SCORES of missing galaxies are turning up in infrared images of the distant, early universe taken by NASA鈥檚 Spitzer Space Telescope.
The early universe should be teeming with 鈥渁ctive galactic nuclei鈥� 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 The Astrophysical Journal and Astrophysical Journal Letters.
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One group, led by Meg Urry of Yale University, says the sightings confirm something they鈥檝e been claiming for years 鈥� that it is hard to see many distant AGNs simply because their X-rays are absorbed by dust around them.
Others had disagreed, saying that because we hadn鈥檛 seen them they couldn鈥檛 exist. But that controversy should now be laid to rest.