEBULAE: SUPERNOVA REMNANTS;
- RADIATION MECHANISMS;
- X-RAYS: SOURCES