SMM Observations of Interstellar 26Al: A Status Report
Abstract
The discovery of radioactive Al 26 in the interstellar medium has provided direct evidence for the recent nucleosynthesis of intermediate-mass nuclei in the Galaxy. While modern nucleosynthesis theories suggest that Al 26 production may occur in a variety of astrophysical objects, they have not been able to identify the dominant production site of the observed Al 26. Observationally, the greatest hope for identifying its source is through a comparison of the angular distribution of the 1.809 MeV radiation, emitted during the decay of Al 26, with the angular distributions of the suggested production sites. Limits on the distribution of the 1.809 MeV radiation have been obtained from data collected by the Solar Maximum Mission Gamma-Ray Spectrometer by using the Earth as an occulting disk in its large field-of-view. These limits are: (1) the data are inconsistent with a point source origin of 1. 809 MeV radiation located at l=0 deg, b= 0 deg at the 4.7 sigma confidence level; (2) the angular diameter for a uniform face-on disk distribution centered at l=0 deg, b= 0 deg is > 10 deg at the 4.1 sigma confidence level; and (3) the data are consistent with each of the diffuse distribution models studied representing Al 26 production by many individual events occurring throughout the Galaxy.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 1988
- Accession Number
- ADA236222
Entities
People
- G. H. Share
- M. P. Ulmer
- R. L. Kinzer
- W. R. Purcell
Organizations
- Northwestern University