Constraining SN Ia progenitors from the observed Fe-peak elemental abundances in the Milky Way dwarf galaxy satellites

ABSTRACT Chemical abundances of iron-peak elements in the red giants of ultra-faint dwarf galaxies (UFDs) and dwarf spheroidal galaxies (dSphs) are among the best diagnostics in the cosmos to probe the origin of Type Ia supernovae (SNe Ia). We incorporate metallicity-dependent SN Ia nucleosynthesis models for different progenitor masses in our inhomogeneous galactic chemical evolution model, i-GEtool, to recreate the observed elemental abundance patterns and their spread in a sample of UFD and dSph galaxies with different average metallicities and star formation histories. Observations across different environments indicate that both [Ni/Mg] and [Mn/Mg] increase on average with metallicity, with the latter having a higher slope. The average dispersion of [X/Mg] from our UFD model ranges between 0.20 and 0.25 for iron-peak elements, with the exception of [Sc/Mg] that has $\sigma \approx 0.39$. Chemical evolution models assuming Chandrasekhar mass ($M_{\text{ch}}$) SN Ia progenitors produce similar [Ni/Mg]–[Fe/H] and [Mn/Mg]–[Fe/H] abundance patterns to those observed in the examined UFD and dSph galaxies, without the need to invoke a substantial fraction of sub-$M_{\text{ch}}$ progenitors that change across different environments, as claimed by some previous chemical evolution studies. Sub-$M_{\text{ch}}$ progenitors in our dSph models underproduce both [Ni/Mg]–[Fe/H] and [Mn/Mg]–[Fe/H] abundance patterns. We stress on the importance of accounting for inhomogeneous chemical enrichment and metallicity-dependent SN Ia yields, which are the main aspects that distinguish our work from the previous chemical evolution studies of iron-peak elements.