The new galaxy is about 30 million light-years farther away than previous record-holder, a gamma-ray burst that faded within a few hours of its peak brightness, and 200 million light-years farther than the next most distant galaxy.
“We are approaching the limits of the observable universe with this observation,” said astronomer Michele Trenti of the University of Colorado, who was not involved in the new work. “It is quite a good improvement.”
The finding, published in the Oct. 21 Nature, could also give insight into how young stars helped make the universe transparent.
The new distance champion, deemed UDFy-38135539, was first spotted in late 2009 in a Hubble Space Telescope image called the Ultra Deep Field. The image captures 10,000 galaxies in the universe’s earliest epochs, several of which were good candidates for the most distant galaxy.
Because light takes time to travel across the universe, telescopes see these galaxies as they appeared billions of years ago. And because the universe is expanding, distant galaxies appear to be rapidly moving away from us. As the galaxies flee, the wavelength of the light they emit stretches out, or redshifts, similar to how an ambulance siren’s howl drops in pitch as it drives away.
Matt Lehnert of the Paris Observatory and colleagues picked the reddest galaxy in the Ultra Deep Field, then took 16 hours of follow-up observations with the SINFONI spectrograph on the Very Large Telescope in Chile.
Read more at Wired
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