Large-scale structure of the cosmos Reference Libraries

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Virgo Cluster
2010-09-16 15:18:29

The Virgo Cluster consists of galaxies at a distance of around 59 Mly away in the constellation Virgo. Containing between 1300 to 2000 galaxies the Virgo Cluster is the heart of the Local Supercluster. Its mass is estimated at 1.2 × 1015 M☉ out to 8 degrees of the cluster's center or a radius of about 2.2 Mpc. Most of the brighter galaxies in the cluster were discovered by Charles...

Magellanic Clouds
2010-09-16 15:14:03

The two Magellanic Clouds (or Nubeculae Magellani), composed of the Large Megellanic Cloud and the Small Magellanic Cloud, are irregular dwarf galaxies visible in the southern hemisphere. They are members of our Local Group and orbit the Milky Way galaxy. Persian astronomer Al Sufi, in 964, was the first to have written anything about the Magellanic Clouds proving they have been known since...

NGC 5866 Group
2010-09-16 15:00:46

The NGC 5866, located in the Draco constellation, is named after the galaxy with the highest magnitude however some catalogs list NGC 5907 as the brightest member. The M51 Group and the M101 Group are NGC 5866 closest neighbor. The distances between these groups are similar which suggest the three groups are part of a single large, loose, elongated group. However, most identification methods...

M101 Group
2010-09-13 17:13:25

The M101 Group, one of many in the Virgo Supercluster, is located in Ursa Major and named after the brightest galaxy in the group, the Pinwheel Galaxy (M101). The group is composed mostly of members that are companions of the Pinwheel Galaxy. The M51 Group and the NGC 5866 Group are M101's closest neighbor. The distances between these groups are similar which suggest the three groups are...

M81 Group
2010-09-13 17:09:55

The M81 Group, containing the well known galaxies Messier 81 and Messier 82, is a group of galaxies within the constellation Ursa Major. Along with Messier 81 and 82 are several other galaxies with apparent brightness. The center, located at an approximate distance of 3.6 Mpc, is one of the nearest groups to the Local Group. The total estimated mass of the group is (1.03 ± 0.17) ×...

The Local Group
2010-09-13 17:05:00

The Local Group, compromising more than 30 galaxies (including dwarf galaxies and the Milky Way), is a group of galaxies with a gravitational center located somewhere between the Milky Way and the Andromeda Galaxy. With a binary (dumbbell) shape and a total mass of (1.29 ± 0.14) × 1012M the Local group covers a 10 million light-year diameter. The local group is part of the Virgo...

IC 342
2010-09-13 16:59:36

The IC 342/Maffei Group (also known as the IC 342 Group or the Maffei 1 Group) is the closest group of galaxies to the Local Group. The member galaxies are both concentrated around the two brightest galaxies of IC 342 and Maffei 1. The group can therefore be described as a binary group. Along with many others the group is located in the Virgo Supercluster.

Coma Cluster
2010-09-13 16:56:08

The Coma Cluster (Abell 1656), along with the Leo Cluster, is one of two major clusters compromising the Coma Supercluster. It contains over 1000 identified galaxies. Most of the galaxies in the center of the Coma Cluster are elliptical galaxies including both dwarf and giant. However the center is dominated by NGC 4874 and NGC 4889, two giant elliptical galaxies. The brightest galaxies are...

Centaurus Cluster
2010-09-13 16:39:39

The Centaurus A/M83, divided into subgroup Cen A and M83, is a complex group of galaxies located within Hydra, Centaurus, and Virgo constellations. The Cen A Subgroup, at a distance of 11.9 Mly (3.66 Mpc), is centered around Centaurus A, a nearby radio galaxy. The M83 Subgroup, at a distance of 14.9 Mly (4.56 Mpc), is centered around the Messier 83 (M83), a face-on spiral galaxy. Due to the...

Sculptor Group
2010-09-13 16:24:54

At a distance of 3.9 Mpc from the Milky Way, the Sculptor Group is one of nearest groups of galaxies to the Local Gropu. Sculptor is made up of a loose group of galaxies near the south galactic pole. The Sculptor Galaxy (NGC 253) and a few other galaxies form a gravitationally-bound core in the center of this group, however, since they are only weakly bound the group may also be described...

Word of the Day
  • A goblin in English folklore, often appearing in the shape of a large dog and believed to portend imminent death or misfortune.
  • A ghost, wraith, hobgoblin, elf, or spirit.
The origin of 'barghest' is not known, but it may be from perhaps burh-ghest, town-ghost, or German Berg-geist (mountain spirit) or Bär-geist (bear-spirit).