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

interacting galaxies Interacting galaxies (''colliding galaxies'') are galaxies whose gravitational fields result in a disturbance of one another. An example of a minor interaction is a satellite galaxy disturbing the primary galaxy's spiral arms. An example of a ...

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 origins of the e ...

Corvus ''Corvus'' is a widely distributed genus of medium-sized to large birds in the family Corvidae. It includes species commonly known as crows, ravens and Rook (bird), rooks. The species commonly encountered in Europe are the carrion crow, the hoo ...

. 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 (; german: Friedrich Wilhelm Herschel; 15 November 1738 – 25 August 1822) was a German-born British astronomer and composer. He frequently collaborated with his younger sister and fellow astronomer Caroline H ...

in 1785.

General information

Antennae Galaxies composite of ALMA and Hubble observations

The Antennae Galaxies are undergoing a galactic collision. 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 an astronomical object comprising a luminous spheroid of plasma (physics), plasma held together by its gravity. The List of nearest stars and brown dwarfs, nearest star to Earth is the Sun. Many other stars are visible to the naked ...

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 system of stars, stellar remnants, interstellar gas, dust, dark matter, bound together by gravity. The word is derived from the Greek ' (), literally 'milky', a reference to the Milky Way galaxy that contains the Solar System. ...

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

Milky Way The Milky Way is the galaxy that includes our Solar System, with the name describing the galaxy's appearance from Earth: a hazy band of light seen in the night sky formed from stars that cannot be individually distinguished by the naked eye ...

when it collides with the

Andromeda Galaxy The Andromeda Galaxy (IPA: ), also known as Messier 31, M31, or NGC 224 and originally the Andromeda Nebula, is a barred spiral galaxy with the diameter of about approximately from Earth and the nearest large galaxy to the Milky Way. The gala ...

. This collision and merger sequence (the Toomre sequence) for galaxy evolution was developed in part by successfully modeling the Antennae Galaxies' "antennae" in particular. Five supernovae have been discovered in NGC 4038: SN 1921A, SN 1974E, SN 2004GT,

SN 2007sr SN 2007sr was a Type Ia supernova A Type Ia supernova (read: "type one-A") is a type of supernova that occurs in binary systems (two stars orbiting one another) in which one of the stars is a white dwarf. The other star can be anything from a ...

and SN 2013dk. A recent study finds that these interacting galaxies are less remote from the Milky Way than previously thought—at 45 million light-years instead of 65 million light-years. They are located 0.25° north of 31 Crateris and 3.25° southwest of

Gamma Corvi Gamma Corvi (γ Corvi, abbreviated Gamma Crv, γ Crv) is a binary star and the brightest star in the southern constellation of Corvus, having an apparent visual magnitude of 2.59. The system's two components are designated Gamma Corvi A (of ...

. 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.

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, and generally affect both the motions of stars and interstellar gas within spiral galaxi ...

and NGC 4039 was a

spiral galaxy Spiral galaxies form a class of galaxy originally described by Edwin Hubble in his 1936 work ''The Realm of the Nebulae''NGC 2207 and IC 2163 __NOTOC__ NGC 2207 and IC 2163 are a pair of colliding spiral galaxies about 80 million light-years away in the constellation Canis Major. Both galaxies were discovered by John Herschel in 1835. The larger spiral, NGC 2207, is classified as an i ...

. 600 million years ago, the Antennae passed through each other, looking like the

Mice Galaxies NGC 4676, or the Mice Galaxies, are two spiral galaxies in the constellation Coma Berenices. About 290 million light-years distant, they have begun the process of colliding and merging. Their name refers to the long tails produced by tidal acti ...

. 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 Alar Toomre (born 5 February 1937, in Rakvere) is an American astronomer and mathematician. He is a professor of applied mathematics at the Massachusetts Institute of Technology. Toomre's research is focused on the dynamics of galaxies. He is a ...

) 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 four main classes of galaxy described by Edwin Hubble in his Hubble sequence and 1936 work ''The R ...

X-ray source

Areas containing large amounts of neon, magnesium, and silicon 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 1 ...

analyzed the Antennae Galaxies.

Heavy elements upright=1.2, Crystals of osmium, a heavy metal nearly twice as dense as lead">lead.html" ;"title="osmium, a heavy metal nearly twice as dense as lead">osmium, a heavy metal nearly twice as dense as lead Heavy metals are generally defined as ...

such as these are necessary in order for planets that may contain

life Life is a quality that distinguishes matter that has biological processes, such as signaling and self-sustaining processes, from that which does not, and is defined by the capacity for growth, reaction to stimuli, metabolism, energ ...

(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 center of the Solar System. It is a nearly perfect ball of hot plasma, heated to incandescence by nuclear fusion reactions in its core. The Sun radiates this energy mainly as light, ultraviolet, and infrared radi ...

References

Notes

External links

Astronomy Picture of the Day Astronomy Picture of the Day (APOD) is a website provided by NASA and Michigan Technological University (MTU). According to the website, "Each day a different image or photograph of our universe is featured, along with a brief explanation written ...

The Antennae Galaxies (10/22/1997)
*

The Antennae (05/07/2010)
*

The Antennae (04/29/2011)
*

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 __NOTOC__ Year 244 (Roman numerals, CCXLIV) was a leap year starting on Monday (link will display the full calendar) of the Julian calendar. At the time, it was known as the Year of the Consulship of Tiberius Pollenius Armenius Peregrinus, Arm ...