"Galaxy mergers" refers to the coming together of two or more galaxies in space. It's like when two or more large groups of stars, gas, and dust combine to create a bigger and more massive galaxy. Full definition
This result helps explain how galaxy mergers create the larger numbers of big star clusters seen in elliptical galaxies. (hubble25th.org)
We however do not yet know whether galaxy mergers are also responsible for these, or whether they are formed by cold gas gradually falling into the galaxy. (sciencedaily.com)
NGC 6240 is an important object to investigate in order to understand the physical and evolutional relationship among the processes of galaxy merger, the action of a starburst, and the phenomenon of an active galactic nucleus. (sciencedaily.com)