COMPTEL observations of Ti-44 gamma-ray line emission from CAS A
Publication date: 16 April 1994
Authors: Iyudin, A.F. et al.
Journal: Astronomy and Astrophysics
Copyright: European Southern Observatory
The Compton Telescope (COMPTEL) telescope aboard the Compton Gamma-Ray Observatory (CGRO) is capable of imaging gamma-ray line sources in the MeV region with a sensitivity of the order 10-5 photons/(cm²s). During two observations periods in July 1992 and February 1993 the Galactic plane in the region of the young supernova remnant Cas A was observed, showing evidence for line emission at 1.16 MeV from the decay of 44Ti at a significance level of approximately 4 sigma. This is the first time a supernova remnant has been detected in the gamma-ray line from 44Ti decay. Adopting a distance of 2.8 kpc to the Cas A remnant, the measured line flux (7.0 +/- 1.7) x 10-5 photons/(cm²s), can be translated into a 44Ti mass ejected during the Cas A supernova explosion, between (1.4 +/- 0.4) x 10-4 solar mass and (3.2 +/- 0.8) x 10-4 solar mass, depending on the precise value of the 44Ti mean life time and on the precise date of the event. Implications of this result for supernova nucleosynthesis models are discussed.Link to publication