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-August 6. Its close distance (∼3 kpc) and its young age (∼300 yr) make Cas A the best candidate among known supernova remnants for detecting 44Ti γ-ray lines. We find no evidence of emission at 67.9 keV, 78.4 keV, or 1.157 MeV, the three strongest 44Ti decay lines. From simultaneous fits to the three lines our 99% confidence upper limit to the flux in each line is 5.5 × 10-5 γ cm-2 s -1 We also report upper limits for the 4.44 MeV 12C nuclear de-excitation line, which could be produced by interactions of accelerated particles in the supernova remnant, and for the hard X-ray continuum.
- Gamma rays: observations
- ISM: indvidual (Cassiopeia A)
- Nuclear reactions, nucleosynthesis, abundances
- Supernova remnants
ASJC Scopus subject areas
- Astronomy and Astrophysics
- Space and Planetary Science