Precision Pollution - The effects of enrichment yields and timing on galactic chemical evolution

TL;DR

This paper updates a galaxy formation model to better understand how different enrichment mechanisms and their timing affect chemical abundance patterns in galaxies, considering various stellar yields, IMFs, and supernova delay models.

Contribution

It introduces an extended implementation of chemical enrichment processes in galaxy simulations, accounting for multiple mechanisms and their interactions in cosmological environments.

Findings

Prompt SNe Ia models yield higher [X/Fe] ratios.

Different delay-time-distributions affect [Fe/H] evolution.

Abundance patterns are similar at z=0 for some DTDs, but show systematic differences.

Abstract

We present an update to the chemical enrichment component of the smoothed-particle hydrodynamics model for galaxy formation presented in Scannapieco et al. (2005) in order to address the needs of modelling galactic chemical evolution in realistic cosmological environments. Attribution of the galaxy-scale abundance patterns to individual enrichment mechanisms such as the winds from asymptotic giant branch (AGB) stars or the presence of a prompt fraction of Type Ia supernovae is complicated by the interaction between them and gas cooling, subsequent star formation and gas ejection. In this work we address the resulting degeneracies by extending our implementation to a suite of mechanisms that encompasses different IMFs, models for yields from the aforementioned stars, models for the prompt component of the delay-time-distribution (DTDs) for Type Ia SNe and metallicity-dependent gas cooling rates, and then applying these to both isolated initial conditions and cosmological hydrodynamical zoom simulations. We find DTDs with a large prompt fraction (such as the bimodal and power-law models) have, at z=0, similar abundance patterns compared to the low-prompt component time distributions (uniform or wide Gaussian models). However, some differences appear, such as the former having systematically higher [X/Fe] ratios and narrower [O/Fe] distributions compared to the latter, and a distinct evolution of the [Fe/H] abundance.