galaxy group
Sign in to saveAlso known as galactic group, small group of galaxies, mini-cluster of galaxies, small galactic group, sub-cluster of galaxies, group of galaxies
structure made up of a gravitationally-bound aggregation of about 50 or fewer galaxies; is smaller than a galaxy cluster
~4 min read
Encyclopedic overview
Four of the seven members of galaxy group HCG 16
A galaxy group or group of galaxies (GrG) is an aggregation of galaxies comprising about 50 or fewer gravitationally bound members, each at least as luminous as the Milky Way (about 10 times the luminosity of the Sun); collections of galaxies larger than groups that are first-order clustering are called galaxy clusters. The groups and clusters of galaxies can themselves be clustered, into superclusters of galaxies.
Excerpted from Wikipedia’s “galaxy group” article, available under the CC BY-SA 4.0 licence.