The Role of Magnetic Fields in The Evolution of Galaxies

Magnetic fields constitute an energetic component of the interstellar medium in galaxies and hence can affect the formation of galactic structures. Sensitive resolved radio continuum observations together with statistical studies in galaxy samples are performed to investigate the origin and the impact of the magnetic fields. The JVLA cloud-scale survey of the local group galaxy, M33, unveils strong tangled magnetic field along the spiral arms and in the galaxy center indicating amplification due to compression and local shear in molecular clouds. Studying a sample of non-cluster, non-interacting galaxies, we find that the large-scale ordered magnetic field scales with the rotation speed of galaxies. The total and disordered magnetic fields scales with the star formation rate in normal star forming galaxies. On the other hand, a strong magnetic field in the center of NGC 1097 -- a massive galaxy undergoing quenching -- is found responsible for decelerating its massive star formation. Putting these results together, it is deduced that 1) the Universe was highly magnetized short after the peak of the massive star birth at about 1 Gyr after the Big Bang and 2) the strong magnetic field has possibly acted as back reaction after this time, quenching the massive star formation and stimulating the creation of low-mass stars in massive galaxies.