Protogalaxy Spectra (IMAGE)
Caption
Hydrogen atoms in distant galaxies and in the intergalactic medium absorb or release photons of light at specific wavelengths producing characteristic absorption or emission lines when the light is dispersed into a spectrum. These are spectra of likely protogalaxies seen when the universe was at 15 percent of its present age. They show the Lyman alpha emission line region characteristic of a population of low mass, weakly star-forming galaxies commonly believed to be the building blocks of bright present day galaxies. Michael Rauch, George Becker and colleagues found these objects, which are about 10 times fainter than any galaxies ever seen in ground-based observations.
Credit
Michael Rauch, Carnegie Observatories
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