Astronomy Picture of the Day
Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.
2003 July 5 
Posted on 07/04/2003 10:36:16 PM PDT by petuniasevan
Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.
2003 July 5
Explanation: Its core hidden from optical view by a thick lane of dust, the giant elliptical galaxy Centaurus A was among the first objects observed by the orbiting Chandra X-ray Observatory. Astronomers were not disappointed, as Centaurus A's appearance in x-rays makes its classification as an active galaxy easy to appreciate. Perhaps the most striking feature of this Chandra false-color x-ray view is the jet, 30,000 light-years long. Blasting toward the upper left corner of the picture, the jet seems to arise from the galaxy's bright central x-ray source -- suspected of harboring a black hole with a million or so times the mass of the Sun. Centaurus A is also seen to be teeming with other individual x-ray sources and a pervasive, diffuse x-ray glow. Most of these individual sources are likely to be neutron stars or solar mass black holes accreting material from their less exotic binary companion stars. The diffuse high-energy glow represents gas throughout the galaxy heated to temperatures of millions of degrees C. At 11 million light-years distant in the constellation Centaurus, Centaurus A (NGC 5128) is the closest active galaxy.
That's too far south for the northern half of the USA. If you're in southern Florida or south Texas, or Hawaii, look for it low in the southern sky on spring and early summer nights. In Miami, for instance, it would be about 20 degrees above the southern horizon at its midnight culmination on May 3rd. July 5th you'd have to look for it as soon as it gets dark. It will be in the south-southwest sky then and sets by midnight.
Chandra X-ray image of the jet:
Infrared ISO image with radio lobes superimposed:
This visible-light image from Cerro Tololo Observatory has been processed to bring out detail.
Composite image in X-rays, radio continuum, radio 21-centimeter band, and visible light. Spectacular!
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