Evidence for sub-Chandrasekhar Type Ia supernovae from the last major merger

ABSTRACT We investigate the contribution of sub-Chandrasekhar mass Type Ia supernovae to chemical enrichment Gaia Sausage galaxy, progenitor a significant merger event in early life Milky Way. Using combination data from Nissen & Schuster, GALactic Archaeology with HERMES (GALAH) Data Release 3 [with 1D non-local thermal equilibrium (NLTE) abundance corrections], and Apache Point Observatory Galactic Evolution Experiment (APOGEE) 16, we fit analytic evolution models nine-dimensional space (Fe, Mg, Si, Ca, Cr, Mn, Ni, Cu, Zn) particular focusing on iron-peak elements, Mn Ni. find that low [Mn/Fe] $\sim -0.15\, \mathrm{dex}$ [Ni/Fe] -0.3\, yields are required explain observed trends beyond [?/Fe] knee (approximately at [Fe/H] $=-1.4\, \mathrm{dex}$). Comparison theoretical yield calculations indicates this system (from ${\sim} 60\, \mathrm{per\, cent}$ $100\, depending model an additional ${\pm} 10\, systematic NLTE corrections). compare results other Local Group environments including dwarf spheroidal galaxies, Magellanic Clouds, Way’s bulge, finding must be metallicity dependent. Our suggest channels significant, perhaps even dominant, metal-poor systems, whilst more metal-rich systems could explained by metallicity-dependent yields, possibly variation related star formation history, or increased Chandrasekhar higher metallicity.