COMPTEL gamma-ray measurements of radioactivity in the galaxy

✍ Scribed by R. Diehl; A. Iyudin; U. Oberlack; V. Schönfelder; H. Bloemen; C. Dupraz; W. Hermsen; J. Knödlseder; J. Ryan; C. Winkler

• Publisher: Elsevier Science
• Year: 1997
• Tongue: English
• Weight: 243 KB
• Volume: 621
• Category: Article
• ISSN: 0375-9474
• DOI: 10.1016/s0375-9474(97)00216-9

✦ Synopsis

The COMPTEL imaging telescope has measured 7-ray lines originating from decay of the radioactive isotopes 28A1 and 44Ti: Imaging of the full sky in the 1.809 MeV line has presented a glow of nucleosynthesis from the plane of the Galaxy, yet with distinct irregularities on top of the expected emission from average nucleosynthesis. The measured sky profile can be understood as a composite of plausible sources. Alternatively, however, it may be interpreted as a mapping of regions of prominent nucleosynthetic activity from very massive stars. Current results favour massive stars as candidate sources, as supported from indications of spiral structure and from association of prominent emission with known massive-star rich regions. -The COMPTEL measurement of 44Ti gammarays from the Cas A supernova remnant presents the first detection of this isotope from supernova nucleosynthesis. Recent observations from CGRO Cycle 5 independently confirm the detection, consistent with previous results. With these data, further assessment of systematic effects is expected to yield a better absolute flux value from Cas A.