Galaxy group

A group of galaxies is a smaller clusters of galaxies with less than 50 members in a volume with a diameter of up to 10 million light-years ( MLJ ). Their mass is about 1013 solar masses; the velocities of its members vary by about 150 km / s The demarcation of clusters of galaxies is not sharply defined.

Even our Milky Way system is in a group, the Local Group. Besides the Milky Way This includes the spiral galaxy M 31 in the constellation of Andromeda, M 33 in the constellation triangle as well as several companion galaxies such as the Magellanic Clouds.

Groups of galaxies in close proximity

In the vicinity of the Local Group, there are several other galaxy clusters that hold a large part of the brightest galaxies in the night sky as members. The most important of these groups are:

  • The Maffei group, named after the discoverer of the two largest galaxies in this group. This group is at a distance of six to twelve MLJ, from our point of almost completely obscured by the Milky Way disk. Although it is the nearest neighbor group (it was even a few years ago regarded as part of the Local Group ), it was not discovered until late in the twentieth century. The only brighter galaxy this group that does not appear extremely darkened by interstellar extinction, IC 342 The group is in the constellations of Cassiopeia and giraffe.
  • The Sculptor group, named after the constellation Sculptor, in which the brightest members of the group are. This group is about ten MLJ away and contains the Sculptor Galaxy (NGC 253), the brightest galaxy outside the Local Group, which can be seen in the southern hemisphere.
  • The M81 group, which continues as the Sculptor group is only slightly removed and with Bode's Galaxy (M 81 ) contains the brightest galaxy outside the Local Group.
  • The M83 or NGC 5128 group, which is named after the brightest member galaxies, the Southern Pinwheel Galaxy ( M83 ) and Centaurus A ( NGC 5128 ). The group is to find water snake and Centaur in the constellations of the southern sky and is 12 to 17 million light years away.
  • The Canes Venatici - I or M94 group in the constellation of hunting dogs. The group is 13 to 18 MLJ removed; their brightest member is the spiral galaxy M 94
  • Galaxy clusters
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