Gamma emission from type ia supernovaesimulation, analysis and detection

Abstract

Supernovae (SNe) are powerful stellar explosions that highlight the end of the life of some stars. Type Ia supernovae (SNe Ia) are a type of SNe originated by thermonuclear runaway in a white dwarf. This thesis is devoted to the study of SNe Ia and their gamma-ray emission with the goal to study how to improve the knowledge about this phenomenon. In the first chapter, we make an overview of SNe, focusing in SNe Ia. We explain what we currently know about these type of SNe and which are the hypothesis that try to explain their explosion mechanism and progenitor system. We explain that gamma-rays from SNe Ia can work as diagnostic tools. The second chapter describes the creation of a code that simulate the transport of gamma photons during the expansion phase of SN Ia in a 3D Cartesian grid. The code is based in Monte Carlo's techniques and the theory of indivisible energy packets. The goal of the code is to simulate the synthetic observables of theoretical scenarios of SNe Ia. In the third chapter, we simulate multiple scenarios of SNe Ia with different composition and asymmetries to analyse their synthetic observables. The experiments focus on placing 56Ni on different locations of the ejecta and creating asymmetries. The results show how a favourable line of sight allows to distinguish their signatures at early days until day ~35. The experiments with 56Ni close to the surface display emission lines at ~15 days after the explosion. Moreover, the 0.158 MeV line allows us to determine if 56Ni was in the surface of the model. The light curves of models with 56Ni close to the surface have a rapid rise of their flux. In particular, the test with an outer plume of 56Ni displays a peak around the ~9th day, which agrees with the mean lifetime decay of 56Ni. The tests with 48Cr display lines from its daughter nucleus, 48V, at day ~15. Especially, 0.983 MeV and 1.312 MeV lines. The light curves of the models with 48Cr display a faster rise and a faster decline than the ones without. Finally, in the last chapter we describe a detailed analysis that studies the sensitivity of the anticoincidence system (ACS) of the spectrometer SPI on board of the INTEGRAL space observatory for detecting the early gamma-ray emission of a galactic SN Ia as a function of the explosion model, distance and pointing direction. The results suggest that the detection is possible at about 6 - 12 days after the explosion and, at the same time, we can discard missing any hidden explosion during the lifetime of the mission.