Saturday, November 17, 2012

Hubble space telescope helps discover most remote galaxy

Astronomers have revealed what is probably the most remote galaxy yet seen in the Universe by combining the power of the NASA/ESA Hubble Space Telescope, NASA’s Spitzer Space Telescope and one of nature’s zoom lenses. The object offers a glance back into a time when the world was only 3% of its present age of 13.7 billion years.

We see the recently discovered galaxy, named MACS0647-JD, as it was 420 million years after the Big Bang. Its light has travelled for 13.3 billion years to reach Earth, which corresponds to a redshift of around 11.

This is the newest discovery from the Cluster Lensing and Supernova review with Hubble, which uses enormous galaxy clusters as cosmic telescopes to enlarge remote galaxies behind them, an effect called gravitational lensing

Along the way, 8 billion years into its trip, the galaxy’s light took a detour along many paths around the enormous galaxy cluster MACS J0647.7+7015. Due to the gravitational lensing, the team observed three magnified images of MACS0647-JD with Hubble.

The cluster’s gravity boosted the light from the distant galaxy, making the images show far brighter than they otherwise would, although they motionless appear as tiny dots in Hubble’s portrait.

The estimated mass of this baby galaxy is roughly equal to 100 million or a billion suns, or 0.1-1% the mass of our Milky Way’s stars. “This object may be one of many building blocks of a galaxy,” Dan Coe, lead author of the study said.

The object is so little it may be in the first stages of galaxy formation, with analysis showing the galaxy is less than 600 light-years across. For contrast the Milky Way is 150 000 light-years across.


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