Most distant disk galaxy discovered

The disk galaxy called REBELS-25, whose rotation and structure were determined using ALMA, appears to be as ordered as today’s galaxies. This is surprising because, based on current knowledge, galaxy formation from such early galaxies should appear more chaotic.

The ancient galaxy resembles our Milky Way
“Seeing a galaxy that looks and rotates so much like our own Milky Way poses a major challenge to our understanding of how quickly galaxies in the early universe evolve into the ordered galaxies of the current cosmos,” explains Lucie Rowland of the University Lead out.

“Based on our understanding of galaxy formation, we expect most early galaxies to be small and chaotic,” explains Jacqueline Hodge, astronomer at Leiden University and co-author of the study. It was previously thought that the chaotic early galaxies evolved into more uniform shapes at an incredibly slow pace.

Discovery calls previous theories into question
Current theories suggest that a galaxy roughly as ordered as our Milky Way – a rotating disk with distinct structures such as spiral arms – would have undergone billions of years of evolution. However, the discovery of REBELS-25 calls this timing into question.

Surprisingly, the data collected with ALMA also suggests more developed features of the REBELS-25 galaxy that are similar to those of the Milky Way, such as a central, elongated bar and even spiral arms – although further observations are needed to confirm this, the study said. researchers. .

Future observations of REBELS-25, as well as other discoveries of early rotating galaxies, could potentially change our understanding of the early formation of galaxies and the evolution of the universe as a whole, the ESO website says.

Unique location on a high plateau in Chile
The ALMA telescope network (pictured above) senses radio waves from space in the lower energy range of the electromagnetic spectrum. The super telescope, which opened in 2013, is located more than 5,000 meters above sea level on the Chajnantor Plateau in Chile’s Atacama Desert. It is managed by ESO, of which Austria is a member, and by partners from North America, East Asia and Chile.