Abstract

Contributed Talk - Splinter Galaxies

Friday, 11 September 2026, 16:15   (MW-0250)

Magnetohydrodynamic Simulations Dwarf Galaxies and Their Circumgalactic Medium Across Cosmic Time

Pei-Cheng Tung, Ke-Jung Chen
Academia Sinica Institute of Astronomy and Astrophysics (ASIAA)

In the quest to understand galaxy evolution, one of the missing pieces is the coevolution of dwarf galaxies and their circumgalactic medium (CGM), specifically how microphysics (e.g., magnetic fields) influences their physical properties and evolution. In our previous work (Tung & Chen 2025), hydrodynamical (HD) simulations quantitatively showed how gas accretion from the CGM drives star formation and the baryon cycle across redshifts. In this work, we present a suite of magnetohydrodynamical (MHD) simulations with updated subgrid mixing and AGN feedback models. We simulate six dwarf galaxy halos at z = 0, 1, 2, with initial conditions extracted from IllustrisTNG, each evolved for 1.2 Gyr. Compared to the HD simulations, the MHD runs show a higher star formation rate at z = 2, but a lower star formation efficiency and less bursty star formation across all redshifts. Although the magnetic energy budget is in general lower than the kinetic and thermal energy, our results reveal more filamentary but less metal-enriched CGMs. The baryon cycle follows the same redshift evolution trend, while the outflows are weaker compared to the HD simulations.