A panoramic survey of the region around our nearest galactic neighbour, the M31 Andromeda galaxy, has detected stars and coherent structures that are almost certainly remnants of dwarf galaxies destroyed by M31s tidal field. The brightest companion, the Triangulum galaxy (M33), is surrounded by a previously unknown prominent stellar structure that provides evidence for a recent encounter with M31. This new view of galactic structures is consistent with hierarchical cosmological models in which galaxies grow in mass by the accretion of smaller ones.
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