Scientists have long theorized the existence of universe's first generation of stars. Also known as Population III stars, these celestial objects were formed out of the ancient remnants of the Big Bang and are believed to have formed out of helium, hydrogen and lithium, the only elements that existed prior to the appearance of subsequent stars.

Now, astronomers have discovered what to date is the brightest galaxy found in the early universe and even found evidence that it harbors the first generation of stars within it.

David Sobra, from the University of Lisbon in Portugal, and colleagues discovered the pocket of stars in an ancient galaxy called CR7, which they identified while using the Very Large Telescope of the European Southern Observatory in Chile and the W.M. Keck Observatory in Hawaii to peer back to early universe in a period known as reionization, which is about 800 million years after the Big Bang.

The astronomers were searching for distant galaxies when they found the 13.7 billion year-old CR7, the most luminous galaxy to be found to date and that it had the hallmarks of the earliest stars of the universe.  Their findings were published in The Astrophysical Journal on June 4.

"We may be witnessing, for the first time, direct evidence for the occurrence of waves of PopIII-like star formation which could happen from an original star cluster outwards (resulting from strong feedback which can delay PopIII star formation)," the researchers reported.

Calculations suggest that these ancients stars could be up to thousands of times more massive than the solar system's sun and would have burned quickly and brightly. The explosions of these stars would have scattered the elements these created into space. Subsequent generation of stars formed from these remnants and forged the cosmos with heavier elements like carbon, iron and oxygen.

Using the W. M. Keck Observatory telescopes, the researchers performed detailed spectroscopic observation of the galaxy and their observations revealed how far away the galaxy is from us and the intrinsic brightness of the stars that lurk within it.

"We confirmed that the galaxy is more than 12 billion light years from us," said study researcher Bahram Mobasher, from University of California, Riverside.  "Combining these with other observations, the UCR team successfully identified the presence of ions from elements that could only be produced through intense radiation."

Photo: ESO/M. Kornmesser 

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