Abstract

Contributed Talk - Splinter Multimessenger

Constraining Cosmic Ray Feedback in Galaxy Evolution

Maria Werhahn
Max Planck Institute for Astrophysics (MPA)

Cosmic rays (CRs) are ubiquitous in the interstellar medium of the Milky Way and nearby galaxies and are thought to play an essential role in governing their evolution. However, many of their properties remain poorly constrained. Since direct measurements of CRs are limited to our local environment, observations of radio and gamma-ray emission arising from CRs provide a powerful tool to constrain their transport properties and interactions with the ISM in other galaxies. To better understand the link between observational signatures and CR physics, we use a series of MHD simulations with AREPO including CRs, complemented by post-processing to model CR spectra and their multi-frequency emission. These simulations have enabled us to identify the processes required to simultaneously reproduce observed correlations and spectra of star-forming galaxies in the radio and gamma-ray regimes. Building on this, we are applying this framework to cosmological zoom simulations to explore how environmental factors—such as magnetic field strengths and host interactions—impact CR-related observables. Additionally, by incorporating more detailed modelling of CR electrons and tracking their spectral evolution in time, we aim to assess the validity of the steady-state assumption commonly used in interpreting radio and gamma-ray observations. This will allow us to evaluate how these assumptions influence our understanding of the underlying CR physics and magnetic field properties and provide an invaluable link between theory and observations.