Progenitor-mass-dependent yields amplify intrinsic scatter in dwarf-galaxy elemental abundance ratios

TL;DR

This study uses detailed, progenitor-mass-dependent yields in dwarf galaxy simulations, revealing that such explicit modeling significantly increases the intrinsic scatter in elemental abundance ratios, aligning better with observations.

Contribution

It introduces progenitor-mass-dependent nucleosynthetic yields into dwarf galaxy simulations, highlighting their impact on elemental abundance scatter.

Findings

Mass-dependent yields widen [Fe/H]-[$eta$/Fe] scatter.

NuGrid yields produce lower overall $eta$-element levels.

Explicit yields may explain observed abundance variations.

Abstract

In hydrodynamic simulations, prevailing subgrid chemical-evolution models often use a single, "IMF-averaged" supernova yield, ignoring variations in elemental abundance ratios (particularly [$\alpha$/Fe]) in the ejecta of higher- and lower-mass supernova progenitors within a stellar population. To understand the impact of this simplification and understand the impact of more explicit models, we run FIRE simulations of a dwarf galaxy $(M_\star($z = 0$) \sim 10^6 M_\odot)$ using nucleosynthetic yields from the NuGrid database that depend on the stellar progenitor mass and metallicity. While NuGrid exhibits lower aggregate $\alpha$-element production than default-FIRE yields, we find that its explicit mass dependence substantially widens the intrinsic scatter in the simulated [Fe/H]-[$\alpha$/Fe] -- a phenomenon potentially visible in recent observations of dwarf galaxies.