2008MNRAS.385.1681S

A multidimension, time-dependent Monte Carlo code is used to compute sample γ-ray spectra to explore whether unambiguous constraints could be obtained from γ-ray observations of Type Ia supernovae. Both spherical and aspherical geometries are considered and it is shown that moderate departures from sphericity can produce viewing-angle effects that are at least as significant as those caused by the variation of key parameters in 1D models. Thus, γ-ray data could, in principle, carry some geometrical information, and caution should be applied when discussing the value of γ-ray data based only on 1D explosion models. In light of the limited sensitivity of current γ-ray observatories, the computed theoretical spectra are studied to revisit the issue of whether useful constraints could be obtained for moderately nearby objects. The most useful γ-ray measurements are likely to be of the light curve and time-dependent hardness ratios, but sensitivity higher than currently available, particularly at relatively hard energies (∼2-3MeV), is desirable.