Hubble Space Telescope Finds Most Distant Galaxy Candidate Yet
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UDFj-39546284 appears as a faint red blob in this ultra-deep–field exposure taken with NASA's Hubble Space Telescope. Photo by NASA, ESA, Garth Illingworth, Rychard Bouwens and the HUDF09 Team
Astronomers pushing the limits of Hubble's capabilities found a dim object, called UDFj-39546284, located approximately 13.2 billion light-years away. This places the object roughly 150 million light-years more distant than the previous record holder reported last October.
Evidence suggests UDFj-39546284 is a compact galaxy of blue stars that existed 480 million years after the Big Bang, when the universe was just three to four percent of its current age. The Big Bang is an explosion of dense matter that astronomers believe marked the origin of the universe.
More than 100 such mini-galaxies would be needed to make up our own galaxy, the Milky Way.
Observations were based on infrared data gathered from the telescope's Wide Field Planetary Camera 3, which positively identified the object in the late summer of 2009 and 2010. Researchers were able to see dramatic changes in galaxies that spanned roughly 480 to 650 million years after the Big Bang. What they discovered was the rate of star birth in the universe increased by 10 times during this 170-million-year period.
“We’re getting back very close to the first galaxies, which we think formed around 200 to 300 million years after the Big Bang,” said Garth Illingworth of the University of California at Santa Cruz, who led the study. "The rapid rate at which the star birth is changing tells us if we go a little further back in time we're going to see even more dramatic changes." Their previous searches found 47 galaxies at somewhat later times, when the universe was roughly 650 million years old.
Hubble is a project between NASA and the European Space Agency. Astronomers will be able to observe even earlier times, when the first stars and galaxies were forming, with the James Webb Space Telescope―Hubble's successor. It is planned for launch later this decade and will confirm UDFj-39546284's status.
The study is published in the Jan. 27 issue of Nature.
