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Topic

Simulating the Chemical Enrichment of the Intra-Group Medium

Department of Physics and Astronomy

Date & location

• Monday, April 7, 2025
• 8:30 A.M.
• Clearihue Building, Room B017

Examining Committee

Supervisory Committee

• Dr. Arif Babul, Department of Physics and Astronomy, University of Victoria (Supervisor)
• Dr. Jon Willis, Department of Physics and Astronomy, UVic (Member)

External Examiner

• Dr. Veronica Biffi, Astronomical Observatory of Trieste, Italian National Institute for Astrophysics

Chair of Oral Examination

• Dr. Irina Paci, Department of Chemistry, UVic

Abstract

This thesis investigates the chemical enrichment of the intragroup medium (IGrM) using cosmological simulations. Specifically, I compare results from the simba and simba-c simulations, focusing on the distribution of metal abundances in galaxy groups. simba-c incorporates an updated and more realistic chemical enrichment and stellar feedback model (Chem5), leading to notable differences in IGrM abundances compared to simba. I examine projected emission-weighted abundance profiles, finding that simba-c generally produces lower-amplitude abundance profiles with flatter cores, aligning better with observational data across a range of X-ray relevant metals. However, the agreement between simulations and observations for both simba-c and simba worsens with decreasing group mass through an increase in the amplitudes of the simulated abundance profiles relative to those of the observed profiles; this agreement is also somewhat sensitive to the specific element under consideration. Moreover, I investigate the 3D mass-weighted abundance profiles to deepen my understanding of the physical mechanisms driving the changes found between simba and simba-c and between low and high mass groups. The results indicate that simba-c enriches the IGrM to a lesser degree than simba across all studied metals and mass scales, and produces less total metal mass in the hot diffuse phase. I ascribe these features to reduced metal yields in Chem5 compared to simba and the replacement of simba’s instantaneous enrichment model with Chem5 in simba-c. On the other hand, simba-c actually contains more total hot gas mass in low mass groups than does simba, which may be due to slight changes in the stellar and AGN feedback models. My study reveals that accurate sub-grid models for metal dispersal and mixing processes are required to realistically reproduce observed group environments in cosmological simulations.