Centaurus A

Centaurus A, also known as NGC 5128, is a lenticular galaxy that is around 11 million light years from Earth. It is in the Centaurus constellation. It is one of the closest radio galaxies, so it has been studied extensively. It is the fifth brightest galaxy in the night sky. It is an easy study for amateur astronomers who are in the low northern latitudes and the southern hemisphere. Centaurus A is located approximately 4° north of Omega Centauri. The bright central bulge and dark dust lane are visible even in finderscopes and large binoculars and additional structure may be seen in larger telescopes.

The strong jets of plasma(relativistic jets) that are responsible for the galaxy’s emissions in the x-ray and radio wavelengths are believed to come from a super massive black hole at the center of the galaxy. Using the Spitzer Space Telescope, scientists have confirmed that Centaurus A is going through a galaxy collision and is currently devouring a spiral galaxy. The bulge of this galaxy is comprised mainly of evolved red stars. The dusty disk, however, has been the site of more recent star formation. More than 100 star formation regions have been identified in the disk.

A lenticular galaxy is a type of galaxy that is between an elliptical and a spiral galaxy. These galaxies are disc galaxies like spiral galaxies, but have used up or lost most of their interstellar matter and therefore have very little ongoing star formation. Because of this, they consist mainly of aging stars like elliptical galaxies. They combine some of the characteristics of both, but can not be confined to the definition of either.

This galaxy includes one supernova. The supernova, named SN 1986G, was discovered within the dark dust lane of the galaxy in 1986. It was later identified as a type Ia supernovae which forms when a white dwarf’s mass grows large enough to ignite carbon fusion in its center; thereby touching off a runaway thermonuclear reaction. SN 1986G was used to demonstrate that the spectra of type Ia supernovae are not all identical, and that type Ia supernovae may differ in the way that they change in brightness over time.

Try the NASA page about Centaurus A. Here on Universe Today we have a great article about the ring of stars in the galaxy’s dust ring. Astronomy Cast has a good episode about the importance of X-ray Astronomy.

Sources: NASA, Wikipedia, SEDS

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