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 elusive, since its strength and direction are impossible to measure simultaneously. It is therefore essential that we complete our knowledge with numerical simulations of galaxy and magnetic field co-evolution.
In the first part of this talk, she will show results from a series of high-resolution numerical models, aimed at deciphering the effect of the initial conditions and of stellar feedback on the evolution of the galactic magnetic field in isolated, Milky Way-like galaxies. The models include a dark matter halo, a stellar and a gaseous disk, star formation and supernova feedback, so that the dynamical evolution of the galaxy is self-consistent. The galaxies develop a turbulent velocity field and a random magnetic field component very early in their evolution.
In the second part of the talk, she will show synthetic dust polarization maps taken from various locations within these simulated galaxies. As is done for the characterization of the Galactic foregrounds in observations of the thermal dust polarization sky, we use these maps to derive angular power spectra. By statistically comparing spectra taken from different locations and different models, we are able to quantify the effect of cosmic variance on the power spectral characteristics. We find that the polarization power spectra sensitively depend on the observer's location, impeding a distinction between different simulation setups.