Stars born in early Universe conditions
Scientists have found a new window into the early days of the universe. Using the Galaxy Evolution Explorer (GALEX) telescope, a team of researchers, led by David Thilker of the Hopkins Physics Department, have found galaxy formation under conditions similar to the primordial universe.
"Using NASA's Galaxy Evolution Explorer, an ultraviolet space-telescope, we discovered an unexpected, quite unusual, type of dwarf galaxy forming in the local universe. The galaxies we found are odd, because they've managed to condense from pristine gas without the help of a dark matter halo and because they are doing this right now," Thilker said.
"The new objects are located inside the Leo Ring, a 600,000+ light-year wide gas cloud of hydrogen and helium that encircles a few massive galaxies in a galaxy group about 30 million light-years from us. This Ring is probably the best candidate of a primordial leftover from the early days of the universe," he added.
GALEX is a space-based satellite operated by Caltech for NASA. Launched in 2003, the telescope's goal is to observe changes in galaxies to help scientists understand how they are formed and evolve.
Barry Madore, an astrophysicist at the Carnegie Institution based in Pasadena, Calif., is one of the principal investigators for the GALEX project. "The primary result is that there is ongoing star formation in a distant ring of neutral hydrogen gas (the Leo Ring) that was previously thought to be devoid of all activity. The GALEX satellite is very sensitive to ultraviolet radiation, as given off by hot, young stars. We detected groups of stars in the Ring, thereby proving that it was indeed actively producing stars, but at a very low rate, such that all previous studies were incapable of detecting it," Madore said.
"If the Leo Ring is a very old structure (because of its size and location), then it is possible that it is composed of primordial gas, i.e. gas that has never been polluted by previous generations of stars (and supernovae, etc.). This would set up a situation where we are now viewing star formation taking place in gas that is more like the environment found in the very early Universe," he added.
"Using NASA's Galaxy Evolution Explorer, an ultraviolet space-telescope, we discovered an unexpected, quite unusual, type of dwarf galaxy forming in the local universe. The galaxies we found are odd, because they've managed to condense from pristine gas without the help of a dark matter halo and because they are doing this right now," Thilker said.
"The new objects are located inside the Leo Ring, a 600,000+ light-year wide gas cloud of hydrogen and helium that encircles a few massive galaxies in a galaxy group about 30 million light-years from us. This Ring is probably the best candidate of a primordial leftover from the early days of the universe," he added.
GALEX is a space-based satellite operated by Caltech for NASA. Launched in 2003, the telescope's goal is to observe changes in galaxies to help scientists understand how they are formed and evolve.
Barry Madore, an astrophysicist at the Carnegie Institution based in Pasadena, Calif., is one of the principal investigators for the GALEX project. "The primary result is that there is ongoing star formation in a distant ring of neutral hydrogen gas (the Leo Ring) that was previously thought to be devoid of all activity. The GALEX satellite is very sensitive to ultraviolet radiation, as given off by hot, young stars. We detected groups of stars in the Ring, thereby proving that it was indeed actively producing stars, but at a very low rate, such that all previous studies were incapable of detecting it," Madore said.
"If the Leo Ring is a very old structure (because of its size and location), then it is possible that it is composed of primordial gas, i.e. gas that has never been polluted by previous generations of stars (and supernovae, etc.). This would set up a situation where we are now viewing star formation taking place in gas that is more like the environment found in the very early Universe," he added.
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