M31 made meals of other galaxies intwo phases

[old_eyes]

Article from New Scientist https://www.newscientist.com/article/2218628-andromeda-galaxy-ate-several-dwarf-galaxies-in-two-course-lunch/

analysis of globular clusters left over from galaxies absorbed by M31 shows two distinct populations. One with a lot of retained structure from the original galaxy and orbiting one way around M31 - indicating a more recent interaction - the other with less retained structure orbiting the other way round - evidence of a separate earlier event.