Core to Cosmic Edge: SIMBA-C's New Take on Abundance Profiles in the Intragroup Medium at z = 0

TL;DR

This study uses the SIMBA-C simulation to analyze how an upgraded chemical enrichment model affects metal distribution in galaxy groups, showing improved agreement with observations but highlighting the need for better feedback and mixing models.

Contribution

Introduces the SIMBA-C simulation with Chem5 enrichment model, demonstrating its impact on metal profiles and group properties compared to previous models.

Findings

SIMBA-C produces flatter, lower-amplitude abundance profiles aligning better with observations.

Over-enrichment of certain elements in low-mass groups indicates modeling limitations.

Reduced metal yields and feedback changes lower IGrM metal content in SIMBA-C.

Abstract

We employ the SIMBA-C cosmological simulation to study the impact of its upgraded chemical enrichment model (Chem5) on the distribution of metals in the intragroup medium (IGrM). We investigate the projected X-ray emission-weighted abundance profiles of key elements over two decades in halo mass ($10^{13} \leq M_{500}/\mathrm{M_\odot} \leq 10^{15}$). Typically, SIMBA-C generates lower-amplitude abundance profiles than SIMBA with flatter cores, in better agreement with observations. For low-mass groups, both simulations over-enrich the IGrM with Si, S, Ca, and Fe compared to observations, a trend likely related to inadequate modeling of metal dispersal and mixing. We analyze the 3D mass-weighted abundance profiles, concluding that the lower SIMBA-C IGrM abundances are primarily a consequence of fewer metals in the IGrM, driven by reduced metal yields in Chem5, and the removal of the instantaneous recycling of metals approximation employed by SIMBA. Additionally, an increased IGrM mass in low-mass SIMBA-C groups is likely triggered by changes to the AGN and stellar feedback models. Our study suggests that a more realistic chemical enrichment model broadly improves agreement with observations, but physically motivated sub-grid models for other key processes, like AGN and stellar feedback and turbulent diffusion, are required to realistically reproduce observed group environments.