sábado, 26 de mayo de 2012

Super-Massive Galaxies of the Early Universe


Sensitive infrared cameras staring over large fields of view are the best way to find large numbers of very distant objects for analyses SAO astronomers Jia-Sheng Huang, Giovanni Fazio, and Matt Ashby, together with a team of colleagues, used the infrared camera on the Spitzer Space Telescope to undertake a very deep and sensitive search for distant infrared galaxies in an area of the sky one twentieth the size of the full moon.
They coordinated their study with infrared images from Hubble.The scientists discovered twenty five peculiar infrared objects in their field. Follow-up analyses revealed that between eleven and nineteen of them date to cosmic epochs from 1.5 to 3 billion years after the big bang.
These galaxies seem to be very massive and to contain significant amounts of warm dust. Two other sources just as massive seem to be even older, dating from a period only one billion years after the big bang. The latter present a serious challenge to current theories about galaxy evolution, which predict very few such objects should exist at such an early time.
The new survey is significant not only because it has discovered such distant galaxies, but also because it points to a previously unrecognized galaxy population whose properties are significantly different from those of known galaxies at similar epochs.
Source: The Daily Galaxy - cfa.harvard.edu

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