Multiple quasar
Encyclopedia
When two quasars
are so nearly in the same direction as seen from Earth that they appear to be a single quasar but may be separated by the use of telescopes, they are referred to as a 'double quasar'. These are two different quasars, and not the same quasar that is gravitationally lensed. This configuration is similar to the optical double star
.
Two quasars, a 'quasar pair', may be closely related in time and space, and be gravitationally bound to one another. These may take the form of two quasars in the same galaxy cluster
. This configuration is similar to two prominent stars in a star cluster
. A 'binary quasar', may be closely linked gravitationally and form a pair of interacting galaxies. This configuration is similar to that of a binary star
system.
Quasar
A quasi-stellar radio source is a very energetic and distant active galactic nucleus. Quasars are extremely luminous and were first identified as being high redshift sources of electromagnetic energy, including radio waves and visible light, that were point-like, similar to stars, rather than...
are so nearly in the same direction as seen from Earth that they appear to be a single quasar but may be separated by the use of telescopes, they are referred to as a 'double quasar'. These are two different quasars, and not the same quasar that is gravitationally lensed. This configuration is similar to the optical double star
Double star
In observational astronomy, a double star is a pair of stars that appear close to each other in the sky as seen from Earth when viewed through an optical telescope. This can happen either because the pair forms a binary star, i.e...
.
Two quasars, a 'quasar pair', may be closely related in time and space, and be gravitationally bound to one another. These may take the form of two quasars in the same galaxy cluster
Galaxy cluster
A galaxy cluster is a compact cluster of galaxies. Basic difference between a galaxy group and a galaxy cluster is that there are many more galaxies in a cluster than in a group. Also, galaxies in a cluster are more compact and have higher velocity dispersion. One of the key features of cluster is...
. This configuration is similar to two prominent stars in a star cluster
Star cluster
Star clusters or star clouds are groups of stars. Two types of star clusters can be distinguished: globular clusters are tight groups of hundreds of thousands of very old stars which are gravitationally bound, while open clusters, more loosely clustered groups of stars, generally contain less than...
. A 'binary quasar', may be closely linked gravitationally and form a pair of interacting galaxies. This configuration is similar to that of a binary star
Binary star
A binary star is a star system consisting of two stars orbiting around their common center of mass. The brighter star is called the primary and the other is its companion star, comes, or secondary...
system.
See also
- Einstein ringEinstein ringIn observational astronomy an Einstein ring is the deformation of the light from a source into a ring through gravitational lensing of the source's light by an object with an extremely large mass . This occurs when the source, lens and observer are all aligned...
- List of multiply imaged quasars
- Multiply imaged quasarMultiply imaged quasarA multiply imaged quasar is a quasar that is undergoing gravitational microlensing, resulting in double, triple or quadruple images of the same quasar...