PROSPECTS FOR TYPE IA SUPERNOVA EXPLOSION MECHANISM IDENTIFICATION WITH GAMMA-RAYS

The explosion mechanism associated with thermonuclear supernovae (SNIa ) is still a matter of debate. There is a wide agreement that high amo unts of radioactive nuclei are produced during these events and they a re expected to be strong gamma-ray emitters. In the past, several auth ors have investigated the use of this gamma-ray emission as a diagnost ic tool. In this paper we have performed a complete study of the gamma -ray spectra associated with all the different scenarios currently pro posed. This includes detonation, delayed detonation, deflagration and the off-centre detonation. We have performed accurate simulations for this complete set of models in order to determine the most promising s pectral features that could be used to discriminate among the differen t models. Our study is not Limited to qualitative arguments. Instead, we have quantified the differences among the spectra and established d istance limits for their detection. The calculations have been perform ed considering the best current response estimations of the SPI and IB IS instruments aboard INTEGRAL in such a way that our results can be u sed as a guideline to evaluate the capabilities of INTEGRAL in the stu dy of Type Ia supernovae. For the purpose of completeness we have also investigated the nuclear excitation and spallation reactions as a pos sible secondary source of gamma-rays present in some supernova scenari os. We conclude that this mechanism can be neglected because of its sm all contribution.