The Antennae Galaxies (also known as NGC 4038/NGC 4039 or Caldwell 60/Caldwell 61) are a pair of interacting galaxies in the

constellation A constellation is an area on the celestial sphere in which a group of visible stars forms Asterism (astronomy), a perceived pattern or outline, typically representing an animal, mythological subject, or inanimate object. The first constellati ...

Corvus ''Corvus'' is a widely distributed genus of passerine birds ranging from medium-sized to large-sized in the family Corvidae. It includes species commonly known as crows, ravens, and rooks. The species commonly encountered in Europe are the car ...

. They are currently going through a starburst phase, in which the collision of clouds of gas and dust, with entangled magnetic fields, causes rapid star formation. They were discovered by

William Herschel Frederick William Herschel ( ; ; 15 November 1738 – 25 August 1822) was a German-British astronomer and composer. He frequently collaborated with his younger sister and fellow astronomer Caroline Herschel. Born in the Electorate of Hanover ...

in 1785.

General information

Antennae Galaxies composite of ALMA and Hubble observations

The Antennae Galaxies are undergoing a galactic collision. These interacting galaxies are located 0.25° north of 31 Crateris and 3.25° southwest of Gamma Corvi. A 2008 study found that they are less remote from the Milky Way than previously thought—at 45 million light-years instead of 65 million light-years. Located in the NGC 4038 group with five other galaxies, these two galaxies are known as the Antennae Galaxies because the two long tails of

star A star is a luminous spheroid of plasma (physics), plasma held together by Self-gravitation, self-gravity. The List of nearest stars and brown dwarfs, nearest star to Earth is the Sun. Many other stars are visible to the naked eye at night sk ...

s, gas and dust ejected from the galaxies as a result of the collision resemble an insect's antennae. The nuclei of the two galaxies are joining to become one giant

galaxy A galaxy is a Physical system, system of stars, stellar remnants, interstellar medium, interstellar gas, cosmic dust, dust, and dark matter bound together by gravity. The word is derived from the Ancient Greek, Greek ' (), literally 'milky', ...

. Most galaxies probably undergo at least one significant collision in their lifetimes. This is likely the future of our

Milky Way The Milky Way or Milky Way Galaxy is the galaxy that includes the Solar System, with the name describing the #Appearance, galaxy's appearance from Earth: a hazy band of light seen in the night sky formed from stars in other arms of the galax ...

when it collides with the

Andromeda Galaxy The Andromeda Galaxy is a barred spiral galaxy and is the nearest major galaxy to the Milky Way. It was originally named the Andromeda Nebula and is cataloged as Messier 31, M31, and NGC 224. Andromeda has a Galaxy#Isophotal diameter, D25 isop ...

. This collision and merger sequence (the Toomre sequence) for galaxy evolution was developed in part by successfully modeling the Antennae Galaxies' "antennae" in particular. The Antennae galaxies also contain a relatively young collection of massive globular clusters that were possibly formed as a result of the collision between the two galaxies. The young age of these clusters is in contrast to the average age of most known globular clusters (which are around 12 billion years old), with the formation of the globulars likely originating from shockwaves, generated by the collision of the galaxies, compressing large, massive molecular clouds. The densest regions of the collapsing and compressing clouds are believed to be the birthplace of the clusters. NGC 4038 has a lot of Cepheid Variables, around 53 of them.

Supernovae

Four

supernova A supernova (: supernovae or supernovas) is a powerful and luminous explosion of a star. A supernova occurs during the last stellar evolution, evolutionary stages of a massive star, or when a white dwarf is triggered into runaway nuclear fusion ...

e have been observed in NGC 4038. * SN 1974E (type unknown, mag. 14) was discovered by Miklós Lovas on 21 March 1974. * SN 2004gt ( type Ic, mag. 14.9) was discovered by Berto Monard on 12 December 2004. * SN 2007sr ( type Ia, mag. 12.9) was discovered by the

Catalina Sky Survey Catalina Sky Survey (CSS; obs. code: 703) is an astronomical survey to discover comets and asteroids. It is conducted at the Steward Observatory's Catalina Station, located near Tucson, Arizona, in the United States. CSS focuses on the searc ...

on 18 December 2007. * SN 2013dk (type Ic, mag. 15.8) was discovered by the CHASE Project (CHilean Automatic Supernovas sEarch) on 22 June 2013. One

has been found in NGC 4039. * SN 1921A (type unknown, mag. 16) was discovered by

Edwin Hubble Edwin Powell Hubble (November 20, 1889 – September 28, 1953) was an American astronomer. He played a crucial role in establishing the fields of extragalactic astronomy and observational cosmology. Hubble proved that many objects previously ...

and

John Charles Duncan John Charles Duncan (February 8, 1882 – September 10, 1967) was an American astronomer. His work spanned astronomy’s transition from a focus on observation and location measurement to astrophysics. He was well known for his basic college textb ...

in March 1921.

Timeline

About 1.2 billion years ago, the Antennae were two separate galaxies. NGC 4038 was a

barred spiral galaxy A barred spiral galaxy is a spiral galaxy with a central bar-shaped structure composed of stars. Bars are found in about two thirds of all spiral galaxies in the local universe, and generally affect both the motions of stars and interstellar gas ...

and NGC 4039 was a

spiral galaxy Spiral galaxies form a galaxy morphological classification, class of galaxy originally described by Edwin Hubble in his 1936 work ''The Realm of the Nebulae''

. 900 million years ago, the Antennae began to approach one another, looking similar to NGC 2207 and IC 2163. 600 million years ago, the Antennae passed through each other, looking like the Mice Galaxies. 300 million years ago, the Antennae's stars began to be released from both galaxies. Today the two streamers of ejected stars extend far beyond the original galaxies, resulting in the antennae shape. Within 400 million years, the Antennae's nuclei will collide and become a single core with stars, gas, and dust around it. Observations and simulations of colliding galaxies (e.g., by Alar Toomre) suggest that the Antennae Galaxies will eventually form an

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 ...

X-ray source

Areas containing large amounts of

neon Neon is a chemical element; it has symbol Ne and atomic number 10. It is the second noble gas in the periodic table. Neon is a colorless, odorless, inert monatomic gas under standard conditions, with approximately two-thirds the density of ...

(Ne),

magnesium Magnesium is a chemical element; it has Symbol (chemistry), symbol Mg and atomic number 12. It is a shiny gray metal having a low density, low melting point and high chemical reactivity. Like the other alkaline earth metals (group 2 ...

(Mg), and

silicon Silicon is a chemical element; it has symbol Si and atomic number 14. It is a hard, brittle crystalline solid with a blue-grey metallic lustre, and is a tetravalent metalloid (sometimes considered a non-metal) and semiconductor. It is a membe ...

(Si) were found when the

Chandra X-ray Observatory The Chandra X-ray Observatory (CXO), previously known as the Advanced X-ray Astrophysics Facility (AXAF), is a Flagship-class space telescope launched aboard the during STS-93 by NASA on July 23, 1999. Chandra is sensitive to X-ray sources ...

analyzed the Antennae Galaxies. Heavy elements such as these are necessary in order for planets that may contain

life Life, also known as biota, refers to matter that has biological processes, such as Cell signaling, signaling and self-sustaining processes. It is defined descriptively by the capacity for homeostasis, Structure#Biological, organisation, met ...

(as we know it) to form. The clouds imaged contain 16 times as much magnesium and 24 times as much silicon as the

Sun The Sun is the star at the centre of the Solar System. It is a massive, nearly perfect sphere of hot plasma, heated to incandescence by nuclear fusion reactions in its core, radiating the energy from its surface mainly as visible light a ...

References

Notes

External links

Astronomy Picture of the Day Astronomy is a natural science that studies celestial objects and the phenomena that occur in the cosmos. It uses mathematics, physics, and chemistry in order to explain their origin and their overall evolution. Objects of interest include ...

The Antennae Galaxies (10/22/1997)
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The Antennae (05/07/2010)
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The Antennae (04/29/2011)
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The Antennae (02/12/2015)The Register: Galactic prang fingered in star formation mysteryESA/Hubble images of Antennae Galaxies
* * ttp://www.constellation-guide.com/antennae-galaxies/ Antennae Galaxies at Constellation Guide {{Portal bar, Astronomy, Stars, Outer space Barred spiral galaxies Unbarred spiral galaxies Peculiar galaxies Interacting galaxies NGC 4038 Group Corvus (constellation) NGC objects 037967 244 060b Astronomical objects discovered in 1785 UGCA objects Galaxy mergers