Astronomers discover most distant galaxy ever

The new distance measurement also enabled the astronomers to determine that EGS-zs8-1 is still forming stars rapidly…

galaxy NASA
An artist's rendering of the galaxy, known by its catalog name z8_GND_5296, in seen this handout provided by NASA October 23, 2013. (Reuters)

Astronomers have found the most distant galaxy in the universe, measured at 13.1 billion light-years from Earth.
The exceptionally luminous galaxy, EGS-zs8-1, was originally identified based on its particular colours in images from NASA’s Hubble and Spitzer space telescopes.

The astronomers led by Yale University and the University of California-Santa Cruz determined its exact distance from Earth using the powerful MOSFIRE instrument on the WM Keck Observatory’s 10-metre telescope, in Hawaii.
They found the galaxy lies 13.1 billion light-years from Earth, the largest distance ever measured between Earth and another galaxy, ‘’ reported.

The new distance measurement also enabled the astronomers to determine that EGS-zs8-1 is still forming stars rapidly, about 80 times faster than our galaxy.

The light from distant galaxies we see via today’s advanced telescopes travels for billions of years before it reaches us – so we’re seeing what those galaxies looked like billions of years ago.

“It has already built more than 15 per cent of the mass of our own Milky Way today,” said Pascal Oesch, a Yale astronomer and lead author of the study published in Astrophysical Journal Letters.

“But it had only 670 million years to do so. The universe was still very young then,” Oesch said.
The new observations establish EGS-zs8-1 at a time when the universe was undergoing an important change: The hydrogen between galaxies was transitioning from a neutral state to an ionised state.

“It appears that the young stars in the early galaxies like EGS-zs8-1 were the main drivers for this transition, called reionisation,” said Rychard Bouwens of the Leiden Observatory, co-author of the study.

Taken together, the new Keck Observatory, Hubble, and Spitzer observations also pose new questions. They confirm that massive galaxies already existed early in the history of the universe, but they also show that those galaxies had very different physical properties from what is seen around us today.

Astronomers now have strong evidence that the peculiar colours of early galaxies – seen in the Spitzer images – originate from a rapid formation of massive, young stars, which interacted with the primordial gas in these galaxies.

The observations underscore the exciting discoveries that are possible when NASA’s James Webb Space Telescope is launched in 2018, the researchers said.

In addition to pushing the cosmic frontier to even earlier times, the telescope will be able to dissect the galaxy light of EGS-zs8-1 seen with the Spitzer telescope and provide astronomers with more detailed insights into its gas properties, they said.

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First published on: 06-05-2015 at 13:36 IST