Peculiar galaxy
Encyclopedia
A peculiar galaxy is a galaxy
which is unusual in its size, shape, or composition. Peculiar galaxies come about as a result of interactions between galaxies, and they may contain atypical amounts of dust or gas, may have higher or lower surface brightness than a typical galaxy, or may have features such as nuclear jet
s. They can be highly irregular in shape due to the immense gravitational forces which act on them during encounters with other galaxies. Peculiar galaxies are designated by "p" or "pec" in some catalogs.
Galaxy
A galaxy is a massive, gravitationally bound system that consists of stars and stellar remnants, an interstellar medium of gas and dust, and an important but poorly understood component tentatively dubbed dark matter. The word galaxy is derived from the Greek galaxias , literally "milky", a...
which is unusual in its size, shape, or composition. Peculiar galaxies come about as a result of interactions between galaxies, and they may contain atypical amounts of dust or gas, may have higher or lower surface brightness than a typical galaxy, or may have features such as nuclear jet
Relativistic jet
Relativistic jets are extremely powerful jets of plasma which emerge from presumed massive objects at the centers of some active galaxies, notably radio galaxies and quasars. Their lengths can reach several thousand or even hundreds of thousands of light years...
s. They can be highly irregular in shape due to the immense gravitational forces which act on them during encounters with other galaxies. Peculiar galaxies are designated by "p" or "pec" in some catalogs.
See also
- Atlas of Peculiar GalaxiesAtlas of Peculiar GalaxiesThe Atlas of Peculiar Galaxies is a catalog of peculiar galaxies produced by Halton Arp. A total of 338 galaxies are presented in the atlas, which was originally published in 1966 by the California Institute of Technology....
- Irregular galaxyIrregular galaxyAn irregular galaxy is a galaxy that does not have a distinct regular shape, like a spiral or an elliptical galaxy. The shape of an irregular galaxy is uncommon – they do not fall into any of the regular classes of the Hubble sequence, and they are often chaotic in appearance, with neither a...
- Ring galaxyRing galaxyA ring galaxy is a galaxy with a ring-like appearance. The ring consists of massive, relatively young blue stars, which are extremely bright. The central region contains relatively little luminous matter. Some astronomers believe that ring galaxies are formed when a smaller galaxy passes through...
- Starburst galaxyStarburst galaxyA starburst galaxy is a galaxy in the process of an exceptionally high rate of star formation, compared to the usual star formation rate seen in most galaxies. Galaxies are often observed to have a burst of star formation after a collision or close encounter between two galaxies...