Researchers have found evidence of a small far off galaxy lurking in “dark ages” after detecting light from a star that exploded more than 12 billion light-years ago.
Around 12.7 billion years ago the star exploded, ripping itself apart and blasting its remains outward in twin jets at nearly the speed of light, researchers said. At its death it glowed so brightly that it outshone its entire galaxy by a million times. This brilliant flash travelled across space for 12.7 billion years to a planet that hadn’t even existed at the time of the explosion — our Earth. By analysing this light, astronomers learned about a galaxy that was otherwise too small, faint and far away for even the Hubble Space Telescope to see.
“This star lived at a very interesting time, the so-called dark ages just a billion years after the Big Bang,” said lead author Ryan Chornock of the Harvard-Smithsonian Centre for Astrophysics. “In a sense, we’re forensic scientists investigating the death of a star and the life of a galaxy in the earliest phases of cosmic time,” he added. The star announced its death with a flash of gamma rays, an event known as a gamma-ray burst (GRB). GRB 130606A was classified as a long GRB since the burst lasted for more than four minutes. It was detected by Nasa’s Swift spacecraft on June 6. “We were able to get right on target in a matter of hours. That speed was crucial in detecting and studying the afterglow,” Chornock says. A GRB afterglow occurs when jets from the burst slam into surrounding gas, sweeping that material up like a snowplow, heating it, and causing it to glow.
As the afterglow’s light travels through the dead star’s host galaxy, it passes through clouds of interstellar gas. Chemical elements within those clouds absorb light at certain wavelengths, leaving “fingerprints.” By splitting the light into a rainbow spectrum, astronomers can study those fingerprints and learn what gases the distant galaxy contained. Life could not have existed in the early universe because the elements of life, including carbon and oxygen, did not exist, researchers said.