Abstract :
The evolution of galaxies is controlled by a delicate interplay between gravity, turbulence, feedback, and magnetic fields. Although most current empirical and theoretical approaches to understanding this interplay are mainly focused on gravitational forces and gas dynamics, magnetic fields indeed play a fundamental role in the interstellar medium (ISM), galactic dynamics, galactic winds, and intergalactic medium (IGM). Galaxies are known to host large-scale magnetic fields along the spiral arms, have magnetic field strengths of ~uG with similar contributions from the random and ordered magnetic field components, and have magnetic fields oriented along galactic outflows that are likely responsible for magnetizing the IGM. To date, these results have mostly emerged from single wavelength regimes: radio synchrotron polarization tracing the magnetic field structure in the ionized gas, and optical studies to investigate the effect of scattering and/or extinction by the ISM. These studies access the magnetic fields on vastly different spatial scales and only for the diffuse ISM. SOFIA is key to provide a complete picture of extragalactic magnetism by doing what only HAWC+ can do: measuring magnetic fields in the densest areas of the universe. I will present the first results of a SOFIA Legacy Program to observe extragalactic magnetic fields by means of magnetically aligned dust grains in the dense ISM of a sample of nearby galaxies. We have detected 1) a spiral magnetic field across the galactic disk of NGC 1068, 2) a magnetic field tightly following the molecular warped disk of Centaurus A, and 3) magnetic fields along the outflows of the starburst galaxy M82. These results open a new window of exploration on galaxy evolution.
