Farthest Galaxy Found, Perhaps

posted: 12 February 2008 11:38 pm ET

: An artist's impression of an embryonic galaxy brimming with star birth in the early universe, less than a billion years after the Big Bang. Credit: NASA, ESA, and G. Bacon (Space Telescope Science Institute)
: A massive cluster of yellowish galaxies magnifies what may the farthest galaxy ever seen (in white box). It does not show up in the visible-light image (top, right), because its light is stretched to invisible infrared wavelengths by the Universe's expansion. Credit: NASA, ESA, L. Bradley (JHU), R. Bouwens (UCSC), H. Ford (JHU)and G. Illingworth (UCSC)

Astronomers have glimpsed what may be the farthest galaxy we've ever seen, providing a picture of a baby galaxy born soon after the beginning of the universe.

Images taken with the Hubble Space Telescope have revealed the galaxy at almost 13 billion light-years away, making it the strongest candidate for the most distant galaxy ever seen, said European Southern Observatory astronomer Piero Rosati, who helped make the discovery.

Since the galaxy is so far away, its light took ages to reach us, so what we see now is a snapshot of how this galaxy looked 13 billion years ago. At that point in time, the galaxy would have been newly formed, so the new observations provide a baby picture.

"We certainly were surprised to find such a bright young galaxy 13 billion years in the past," said astronomer Garth Illingworth of the University of California, Santa Cruz, a member of the research team. "This is the most detailed look to date at an object so far back in time."

The young galaxy, called A1689-zD1, was born about 700 million years after the Big Bang that scientists think created the universe. For most of its early life, the universe languished in "dark ages" when matter in the expanding universe cooled and formed clouds of hydrogen. Eventually matter began to clump into stars and galaxies that radiated light, heating up the universe and clearing the fog.

Scientists think this newly discovered galaxy may have been one of the first to form and help end the dark ages.

"This galaxy presumably is one of the many galaxies that helped end the dark ages," said astronomer Larry Bradley of Johns Hopkins University in Baltimore, leader of the research team. "Astronomers are fairly certain that high-energy objects such as quasars did not provide enough energy to end the dark ages of the universe. But many young star-forming galaxies may have produced enough energy to end it."

The discovery was made possible by a natural magnifying glass — the galaxy cluster Abell 1689, which lies between us and the distant galaxy. Abell 1689's gravity is so strong it bends light that passes near it, acting like a giant zoom lens that magnifies what we see.

"This galaxy lies near the region where the galaxy cluster produces the highest magnification," Rosati said, "which was essential to bring this galaxy within reach of Hubble and Spitzer."

The discovery, announced today, will be detailed in the Astrophysical Journal.