Centaurus A

For other uses, see Centaurus (disambiguation).
Centaurus A
Centaurus A (NGC 5128)
Observation data (J2000 epoch)
ConstellationCentaurus
Right ascension13h 25m 27.6s[1]
Declination−43° 01′ 09″[1]
Redshift547 ± 5 km/s[1]
Distance11–13 Mly (3–5 Mpc)[2][3][4][5][6]
Apparent magnitude (V)6.84[7][8]
Characteristics
TypeS0 pec[1] or Ep[9]
Size60,000 ly[10]
Apparent size (V)25'.7 × 20'.0[1]
Notable featuresClosest radio galaxy; closest BL Lacertae object; unusual dust lane
Other designations
NGC 5128,[1] Arp 153,[1] PGC 46957,[1] 4U 1322–42,[11] Caldwell 77

Centaurus A (also known as NGC 5128 or Caldwell 77) is a galaxy in the constellation of Centaurus. It was discovered in 1826 by Scottish astronomer James Dunlop from his home in Parramatta, in New South Wales, Australia. There is considerable debate in the literature regarding the galaxy's fundamental properties such as its Hubble type (lenticular galaxy or a giant elliptical galaxy)[9] and distance (11–13 million light-years).[2][3][4][5][6] It is the closest radio galaxy to Earth, as well as the closest BL Lac object,[12] so its active galactic nucleus has been extensively studied by professional astronomers.[13] The galaxy is also the fifth-brightest in the sky,[13] making it an ideal amateur astronomy target.[14] It is only visible from the southern hemisphere and low northern latitudes.

The center of the galaxy contains a supermassive black hole with a mass of 55 million solar masses,[15] which ejects a relativistic jet that is responsible for emissions in the X-ray and radio wavelengths. By taking radio observations of the jet separated by a decade, astronomers have determined that the inner parts of the jet are moving at about half of the speed of light. X-rays are produced farther out as the jet collides with surrounding gases, resulting in the creation of highly energetic particles. The X-ray jets of Centaurus A are thousands of light-years long, while the radio jets are over a million light-years long.[16]

It is also one of the nearest large starburst galaxies, of which a galactic collision is suspected to be responsible for an intense burst of star formation. Models have suggested that Centaurus A was a large elliptical galaxy that collided with a smaller spiral galaxy, with which it will eventually merge.[17] For that reason, the galaxy has been of particular interest to astronomers for years. While collisions of spiral galaxies are relatively common, the effects of a collision between an elliptical and a spiral galaxy are not fully understood.[18]

  1. ^ a b c d e f g h "NASA/IPAC Extragalactic Database". Results for Centaurus A. Retrieved 6 December 2006.
  2. ^ a b J. L. Tonry; A. Dressler; J. P. Blakeslee; E. A. Ajhar; et al. (2001). "The SBF Survey of Galaxy Distances. IV. SBF Magnitudes, Colors, and Distances". Astrophysical Journal. 546 (2): 681–693. arXiv:astro-ph/0011223. Bibcode:2001ApJ...546..681T. doi:10.1086/318301. S2CID 17628238.
  3. ^ a b "Distance Results for NGC 5128". NASA/IPAC Extragalactic Database. Retrieved 26 April 2010.
  4. ^ a b Cite error: The named reference ferrarese07 was invoked but never defined (see the help page).
  5. ^ a b Cite error: The named reference majaess10 was invoked but never defined (see the help page).
  6. ^ a b Cite error: The named reference harris10 was invoked but never defined (see the help page).
  7. ^ "NAME Centaurus A". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 29 November 2009.
  8. ^ Armando, Gil de Paz; Boissier; Madore; Seibert; Boselli; et al. (2007). "The GALEX Ultraviolet Atlas of Nearby Galaxies". Astrophysical Journal Supplement. 173 (2): 185–255. arXiv:astro-ph/0606440. Bibcode:2007ApJS..173..185G. doi:10.1086/516636. S2CID 119085482.
  9. ^ a b Cite error: The named reference harris10b was invoked but never defined (see the help page).
  10. ^ "APOD: 2012 April 4 – Centaurus A". apod.nasa.gov. Archived from the original on 3 October 2014.
  11. ^ "UHURU4 – Uhuru Fourth (4U) Catalog". heasarc.gsfc.nasa.gov.
  12. ^ Chiaberge, M.; Capetti, A.; Celotti, A. (2001). "The BL Lac heart of Centaurus A". Monthly Notices of the Royal Astronomical Society. 324 (4): L33–L37. arXiv:astro-ph/0105159. Bibcode:2001MNRAS.324L..33C. doi:10.1046/j.1365-8711.2001.04642.x.
  13. ^ a b F. P. Israel (1998). "Centaurus A – NGC 5128". Astronomy and Astrophysics Review. 8 (4): 237–278. arXiv:astro-ph/9811051. Bibcode:1998A&ARv...8..237I. doi:10.1007/s001590050011. S2CID 18353347.
  14. ^ D. J. Eicher (1988). The Universe from Your Backyard. Cambridge: Cambridge University Press. ISBN 978-0-521-36299-3.
  15. ^ "Radio Telescopes Capture Best-Ever Snapshot of Black Hole Jets". NASA. 20 May 2011. Retrieved 2 October 2012.
  16. ^ Nemiroff, R.; Bonnell, J., eds. (13 April 2011). "Centaurus Radio Jets Rising". Astronomy Picture of the Day. NASA. Retrieved 16 April 2011.
  17. ^ Quillen, A. C.; Brookes, M. H.; Keene, J.; Stern, D.; Lawrence, C. R.; Werner, M. W. (2006). "Spitzer Observations of the Dusty Warped Disk of Centaurus A". Astrophysical Journal. 645 (2): 1092–1101. arXiv:astro-ph/0601135. Bibcode:2006ApJ...645.1092Q. doi:10.1086/504418. S2CID 18443587.
  18. ^ "Radio galaxy Centaurus A". European Southern Observatory (ESO). 8 February 2000.