Thermonuclear Supernovae as a Source of Galactic Positrons

We present a study on the emission of positrons from Type Ia Supernovae (SNe~Ia). We evaluate their escape fractions and energy spectra and then address their role in the Galactic positron puzzle. Our simulations encompass a wide variety of explosion scenarios, including the explosion of Chandrasekhar mass limit ($M_{\mathrm{Ch}}$) white dwarfs (WD), He-triggered explosions of sub-$M_{\mathrm{Ch}}$ WDs, and dynamical mergers of two WDs. For each model, we study the influence of the size and morphology of the progenitor magnetic field between 1 and $10^{13}$ G. Based on the observed brightness distribution of SNe~Ia, we find that the resulting positron injection is dominated by normal bright SNe~Ia, which may reduce the dependence on the explosion mechanism. The morphology of the progenitor B-field dominates the positron escape at about $(1.96 \pm 0.75)$ and $(0.94 \pm 0.56) \times 10^{52}$ e$^{+}$ per SN~Ia for large scale dipole and turbulent fields, respectively. Assuming a Galactic SN~Ia rate between $0.13$ and $ 0.76$ per century, we find positron injection rate ranges from (0.48 to 6.42) and (0.20 to 3.91) $\times 10^{42}$ e$^{+}$~s$^{-1}$ for dipole and turbulent fields, respectively. SNe~Ia may be contributed to $\approx 1-13\%$ of the Galactic positron annihilation rate.