Chandra spies spectacular jet in nearby elliptical galaxy
CHANDRA X-RAY OBSERVATORY CENTER NEWS RELEASE
Posted: August 8, 2001

NASA's Chandra X-ray Observatory has captured a stunning image of Centaurus A, a massive elliptical galaxy approximately 11 million light years from Earth. In addition to the bright central source, a suspected supermassive black hole, and the X-ray jet emanating from the core, more than 200 point-like X-ray sources were identified and studied.

Centaurus A
This Chandra image of Cen A shows a bright central source: the Active Galactic Nucleus (AGN) suspected of harboring a supermassive black hole. Chandra also detects a jet emanating from the core and numerous point-like X-ray sources, all bathed in diffuse X-rays produced by several-million-degree gas that fills the galaxy. Photo: NASA/SAO/R.Kraft et al.
 
Because of their distribution around the center of the galaxy, it is believed that most of these sources are X-ray binaries in which a neutron star or stellar-sized black hole is accreting matter from a nearby companion star. A few may be supernova remnants or unrelated, more distant background galaxies.

Comparison of Cen A's X-ray binary population with populations in other galaxies is important for understanding the evolutionary history of galaxies. It is becoming clear that there are significant variations in the X-ray binary populations of otherwise similar galaxies. The reason for this is uncertain, but may be related to differences in the star formation history or mechanisms for the creation of X-ray binaries.

The observation of the jet has provided scientists some surprises as well. The X-ray structure of the jet has been shown to be significantly different than the radio structure, and the X-ray jet is much more uneven than originally believed. These results have cast doubts on simple models of how the energetic particles ejected from the active nucleus travel along the jet.

A team of scientists, led by Ralph Kraft of the Smithsonian Astrophysical Observatory, has begun to study each of these components of X-ray emission from Cen A. The unprecedented imaging resolution of Chandra allows scientists for the first time to clearly resolve each of these distinct components of the X-ray emission for detailed study.

This latest image of Centaurus A was the result of approximately 20 hours of observations with Chandra's Advanced CCD Imaging Spectrometer on December 5, 1999, and May 17, 2000.

First observed by Chandra in September 1999, Centaurus A was an early demonstration of the spectacular science this powerful X-ray observatory could do. Astronomers continue to use Chandra to study this elliptical galaxy (also known as NGC 5128) that contains a spectacular jet and a core teeming with X-ray emitting sources.

Optical
Optical image of Centaurus A. Photo: NASA/GSFC/SkyView