Next Talk (24 April 2024)

Magnetic fields and feedback: shaping the galactic ISM

Magnetic fields are of paramount importance for understanding the evolution and dynamics of galaxies. However, even the magnetic field of our own Galaxy is still largely a mystery, since its strength and direction are impossible to measure simultaneously. It is therefore essential that we complete our knowledge with numerical simulations of galactic and magnetic field co-evolution. I will present a series of high-resolution numerical models aimed at deciphering the effect of the initial conditions and of stellar feedback on the ISM dynamics in isolated, Milky Way-like galaxies. The models include a dark matter halo, a stellar and a gaseous disk, star formation and supernova feedback, together with an initial magnetic field of varying strength and morphology, so that the dynamical evolution of the galaxy is self-consistent. Independently of the initial conditions, the galaxies develop a turbulent velocity field and a random magnetic field component very early in their evolution. Supernova feedback is extremely efficient in building a random magnetic field component up to large galactic heights, but a random magnetic field emerges even in runs without feedback, which points to inherent instabilities of the ordered component. Finally, I will present synthetic magnetic field observables, such as polarization and Faraday rotation maps deduced from these models, showing the local and global effects of feedback over time on the various probes of the galactic magnetic field.

3pm in C214