https://www.scientificamerican.com/article/swirling-magnetic-fields-hint-at-origins-of-spiral-galaxy-shapes/

Galaxies in the universe come in all shapes and sizes. Some are giant spheres of stars many times larger than the Milky Way. Others are flattened disks, with pancakelike stellar swirls orbiting a central bulge. But others still, including our own, are arrangements of stars that dance in spirals around their center. Astronomers have long puzzled over how these spirals form, and a number of theories have been proposed. Now new observations are revealing the galactic-scale magnetic fields associated with these spirals, providing what may be vital clues to their formation.

In a paper posted on the preprint server arXiv.org and accepted for publication in the Astrophysical Journal, a team of astronomers performed observations from NASA’s Stratospheric Observatory for Infrared Astronomy (SOFIA), a telescope that files on a modified Boeing jet, to observe a galaxy called M77 with a new instrument called the High-Resolution Airborne Wideband Camera–Plus (HAWC+). Although M77 is some 47 million light-years from Earth, the team was able to use SOFIA’s far-infrared capabilities to observe the its magnetic field, finding it closely correlated with the galaxy’s star-filled spiral arms.