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GOODS unites extremely deep observations from NASA's
Great Observatories, the Spitzer Space Telescope,
Hubble, and
Chandra,
ESA's XMM-Newton,
and from the most powerful ground-based facilities,
to survey the distant universe to the faintest flux limits
across the broadest range of wavelengths. GOODS incorporates a
Spitzer Space Telescope
Legacy Program to carry out the deepest observations
with that facility at 3.6 to 24 microns, and a
Hubble Space Telescope Treasury Program for deep high-resolution
optical imaging. GOODS covers a total of roughly 320 square arcminutes
in two fields centered on the
Hubble Deep Field North and the
Chandra Deep Field South.
The space-based observations are
complemented by ground-based imaging and spectroscopy, including
an extensive commitment of ESO
and NOAO observing time.
Spitzer MIPS 24 micron image of the GOODS-South field,
with circles highlighting candidates for galaxies with "hidden"
supermassive black holes detected by their mid-infrared excess emission.
In work appearing in the Astrophysical Journal
(papers I and
II),
Daddi et al. 2007 investigate massive galaxies at redshifts near 2,
comparing their mid- and far-infrared, UV, radio, submm and X-ray emission to
study star formation and giant central black holes that power active galactic
nuclei. Many of the galaxies, particularly the most massive ones,
show excess 24 micron emission that suggests dust heating by an
active galactic nucleus. The galaxies are not individually detected
in the ultradeep Chandra X-ray data (normally a sure signature of
active nuclei), but X-ray stacking reveals a faint but highly
characteristic signature of obscured or `Compton-thick' active nuclei.
The observations unveil a large new population of previously hidden
black holes that were accreting mass at the same epoch as their host
galaxies were also rapidly building up their stars.
Spitzer Press Release and
Chandra Press Release.
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