Antennae Galaxies

Antennae Galaxies
NGC 4038 (left) and NGC 4039 (right)
Observation data (J2000 epoch)
Constellation Corvus[1]
Right ascension 12h 01m 53.0s / 12h 01m 53.6s[2]
Declination −18° 52′ 10″ / −18° 53′ 11″[2]
Redshift 1642 ± 12 / 1641 ± 9 km/s[2]
Distance 45 Mly / 65 Mly
Apparent magnitude (V) 11.2 / 11.1[2]
Characteristics
Type SB(s)m pec / SA(s)m pec[2]
Size 500,000 ly (150 kpc)[3][lower-alpha 1]
Apparent size (V) 5′.2 × 3′.1 / 3′.1 × 1′.6[2]
Notable features Interacting galaxies
Other designations
Ringtail Galaxy,[2] NGC 4038 / 4039,[2]
PGC 37967 / 37969, Arp 244,[2] Caldwell 60/61, UGCA 264/265[2]

The Antennae Galaxies, also known as NGC 4038/NGC 4039, are a pair of interacting galaxies in the constellation Corvus. 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 in 1785.[4]

General information

Ground-based visible light image of the Antennae Galaxies NGC 4038 and NGC 4039 by the Liverpool Telescope

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 stars, 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. Most galaxies probably undergo at least one significant collision in their lifetimes. This is likely the future of our Milky Way when it collides with the Andromeda Galaxy.

Five supernovae have been discovered in NGC 4038: SN 1921A, SN 1974E, SN 2004GT, SN 2007sr and SN 2013dk.[5]

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.[6]

They are located 0.25° north of 31 Crateris and 3.25° southwest of Gamma Corvi.[7]

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.[8] The young age of these clusters is in contrast to the average age of most known globular clusters, 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 and NGC 4039 was a spiral galaxy. Before the galaxies collided, NGC 4039 was larger than NGC 4038. 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 suggest that the Antennae Galaxies will eventually form an elliptical galaxy.[9]

X-ray source

Areas containing large amounts of neon, magnesium, and silicon were found when the Chandra X-ray Observatory analyzed the Antennae Galaxies. These elements are necessary in order for planets that may contain life to form. The clouds imaged contain 16 times as much magnesium and 24 times as much silicon as the Sun.

See also

References

  1. ↑ R. W. Sinnott, ed. (1988). The Complete New General Catalogue and Index Catalogue of Nebulae and Star Clusters by J. L. E. Dreyer. Sky Publishing Corporation and Cambridge University Press. ISBN 0-933346-51-4.
  2. 1 2 3 4 5 6 7 8 9 10 "NASA/IPAC Extragalactic Database". Results for NGC 4038 / 4039. Retrieved 2006-12-07.
  3. ↑ Astronomy Picture of the Day Archive (28 April 2017). "Exploring the Antennae". Retrieved 2018-05-01.
  4. ↑ "Corvus". Universe Today. Retrieved 2006-12-07.
  5. ↑ "List of Supernovae". IAU Central Bureau for Astronomical Telegrams. Retrieved 2015-08-22.
  6. ↑ "The Antennae Galaxies Found To Be Closer To Us". Space Daily. 2008-05-12. Retrieved 2008-06-30.
  7. ↑ O'Meara, Stephen James (2002). The Caldwell Objects. Cambridge University Press. pp. 240–43. ISBN 978-0-521-82796-6.
  8. ↑ Van Den Bergh, Sidney (2001). "van den Bergh, How Did Globular Clusters Form?". The Astrophysical Journal. 559 (2): L113. arXiv:astro-ph/0108298. Bibcode:2001ApJ...559L.113V. doi:10.1086/323754.
  9. ↑ J. E. Barnes; L. Hernquist (1992). "Dynamics of interacting galaxies". Annual Review of Astronomy and Astrophysics. 30 (1): 705–742. Bibcode:1992ARA&A..30..705B. doi:10.1146/annurev.aa.30.090192.003421.

Notes

  1. ↑ The quoted size was based on an assumed distance of 60 million ly although a more recent study gives a less remote distance of 45 million ly, giving consequently smaller values for the size.

Coordinates: 12h 01m 53s, −18° 52′ 10″

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