| Chandra
Deep Field - North |
November
1999 & February 2001 |
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Hubble Deep Field North (left) and Chandra Deep Field North (right)
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For
the first time, astronomers believe they have proof black holes of all sizes
once ruled the universe. NASA's Chandra X-ray Observatory provided the deepest
X-ray images ever recorded, and those pictures deliver a novel look at the
past 12 billion years of black holes. |
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| Image
Credit: NASA/PSU/G.Garmire,
N.Brandt, et al. |
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This
side-by-side presentation of the Hubble Deep Field-North (left) and the
Chandra Deep Field-North (right) clearly demonstrates the importance of
looking at the Universe in both the optical and X-ray regimes.
Twelve X-ray sources are detected in the HDF-N. The false colours represent
the "X-ray color" of the objects. Objects that appear more red
are cooler in the X-ray band, while objects that appear more blue are hotter
in the X-ray band. About half of the sources show strong evidence that the
X-rays are due to accretion onto supermassive black holes. |
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The
other sources have much lower luminosities, and in several cases are fairly
nearby. In these galaxies, the Chandra X-ray detection is most likely the
summed emission from a handful (or even one) bright sources within the galaxy,
such as stellar-size black holes in binary star systems, the hot gas within
the galaxy, or the remnants of supernova explosions.
Chandra is thus now peering far enough into the universe to detect the type
of X-ray emission that one finds in "normal" galaxies such as
the Milky Way. This allows us to look back several billion years to see
what our own galaxy and neighborhood (the Local Group) might have been like
at earlier times. |
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