Astronomers Detect First Stars 'Bubbling Out' From The Cosmic Dark Ages
Arthur T Knackerbracket has found the following story:
There was a period in the very early universe-known as the "cosmic dark ages"-when elementary particles, formed in the Big Bang, had combined to form neutral hydrogen but no stars or galaxies existed yet to light up the universe. This period began less than half a million years after the Big Bang and ended with the formation of the first stars. While this stage in the evolution of our universe is indicated by computer simulations, direct evidence is sparse.
Now, astronomers using the infrared imager NEWFIRM on the 4-meter Mayall Telescope at the Kitt Peak National Observatory of NSF's National Optical-Infrared Astronomy Research Laboratory (OIR Lab), have reported imaging a group of galaxies, known as EGS77, that contains these first stars. EGS, or the Extended Groth Strip, is a region imaged by HST in 2005; it corresponds to a narrow strip of the sky about the width of a finger held at arms length. There are at least 50,000 galaxies known within the strip. Their results were announced at a press conference held today at the 235th meeting of the American Astronomical Society (AAS) in Honolulu, Hawai'i.
[...] Once identified, the distances and hence the ages of these galaxies were confirmed with spectra taken with the MOSFIRE spectrograph at the Keck I telescope at the W. M. Keck Observatory on Maunakea in Hawai'i. All three galaxies show strong emission lines of hydrogen Lyman alpha at a redshift (z = 7.7), which means we are seeing them at about 680 million years after the Big Bang. The size of the ionized bubble around each was derived from computer modeling. These bubbles overlap spatially, but are large enough (about 2.2 million light-years) that Lyman alpha photons are redshifted before they reach the boundary of the bubble and can thus escape unscathed, allowing astronomers to detect them.
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