# Chemical evolution of disc galaxies from cosmological simulations

## TL;DR

This study uses cosmological hydrodynamical simulations to explore how different assumptions about initial mass functions, stellar yields, and binary systems influence the chemical evolution and metallicity distribution in disc galaxies.

## Contribution

It systematically compares the effects of various IMFs, stellar yields, and binary fractions on galaxy chemical properties, providing insights into model choices that best match observations.

## Key findings

- Kroupa et al. (1993) IMF fits late-type galaxy observations.
- Kroupa (2001) IMF aligns better with Milky Way stellar metallicity and alpha-enhancement.
- Binary fraction of 0.03 for SNe Ia reproduces observed SN rates and alpha-enhancement.

## Abstract

We perform a suite of cosmological hydrodynamical simulations of disc galaxies, with zoomed-in initial conditions leading to the formation of a halo of mass $M_{\rm halo, \, DM} \simeq 2 \cdot 10^{12}$ M$_{\odot}$ at redshift $z=0$. These simulations aim at investigating the chemical evolution and the distribution of metals in a disc galaxy, and at quantifying the effect of $(i)$ the assumed IMF, $(ii)$ the adopted stellar yields, and $(iii)$ the impact of binary systems originating SNe Ia on the process of chemical enrichment. We consider either a Kroupa et al. (1993) or a more top-heavy Kroupa (2001) IMF, two sets of stellar yields and different values for the fraction of binary systems suitable to give rise to SNe Ia. We investigate stellar ages, SN rates, stellar and gas metallicity gradients, and stellar $\alpha$-enhancement in simulations, and compare predictions with observations. We find that a Kroupa et al. (1993) IMF has to be preferred when modelling late-type galaxies in the local universe. On the other hand, the comparison of stellar metallicity profiles and $\alpha$-enhancement trends with observations of Milky Way stars shows a better agreement when a Kroupa (2001) IMF is assumed. Comparing the predicted SN rates and stellar $\alpha$-enhancement with observations supports a value for the fraction of binary systems producing SNe Ia of $0.03$, at least for late-type galaxies and for the considered IMFs. Adopted stellar yields are crucial in regulating cooling and star formation, and in determining patterns of chemical enrichment for stars, especially for those located in the galaxy bulge.