Tgrs Measurements of the Positron Annihilation Spectrum from the Galactic Center
نویسندگان
چکیده
We have obtained spectra of the Galactic center at energies 400–600 keV from high-resolution data acquired by the TGRS Ge spectrometer on board the WIND mission during 1995–1997. The data were obtained using an on-board occulter, and are relatively free from systematics and backgrounds. Analysis of the spectra reveals a well-resolved electron-positron annihilation line at 511 keV and the associated continuum due to annihilation via positronium formation. Measurements of the line width and the continuum-to-line ratio allow some constraints to be placed on the interstellar sites where annihilation occurs. Subject headings: gamma rays: observations — Galaxy: center
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