galactic cannibalism

astronomy

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June 29, 2026

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Galactic cannibalism refers to the process where a larger galaxy absorbs a smaller galaxy through gravitational attraction. This phenomenon is a significant aspect of galaxy evolution.1

Galaxies are not isolated entities; they often exist in groups or clusters, and interactions are common. In dense clusters, frequent collisions can strip interstellar gas from galaxies, transforming spiral galaxies into gasless systems or S0 galaxies.2

A notable example of galactic cannibalism is the formation of cD galaxies. These are massive galaxies found at the centers of some clusters that have captured and absorbed smaller galaxies. The outer structures and multiple nuclei of cD galaxies are believed to be remnants of these absorbed galaxies. Evidence of this process is also seen in our own Milky Way Galaxy, which has absorbed smaller galaxies like the Sagittarius Galaxy and the Canis Major Dwarf Galaxy.21

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Interactions between cluster members
…refer to this process as galactic cannibalism. In this sense, the outer extended disks of cD systems, as well as their multiple nuclei, represent the remains of past partly digested “meals.”
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…refer to this process as galactic cannibalism. In this sense, the outer extended disks of cD systems, as well as their multiple nuclei, represent the remains of past partly digested “meals.”
Read More