ESO 146-5 (ESO 146-IG 005) is the designation given to a giant interacting

elliptical galaxy An elliptical galaxy is a type of galaxy with an approximately ellipsoidal shape and a smooth, nearly featureless image. They are one of the three main galaxy morphological classification, classes of galaxy described by Edwin Hubble in his Hub ...

in the center of the Abell 3827 cluster. It is well noted due to its strong

gravitational lensing A gravitational lens is matter, such as a galaxy cluster, cluster of galaxies or a point particle, that bends light from a distant source as it travels toward an observer. The amount of gravitational lensing is described by Albert Einstein's Ge ...

effect, measurements of which show the galaxy to be one of the most massive in the known universe.

Physical characteristics

This interacting galaxy was found 1.4 billion

light year A light-year, alternatively spelled light year (ly or lyr), is a unit of length used to express astronomical distance, astronomical distances and is equal to exactly , which is approximately 9.46 trillion km or 5.88 trillion mi. As defined by t ...

s away in the center of Abell 3827. A huge halo of stars is surrounding its interacting nuclei. It has immense gravity that holds the cluster together due to its mass. Its unusual shape has led to the conclusion that each one of the nuclei was formed from multiple collisions of smaller galaxies, and now the nuclei are merging to form a single huge elliptical galaxy.

Gravitational lensing A gravitational lens is matter, such as a galaxy cluster, cluster of galaxies or a point particle, that bends light from a distant source as it travels toward an observer. The amount of gravitational lensing is described by Albert Einstein's Ge ...

calculations appeared to show that there is a large

dark matter In astronomy, dark matter is an invisible and hypothetical form of matter that does not interact with light or other electromagnetic radiation. Dark matter is implied by gravity, gravitational effects that cannot be explained by general relat ...

mass lagging the top left nucleus, possibly explained by it being

self-interacting dark matter In astrophysics and particle physics, self-interacting dark matter (SIDM) is an alternative class of dark matter particles which have strong interactions, in contrast to the standard cold dark matter model (CDM). SIDM was postulated in 2000 as a s ...

. commentar
The Possible First Signs of Self-interacting Dark Matter
/ref> However, this finding has since been discounted based on further observations and modelling of the cluster.

Mass

Observations from the Gemini South Telescope has shown that ESO 146-5 has gravitationally lensed two galaxies, a galaxy 2.7 billion light years away, and the other, 5.1 billion light years away. Using Einstein's theory of

general relativity General relativity, also known as the general theory of relativity, and as Einstein's theory of gravity, is the differential geometry, geometric theory of gravitation published by Albert Einstein in 1915 and is the current description of grav ...

, it was measured to be approximately 27 ± 4 trillion

solar mass The solar mass () is a frequently used unit of mass in astronomy, equal to approximately . It is approximately equal to the mass of the Sun. It is often used to indicate the masses of other stars, as well as stellar clusters, nebulae, galaxie ...

es, making it one of the most massive galaxies in the known universe.

Gallery

File:Our_Giant_Universe.jpg, This detailed image features

Abell 3827 ESO 146-5 (ESO 146-IG 005) is the designation given to a giant interacting elliptical galaxy in the center of the Abell 3827 cluster. It is well noted due to its strong gravitational lensing effect, measurements of which show the galaxy to be o ...

Physical characteristics

Mass

Gallery

References

Further reading