Star Explosion Illuminates Faint Galaxy from the Dark Ages

More than 12 billion years ago, a star exploded, blasting its remains outward in twin jets at nearly the speed of light. Now, astronomers are analyzing the light from this massive eruption, learning more about a galaxy that's too small, faint and far away for even the Hubble Space Telescope to see.

The star ended its life with a flash of gamma rays, an event known as a gamma-ray burst. At the time of its demise, Earth didn't even exist. Yet this brilliant flash travelled 12.7 billion years toward our planet, which is what now allows astronomers to observe the resulting light. First detected by NASA's Swift spacecraft, the gamma-ray burst lasted for more than four minutes and was labeled as GRB 130606A.

"The star lived at a very interesting time, the so-called dark ages just a billion years after the Big Bang," said Ryan Chornock, lead author of the new paper detailing the findings, in a news release. "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."

In order to learn more about the distant galaxy of this star, the researchers examined the afterglow of the GRB. This afterglow occurs when jets from the burst slam into surrounding gas, sweeping the material up like a snowplow, heating it and then causing it to glow. The researchers can then examine the wavelengths of light that different gases absorb and learn more about what types of gases are located in the distant galaxy.

So what did the astronomers find? It turns out that the galaxy contained only about one-tenth of the metals in our solar system. While rocky planets may have been able to form there, it's likely that life could not have existed.

"At the time this star died, the universe was still getting ready for life," said Chornock. "It didn't have life yet, but was building the required elements."

The findings don't only reveal a little bit more about the history of our ancient universe, though. They also show how new technology is allowing astronomers to glean more information than ever before. At a distance of 12.7 billion light-years, this GRB is one of the most distant gamma-ray bursts ever found, and researchers are planning on detecting even more distant ones in the future using the Giant Magellan Telescope.

The findings are published in The Astrophysical Journal.