UGC 10738
Original Published Date: 
Thursday, May 27, 2021

Full article issued by the ARC Centre of Excellence for All-Sky Astrophysics in 3D (ASTRO 3D).

The first detailed cross-section of a galaxy broadly similar to the Milky Way, published by researchers at ASTRO 3D, reveals that our galaxy evolved gradually, instead of being the result of a violent mash-up. The finding throws the origin story of our home into doubt.

The galaxy UGC 10738 turns out to have distinct ‘thick’ and ‘thin’ discs, similar to those of the Milky Way. This suggests, contrary to previous theories, that such structures are not the result of a rare long-ago collision with a smaller galaxy. They appear to be the product of more peaceful change.

The finding was made by a team led by two Discovery Early Career Researcher Award (DECRA) recipients, Nicholas Scott and Jesse van de Sande, from ASTRO 3D and The University of Sydney.

'Our observations indicate that the Milky Way’s thin and thick discs didn’t come about because of a gigantic mash-up, but a sort-of ‘default’ path of galaxy formation and evolution,' says Dr Scott.

'From these results, we think galaxies with the Milky Way’s particular structures and properties could be described as the ‘normal’ ones.'

Dr Scott also says that UGC 10738’s edge-on orientation meant it was simple to see which type of stars were in each disc.

'It’s a bit like telling apart short people from tall people,' he says. If you try to do it from overhead, it’s impossible, but it if you look from the side, it’s relatively easy.

Photo credit: 

The UGC 10738 galaxy is very similar to our own. Credit:  Centre de Données astronomiques de Strasbourg / SIMBAD / PanSTARRS.