SCORES of missing galaxies are turning up in infrared images of the distant, early universe taken by NASA's Spitzer Space Telescope.
The early universe should be teeming with "active galactic nuclei" or AGNs. These are galaxies in the earliest stages of formation that emit X-rays because of the dust and gas pouring onto their central black holes. Yet astronomers see only a quarter of the AGNs they predict in the early universe, given the number around today.
Spitzer, launched in 2003, can see the missing youngsters by the infrared light they emit, rather than their X-rays, say two groups in papers submitted to
One group, led by Meg Urry of Yale University, says the sightings confirm something they've been claiming for years - that it is hard to see many distant AGNs simply because their X-rays are absorbed by dust around them.
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