May 28th, 2026 4:00pm ET

The Effect of Various Physical Processes on Gas Flows in the CGM

https://science.nasa.gov/astrophysics/programs/cosmic-origins/community/dgce-sig-seminar-28-may-2026

Speaker

Freeke van de Voort, Cardiff University

Abstract

Feedback-driven outflows are vital for creating realistic galaxies, but feedback models implemented in cosmological simulations vary wildly. The circumgalactic medium (CGM) may be able to break degeneracies and constrain these models. However, there are other differences between simulation efforts, such as which physical processes are included and which numerical method is used. Without understanding their impact on the CGM, we will not be able to confidently constrain galaxy formation models. Using zoom-in cosmological simulations, I will discuss some of the physical and observable properties of the CGM. I will focus on non-thermal physical processes and how they impact the galactic ecosystem. The presence of magnetic fields and feedback from relativistic cosmic rays changes the flow of gas in the CGM, affecting the efficiency of outflows driven by stars or supermassive black holes as well as the turbulence-driven mixing in the CGM. This also affects our simulations’ predictions for neutral hydrogen and metal ions. I will show how these effects of magnetic fields and cosmic rays vary across a wide range in halo mass, from dwarf galaxies to galaxy groups. Briefly switching focus to a thermal process, I will show preliminary results from our work on thermal conduction in groups and clusters.