groups of galaxies

groups of galaxies

Small isolated collections of from three to a hundred galaxies, examples being the Local Group and Stephan's Quintet. Most are gravitationally bound systems but a few may be due to chance line-of-sight projections. If the groups are bound and stable their mass-to-luminosity ratio must be high. The most extreme groups where several galaxies are in close proximity to each other are known as compact groups of galaxies. The members of such groups often show morphological features typical of interacting galaxies.
Collins Dictionary of Astronomy © Market House Books Ltd, 2006
References in periodicals archive ?
Her work may have inspired Rubin's thesis, which suggested groups of galaxies exhibited extra motion, in addition to their predictable motion due to the expanding universe.
Some emissions occur when particles reaccelerate due to the collision of small groups of galaxies with the cluster.
Examples are stellar clusters, external galaxies, and clusters and groups of galaxies. In those cases, the problem is analogous.
But if they turn up outside of clusters, isolated or with small groups of galaxies, then perhaps they're just born that way.
Stephan O'Meara spotted a tight string of stars in an east-west direction almost halfway between these two compact groups of galaxies. He characterized this handful of stars as "fleas" surrounding the group of deer!
Andrews in Scotland, searched for groups of galaxies similar to ours in the most detailed map of the local universe yet, the Galaxy and Mass Assembly (GAMA) survey.
Perhaps the most approachable of these was the Hickson Compact Groups of Galaxies (HCG) catalogue, (9) compiled by Paul Hickson in 1982.
From the formation of stars and planets to the behaviour of the largest groups of galaxies, Prof Ward-Thompson's work on Herschel has helped provide images of the universe in unprecedented detail.
From the formation of stars and planets, to the behaviour of the largest groups of galaxies, Herschel is providing images of the universe in unprecedented detail.
They consist of closely bound groups of galaxies, which are themselves made up of billions of stars.
Astronomers detect these groups of galaxies by looking for their shadows in the cosmic microwave background radiation, which astronomers think is what's left over from the Big Bang.
With the aid of powerful telescopes, such as those of Mount Palomar in California, or the orbiting Hubble telescope, we can already observe large stellar bodies that are great distances away such as galaxies or groups of galaxies. The Local Group is the name given to a group of 18 to 20 galaxies including the Milky Way, in which the Earth is situated.