Astronomers spot galaxy as it appeared 2 billion years after the Big Bang
9 Oct 2008, 1301 Hrs

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Washington, Oct 9 Astronomers at the California Institute of Technology (Caltech) and their colleagues used a rare cosmic alignment and modern adaptive optics to reveal a galaxy as it appeared 2 billion years after the Big Bang.

Apart from providing detailed insight into the nature of the young star-forming galaxy, the technique also determined how that galaxy may eventually evolve to become a system like our own Milky Way.

The team made their observations by coupling two techniques, gravitational lensing and laser-assisted guide star (LGS) adaptive optics (AO) on the 10-meter Keck Telescope in Hawaii.

Adaptive optics corrects for the blurring effects of Earth's atmosphere by real-time monitoring of the signal from a natural or artificial guide star.

Gravitational lensing enlarged the distant galaxy in angular size by a factor of about eight in each direction.

Together with the enhanced resolution using adaptive optics, this allowed the team to determine the internal velocity structure of the remote galaxy, located 11 billion light-years from Earth, and hence its likely future evolution.

The researchers found that the distant galaxy, which is typical in many respects to others at that epoch, shows clear signs of orderly rotation.

The finding, in association with observations conducted at millimeter wavelengths, which are sensitive to cold molecular gas (an indicator of galactic rotation), suggests that the source is in the early stages of assembling a spiral disk with a central nucleus similar to those seen in spiral galaxies at the present day.

"This is the most detailed view we have yet seen of a young, early-epoch galaxy, and it has given us unique insight into how such systems begin to take on the familiar characteristics of spiral galaxies like our own Milky Way," said Richard Ellis, Steele Professor of Astronomy at Caltech.

"It is an exciting discovery that heralds the kind of science that will be routine when the Thirty Meter Telescope comes on-line," he added.

When completed in the latter half of the next decade, TMT's giant primary mirror and improved optics will produce images with an angular resolution three times better than the 10-meter Keck and 12 times better than the Hubble Space Telescope, at similar wavelengths. (ANI)