2024/08/14 by Alexander, Ryan K., Vincenzo, Fiorenzo
#Astrophysics of Galaxies (astro-ph.GA) #FOS: Physical sciences
paper · doi:10.48550/arxiv.2408.07443
Chemical abundances of iron-peak elements in the red giants of ultra-faint dwarf galaxies (UFD) and dwarf spheroidal galaxies (dSph) 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, \tti-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 [Mn/Mg] increases on average with metallicity while [Ni/Mg] remains nearly constant. 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 σ≈ 0.39. Chemical evolution models assuming Chandrasekhar mass (MCh) SN Ia progenitors produce similar [Mn/Mg]-[Fe/H] and [Ni/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-Mch progenitors that change across different environments, as claimed by some previous chemical evolution studies. Sub-Mch progenitors in our dSph models under produce both [Ni/Mg]-[Fe/H] and [Ni/Mg]-[Fe/H] abundance patterns, with the 1 M\odot sub-Mch model explaining a number of outliers in [Ni/Mg]-[Fe/H], while the outliers in [Mn/Mg]-[Fe/H] require higher sub-Mch progenitor masses.