“This type of spiral galaxy has never been seen before at this early epoch of the universe.”
Astronomers at Swinburne University of Technology in Australia found a spiral galaxy, called A1689B11, that emitted light 11 billion years ago, only 2.7 billion years after the Big Bang occurred. The team of researchers discovered it using an instrument called a near-infrared integral field spectrograph (NIFS) on the Gemini North telescope in Hawaii.
This allowed them to observe a cluster of galaxies acting as a gravitational lens. Gravitational lensing occurs when the light from distant objects (such as a spiral galaxy in this case) is bent and magnified by clusters of galaxies and dark matter in front of it. “This technique allows us to study ancient galaxies in high resolution with unprecedented detail,” said Dr. Tiantian Yuan, the astronomer who led the research team.
While the finding is extraordinary on its own, it gives us possible insight into how galaxies are formed according to the Hubble sequence – the classification of galaxies into ellipticals, spirals, lenticulars, and irregulars. “Spiral galaxies are exceptionally rare in the early universe,” Renyue Cen, one of the authors of the study said. “This discovery opens the door to investigating how galaxies transition from highly chaotic, turbulent discs to tranquil, thin discs like those of our own Milky Way galaxy.”
“We are able to look 11 billion years back in time and directly witness the formation of the first, primitive spiral arms of a galaxy,” Yuan explained.
“This galaxy is forming stars 20 times faster than galaxies today – as fast as other young galaxies of similar masses in the early universe. However, unlike other galaxies of the same epoch, A1689B11 has a very cool and thin disc, rotating calmly with surprisingly little turbulence. This type of spiral galaxy has never been seen before at this early epoch of the universe.”