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.

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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.

Vera Rubin's universe: by looking at things others didn't think were interesting, the astronomer often labeled the "mother of dark matter" forever changed our picture of the cosmos

Some emissions occur when particles reaccelerate due to the collision of small groups of galaxies with the cluster.

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But if they turn up outside of clusters, isolated or with small groups of galaxies, then perhaps they're just born that way.

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Stephan O'Meara spotted a tight string of stars in an east-west direction almost halfway between these two compact groups of galaxies.

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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.

2 galaxy systems almost similar to the Milky Way found

Perhaps the most approachable of these was the Hickson Compact Groups of Galaxies (HCG) catalogue, (9) compiled by Paul Hickson in 1982.

Meeting of the Deep Sky Section, 2011 March 12 (Part II): held at Ashfordvillage Hall, Ashford Hill, Newbury, Berkshire

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.

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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.

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They consist of closely bound groups of galaxies, which are themselves made up of billions of stars.

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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.

The sky's the limit: this year marks the 400th anniversary of Galileo's telescope. See how astronomers' view of the night sky has changed since then

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 perception of the biosphere

This 79th entry in a catalogue of compact groups of galaxies was compiled in 1892 by Paul Hickson He completed his studies at the University of Alberta with honours in physics.