The Andromeda galaxy’s most important merger about 2 billion years ago as M32’s likely progenitor

  title={The Andromeda galaxy’s most important merger about 2 billion years ago as M32’s likely progenitor},
  author={Richard D’Souza and Eric F. Bell},
  journal={Nature Astronomy},
Although the proximity of the Andromeda galaxy (M31) offers an opportunity to understand how mergers affect galaxies1, uncertainty remains about M31’s most important mergers. Previous studies focused individually on the giant stellar stream2 or the impact of M32 on M31’s disk3,4, thereby suggesting many substantial satellite interactions5. Yet models of M31’s disk heating6 and the similarity between the stellar populations of different tidal substructures in M31’s outskirts7 both suggested a… 

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