The dynamical impact of cosmic rays in Milky Way-like galaxies

Karin Kjellgren

Thursday, Dec. 5th, 14:20CET

Cosmic rays (CRs) play a crucial role in shaping the interstellar medium (ISM). Accelerated in supernova (SN) shocks, CRs propagate along magnetic field lines, distributing energy and momentum throughout the galaxy. This process ionizes and heats the gas and drives galactic outflows by creating pressure gradients away from the disk, all of which can help regulate and suppress star formation. We perform high-resolution magnetohydrodynamical simulations of Milky-Way-like galaxies, in which we follow individual massive stars and include self-consistent stellar feedback such as SNe and CRs, dynamically coupled to the MHD equations. We model the multi-phase interstellar medium using a non-equilibrium chemical network that includes hydrogen and carbon species, allowing us to take into account the relevant cooling and heating processes and compare the simulations to observations. In this work, we present the effects of thermal and CR feedback on the galactic structure and gas dynamics across different ISM phases. We highlight how CRs impact the thermal phase and structure of outflows and fountain flows across the galaxy, from the Galactic Center to the solar neighborhood and beyond. Finally, we demonstrate how recent star formation shows up in gamma-ray emission maps produced by CR interactions.