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[6.01] RHESSI Observations of Galactic Gamma-Ray Lines

D. M. Smith (Space Sciences Laboratory, U. C. Berkeley)

The Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI) has been in low-Earth orbit since February 5, 2002, performing imaging spectroscopy of solar flares in the hard x-ray and gamma-ray range. RHESSI's high-resolution germanium detectors are unshielded and collect photons above approximately 100 keV from the whole sky. By using the Earth as an occulter, we can make a background-subtracted spectrum of the inner Galaxy. We see the 1809 keV line from ²⁶Al with 11 sigma significance in data accumulated through December 1, 2002. The width of the line is 2.03 (+0.78, -1.21) keV, disagreeing with the 5.4 keV width reported by the GRIS balloon. I will present updated results on this line and discuss the status of the search for the lines from ⁶⁰Fe in the Galactic spectrum. This work is supported by NASA contract NAS5-98033.

Bulletin of the American Astronomical Society, 35#2
© 2003. The American Astronomical Soceity.