We present all OSSE observations to date of the Cas A supernova remnant. The objectives are to detect the ^44^Ti lines, one of which has been reportedly detected by COMPTEL, and the hard X-ray continuum above 40keV, as indicated by HEAO-A2 measurements. Our best fit flux in each of three ^44^Ti lines is (+1.76 +/-^1.51^_1.48_)x10^-5gamma/cm^2^/s with χ^2^nu_=1.01, d.o.f.=1780. The implied ^44^Ti mass of ~10^-4^Msun_ is compatible with explosive nucleosynthesis calculations. OSSE detected also a continuum below 200keV at better than 4σ confidence level with a flux of ~9x10^-4gamma/cm^2^/s/MeV at 100keV. This continuum can be fitted equally well with a power law, an exponential, or a thermal bremsstrahlung model. The implied temperature of kT=~35keV can be interpreted as the emission from the shocked circumstellar matter (CSM) by the primary blastwave of the supernova. Alternatively, the continuum can also be interpreted as bremsstrahlung from accelerated electrons that are also producing the observed radio emission.
Astronomy and Astrophysics Supplement Series
- Pub Date:
- December 1996
- GAMMA RAYS: OBSERVATIONS;
- ISM: INDIVIDUAL OBJECTS: CAS A;
- NUCLEAR REACTIONS;