Scientists discover universe's oldest spiral galaxy

Galaxy formed just 2.6 billion years after the Big Bang.
By Laurel Kornfeld | Nov 08, 2017
Through the technique of gravitational lensing, astronomers have discovered the universe's oldest spiral galaxy, A1689B11, aged approximately 11 billion years.

Two magnified images of the ancient galaxy were found in two separate locations in the sky behind a galactic cluster known as Abell 1689.

When one light source is located behind a large object or cluster, gravitational lensing magnifies and bends the light of the more distant object, making it possible for scientists to view the latter, which would otherwise remain hidden.

By studying multiple images of the more distant object captured by the gravitational lens, scientists can obtain clear images of it. In this case, these images revealed the galaxy's distinct spiral shape.

A research team of scientists from Swinburne University of Technology in Melbourne, Australia, and the Australian National University in Canberra, Australia, discovered the ancient galaxy, which appears to us as it looked 11 billion years ago.

They then spent a year conducting followup observations of the galaxy with the Near-infrared Integral-Field Spectrograph on the Gemini North telescope in Hawaii, hoping to determine the velocity of its gases.

Still uncertain as to how a galaxy forms spiral arms, scientists hope this discovery will provide them with new insights into the phenomenon.

Most ancient and extremely distant galaxies are shaped like blobs.

"Detailed observations of spiral galaxies at high redshift will enable investigation into these physical processes that remain elusive in simulations," the researchers wrote in an article on the discovery published in the Astrophysical Journal.

Observations revealed a disk-shaped galaxy with one side spinning in Earth's direction and the other spinning away from Earth. One spiral arm is visible.

Associate astronomer at the Space Telescope Science Institute David Law, a co-discoverer of what is now the universe's second oldest spiral galaxy, said he hopes to compare current images of A1689B11 with followup observations planned using the Keck Telescopes' OSIRIS near-infrared integral field spectrograph.

When NASA's James Webb Space Telescope launches in 2019, scientists hope to use it to observe this galaxy, discover the earliest formation of spiral arms, and locate additional, similar galaxies.


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