SPI measurements of Galactic 26Al

The precision measurement of the 1809 keV gamma-ray line from Galactic 26 Al is one of the goals of the SPI spectrometer on INTEGRAL with its Ge detector camera. We aim for determination of the detailed shape of this gamma-ray line, and its variation for dierent source regions along the plane of the Galaxy. Data from the first part of the core program observations of the first mission year have been inspected. A clear detection of the 26 Al line at'5-7 significance demonstrates that SPI will deepen 26 Al studies. The line intensity is consistent with expectations from previous experiments, and the line appears narrower than the 5.4 keV FWHM reported by GRIS, more consistent with RHESSI's recent value. Only preliminary statements can be made at this time, however, due to the multi-component background underlying the signal at'40 times higher intensity than the signal from Galactic 26 Al.

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