Centaurus A

Centaurus A or NGC 5128 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) and distance (10–16 million light-years). NGC 5128 is one of the closest radio galaxies to Earth, so its active galactic nucleus has been extensively studied by professional astronomers. The galaxy is also the fifth-brightest in the sky, making it an ideal amateur astronomy target, although the galaxy is only visible from low northern latitudes and the southern hemisphere.Centaurus A taken by SPECULOOS project.Centaurus A haloThe radio galaxy Centaurus A, as seen by ALMAImage taken by the Wide Field Imager attached to the MPG/ESO 2.2-meter telescope at the La Silla Observatory'Hubble's panchromatic vision... reveals the vibrant glow of young, blue star clusters...'A Hubble Space Telescope (HST) image of the dust disk in front of the nucleus of Centaurus A. Credit: HST/NASA/ESAThis image of the central parts of Centaurus A reveals the parallelogram-shaped remains of a smaller galaxy that was absorbed about 200 to 700 million years ago.The heavily obscured inner (barred?) spiral disk at 24 μm as shown by the Spitzer IR telescopeChandra X-ray view of Cen A in X-rays showing one relativistic jet from the central black holeA composite image showing the size of the radio glow from the galaxy Centaurus A in comparison to the full Moon'False-colour image of Centaurus A, showing radio (red), 24-micrometre infrared (green) and 0.5–5 keV X-ray emission (blue)Central part of the galaxyVideo about Centaurus A jets Centaurus A or NGC 5128 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) and distance (10–16 million light-years). NGC 5128 is one of the closest radio galaxies to Earth, so its active galactic nucleus has been extensively studied by professional astronomers. The galaxy is also the fifth-brightest in the sky, making it an ideal amateur astronomy target, although the galaxy is only visible from low northern latitudes and the southern hemisphere. The center of the galaxy contains a supermassive black hole with a mass equivalent to 55 million solar masses, 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. Like other starburst galaxies, a collision is suspected to be responsible for the intense burst of star formation. Models have suggested that Centaurus A was a large elliptical galaxy that collided and merged with a smaller spiral galaxy. NGC 5128 was discovered on 29 April 1826 by James Dunlop during a survey at the Parramatta Observatory. In 1847 John Herschel described the galaxy as 'two semi-ovals of elliptically formed nebula appearing to be cut asunder and separated by a broad obscure band parallel to the larger axis of the nebula, in the midst of which a faint streak of light parallel to the sides of the cut appears.' In 1949 John Gatenby Bolton, Bruce Slee and Gordon Stanley localized NGC 5128 as one of the first extragalactical radio sources. Five years later, Walter Baade and Rudolph Minkowski suggested that the peculiar structure is the result of a merge event of a giant elliptical galaxy and a small spiral galaxy. The first detection of X-ray emissions, using a sounding rocket, was performed in 1970. In 1975–76 gamma-ray emissions from Centaurus A were observed through the atmospheric Cerenkov technique. The Einstein Observatory detected an X-ray jet emanating from the nucleus in 1979. Ten years later, young blue stars were found along the central dust band with the Hubble Space Telescope. The Chandra X-ray Observatory identified in 1999 more than 200 new point sources. Another space telescope, the Spitzer Space Telescope, found a parallelogram-shaped structure of dust in near infrared images of Centaurus A in 2006. Evidence of gamma emissions with very high energy (more than 100 GeV) was detcted by the H.E.S.S-Observatorium in Namibia in 2009.