SIMBA-C: An updated chemical enrichment model for galactic chemical evolution in the SIMBA simulation

TL;DR

SIMBA-C is an advanced chemical enrichment model integrated into the SIMBA galaxy formation simulation, improving predictions of galaxy properties and chemical abundances by tracking 34 elements without assuming instantaneous recycling.

Contribution

It introduces a detailed chemical evolution model into SIMBA, enhancing the accuracy of galaxy and chemical abundance predictions over previous models.

Findings

Improves the galaxy stellar mass function and main sequence predictions.

Better matches the observed mass-metallicity relation at multiple redshifts.

Provides more accurate galactic abundance ratios like [O/Fe] and [N/O].

Abstract

We introduce a new chemical enrichment and stellar feedback model into GIZMO, using the SIMBA sub-grid models as a base. Based on the state-of-the-art chemical evolution model of Kobayashi et al., SIMBA-C tracks 34 elements from H$\rightarrow$Ge and removes SIMBA's instantaneous recycling approximation. Furthermore, we make some minor improvements to SIMBA's base feedback models. SIMBA-C provides significant improvements on key diagnostics such as the knee of the $z=0$ galaxy stellar mass function, the faint end of the main sequence, and the ability to track black holes in dwarf galaxies. SIMBA-C also matches better with recent observations of the mass-metallicity relation at $z=0,2$. By not assuming instantaneous recycling, SIMBA-C provides a much better match to galactic abundance ratio measures such as [O/Fe] and [N/O]. SIMBA-C thus opens up new avenues to constrain feedback models using detailed chemical abundance measures across cosmic time.