Mergers appear to yield disk-shaped galaxies, contrary to expectation
DOI: 10.1063/PT.5.028267
New Scientist : Galaxies frequently collide and merge. Simulations of the collisions suggest that the outcome should be elliptical galaxies . However, most visible galaxies are disk shaped, either lenticular or spiral . Now, observations by Junko Ueda of the Japan Society for the Promotion of Science and her colleagues show that galaxy collisions may indeed produce disk-shaped galaxies. Using the Atacama Large Millimeter/Submillimeter Array (ALMA) radio telescope, they measured the movement of carbon monoxide gas in 37 merging galaxies. Of those, 30 showed signs of rotation around a central axis, which suggests they will eventually become disk shaped when the mergers are complete.
