CGR0 OSSE OBSERVATIONS OF THE CASSIOPEIA-A SUPERNOVA REMNANT/

Cassipeia A, the youngest known supernova remnant in the Galaxy and a strong radio and X-ray source, was observed by OSSE 1992 July 16-Augus t 6. Its close distance (similar to 3 kpc) and its young age (similar to 300 yr) make Cas A the best candidate among known supernova remnant s for detecting Ti-44 gamma-ray lines. We find no evidence of emission at 67.9 keV, 78.4 keV, or 1.157 MeV, the three strongest Ti-44 decay lines. From simultaneous fits to the three lines our 99% confidence up per limit to the flux in each line is 5.5 x 10(-5) gamma cm(-2) s(-1). We also report upper limits for the 4.44 MeV C-12 nuclear de-excitati on line, which could be produced by interactions of accelerated partic les in the supernova remnant, and for the hard X-ray continuum.