More Images of GOODS Chandra Deep Field-South
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Chandra X-ray Images of GOODS CDFS
The image on the left shows a "stacked" Chandra image of
distant, massive galaxies detected with Spitzer. Image
stacking is a procedure used to detect emission from objects that is too
faint to be detected in single images. To enhance the signal, images of
these faint objects are stacked on top of one another. In this image, low-energy X-rays are shown in orange and high-energy X-rays
in blue, and the stacked object is in the center of the image (the other
sources beyond the center of the image are individual AGN that were
directly detected and are not part of the source stacking). The blue
stacked source confirms the hypothesis that large numbers of these young,
massive galaxies contain heavily obscured AGN. Spitzer also detected infrared emission from young, massive galaxies that
is consistent with expectations for star formation. These galaxies do not
contain AGN, because their supermassive black holes are dormant. A stacked
Chandra image (right) of these "normal" massive galaxies shows mainly soft X-ray
emission at the center, as expected.
(Credit: NASA/CXC/Durham/D.Alexander et al.)
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Artist's Illustration
The artist's illustration shows a typical massive galaxy as it
would have appeared when the universe was only about a quarter of its
current age. This young galaxy contains an active galactic nucleus (AGN), or quasar, in its center, a luminous object powered by the rapid growth of a
supermassive black hole. Some of the light from the AGN is obscured by dense
gas and dust near the center of the galaxy. The galaxy itself is
undergoing a growth spurt, as shown by bright regions of star formation in
the spiral arms.
(Credit: NASA/JPL-Caltech/T.Pyle (SSC))
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Spitzer Infrared Image of GOODS CDFS
This image, taken with Spitzer's infrared vision, shows a fraction of these black holes, which are located deep in the bellies of distant,
massive galaxies. Spitzer originally scanned the field of galaxies
shown in the picture as part of a multiwavelength program called the Great Observatories Origins Deep Survey, or Goods. This picture shows a portion of the Goods field called Goods-South. When astronomers saw the Spitzer data, they were surprised to find that hundreds of the galaxies between 9 and 11 billion light years away were shining with an unexpected excess of infrared light. They then followed up with X-ray data from Chandra of the same field, and applied a technique called stacking, which adds up the faint light of multiple galaxies. The results revealed that the infrared-bright galaxies are hiding many black holes that had been theorized about before but never seen. This excess infrared light is being produced by the growing black holes.
(Credit: NASA/JPL-Caltech/CEA/E.Daddi)
Return to GOODS Chandra Deep Field-South (October 25, 2007)