Local Group of Galaxies


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Local Group of Galaxies

 

the group of nearest galaxies, the distances to which do not exceed 1 million parsecs (about 3 million light-years). It consists of two large groups with dwarf galaxies scattered between them—a total of about 30 members. Our galaxy and the nearby Magellanic Clouds dominate the first group in terms of size, mass, and intensity of light. A spiral galaxy—the Andromeda Nebula—which is still more powerful, occupies a central place in the second group. A smaller spiral galaxy—M 33 in Triangulum—two small elliptical galaxies, and several dwarf galaxies are located nearby. The dwarf galaxies, the smaller ones sometimes being called intergalactic star clusters, are divided into irregular and spheroidal galaxies, or Sculptor-system galaxies (after the constellation in which such a galaxy was first discovered). Apparently, the dimensions and intensity of light of galaxies do not have any lower limit, so that galaxies may be extremely faint.

Faint dwarf galaxies undoubtedly constitute the greater part of objects in the universe, but they cannot be observed at great distances. It may therefore be that the local group is not an isolated dense formation but only that part of the metagalaxy that surrounds us and whose population has been most completely clarified. Galaxies that are part of the local group are accessible to the most detailed study owing to their proximity to us.

B. A. VORONTSOV-VEL’IAMINOV

References in periodicals archive ?
This study also clarifies the role of the Great Attractor, a gravitational focal point in intergalactic space that influences the motion of our Local Group of galaxies and other galaxy clusters.
The nebula is one of the most active star-forming regions among the so-called Local Group of galaxies and is host to some of the most massive stars in the universe.
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The Milky Way and the Local Group of galaxies, it turns out, are not only being pulled by the dense regions in their extragalactic neighborhood, they are also being pushed by a previously undetected "void" that is largely devoid of galaxies.
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Shapley also anticipated that There may be several others in the local group of galaxies; such objects may be of frequent occurrence in intergalactic space and of much significance both in the census and the genealogy of [galaxies].
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Three years ago, Lauer and Marc Postman of the Space Telescope Science Institute in Baltimore set out to examine in greater detail the notion that a Great Attractor or some other concentration of mass was tugging on galaxies in the so-called local group of galaxies, which includes the Milky Way.
Maybe quasars don't lie at such great distances after all, they suggested; maybe quasars are more-or-less local, say in the Local Group of galaxies.
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