Hard X- and Gamma-Rays from Type Ia Supernovae

Abstract

The gamma-ray light curves and spectra are presented for a set of theoretical Type Ia supernova models including deflagration, detonation, delayed detonation, and pulsating delayed detonations of Chandrasekhar mass white dwarfs as well as merger scenarios that may involve more than the Chandrasekhar mass and helium detonations of sub-Chandrasekhar mass white dwarfs. The results have been obtained with a Monte Carlo radiation transport scheme which takes into account all relevant gamma-transitions and interaction processes. The result is a set of accurate line profiles which are characteristic of the initial Ni-mass distribution of the supernova models. The gamma-rays probe the isotopic rather than just the elemental distribution of the radioactive elements in the ejecta. Details of the line profiles including the line width, shift with respect to the rest frame, and line ratios are discussed. With sufficient energy and temporal resolution, different model scenarios can clearly be distinguished. Observational strategies are discussed for current and immediately upcoming generations of satellites (CGRO and INTEGRAL) as well as projected future missions including concepts such as Laue telescopes. With CGRO, it is currently possible with sufficiently early observations (near optical maximum) to distinguish helium detonations from explosions of Chandrasekhar mass progenitors and of those involving mergers up to a distance of about 15 Mpc. This translates into one target of opportunity every eight years. SNe Ia up to about 10 Mpc would allow detailed CGRO studies of line ratios of Co lines.