Galaxy evolution strongly depends on the physics of the interstellar medium (ISM). The ISM is permeated by magnetic fields (B-fields), in which magnetic energy is in close equipartition with the thermal and kinetic energy. This physical condition makes the B-fields dynamically important at several stages of galaxy evolution, affecting gas flows in the ISM and driving gas inwards toward the galaxy’s center and outwards toward the circumgalactic medium via galactic outflows, as well as the star formation history of galaxies. Thus, B-fields are an important, but still overlooked, ingredient to understanding the evolution of galaxies across cosmic time.

Far-infrared and sub-mm wavelengths have recently been key to providing a complete picture of extragalactic magnetism by doing what only HAWC+/SOFIA, JCMT/POL-2, and ALMA can do: measuring B-fields in the densest areas of the Universe. Using FIR/Sub-mm and radio polarimetric observations, in combination with the kinematics of the neutral and molecular gas, we have performed a tomographic study of B-field in galaxies for the first time. In this talk, I will present the results of SALSA (Survey for extragALactic magnetiSm with SOFIA Legacy Program): the magnetic properties in the multi-phase ISM at 100s pc scales of nearby galaxies (e.g., spirals, starbursts, mergers) observed in the wavelength range of 50-890 um. Then, I’ll present the furthermost B-field measured in a gravitationally lensed dusty star-forming galaxy at z=2.6 using ALMA polarimetry and how this can be used as a new probe to quantify how B-fields have evolved over cosmic time. I will finalize presenting the future projects using SALSA and ALMA to characterize the multi-phase ISM in nearby and early Universe galaxies and with its synergy with the next generation of NASA missions.