Gamma-ray lines

Figure 16.24. Sensitivity of upcoming gamma-ray telescopes to neutralino models that can explain the HEAT positron excess with neutralino clumps in the galactic halo. Model points are indicated by crosses circles denote those models that in addition can also account for the measured deviation in the muon magnetic moment. The upper set of sensitivity curves corresponds to the high latitude gamma-ray line flux (scale on the left) the lower set of curves to the direction toward the galactic center (scale on the right no steep spike around the central black hole is assumed). (Figure from Baltz, Edsjo, Freese, Gondolo(2002).)...

Harris, M.J., Teegarden, B.J., Weidensbointner, G., Palmer, D.M., Cline, T.L., Gehrels. N. Ramaty, R. 2001 Transient Gamma-ray spectrometer observations of Gamma-ray lines from Novae. III. The 478 keV line from 7Be decay. ApJ 563, 950. 

Gamma-ray, X-ray, optical and infrared line spectroscopy of SNe and SNRs have been used to observe nucleosynthesis and the abundance distribution of elements freshly synthesized (both radioactive isotopes and stable decay products) and to extract dynamical information about the explosion. In particular the radioactive isotopes provide unique tracers of nucleosynthetic processes (what, where and how much) and its related dynamics. The best examples are the observations of gamma-ray lines in supernovae, but X-ray line spectroscopy of decay products of radioactive nuclei have also been attempted, and specific elements in numerous SNRs and a few SNe identified. 

A considerable number of sources have been discovered from which the emission spectrum is dominated by discrete gamma-ray line features. As is discussed elsewhere at this meeting [7] the detailed spectroscopy of the associated line shapes, intensities etc. yields vital diagnostic information on the physical conditions at the source region. Here we briefly review the likely spatial distributions on the sky and evaluate the imaging requirements which must be associated with the fine spectroscopy measurements, if the full astrophysical information is to be extracted. 

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