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The oldest spiral galaxy seen through gravitational lensing

Large galaxy clusters are the most massive structures in the Universe, comprising 10,000’s of galaxies. As predicted by Einstein, their large mass causes them to act as efficient ”cosmic telescopes” (called gravitational lenses), amplifying and boosting the size and brightness of distant galaxies which serendipitously lie behind them. The gains can be up to 50x, allowing us to study the processes of galaxy formation in galaxies at a level of detail that would otherwise have to wait a decade.

ASTRO 3D researchers have been able, for the first time, to look back 11 billion years, to directly witness the formation of the first, primitive spiral arms of a galaxy. Dr Tiantian Yuan and collaborators observed a gravitationally lensed spiral galaxy at redshift z = 2.54.

It is the most ancient spiral galaxy discovered and the second kinematically confirmed spiral at z > 2.

The galaxy, known as A1689B11, existing 11 billion years in the past, just 2.6 billion years after the Big Bang. At this time in the Universe formation, spiral galaxies are exceptionally rare and this one 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 with very little turbulence, which has never been seen before at this stage of the Universe.

The ASTRO 3D researchers used a powerful technique that combines gravitational lensing with the Nearinfrared Integral Field Spectrography (NIFS) on the Gemini North telescope in Hawai’I to verify the vintage and spiral nature of the galaxy.