A new survey precisely links the shape of a galaxy to the ages of its stars
From left to right: ESO; Hubble/ESA and NASA
It’s hard to keep trim when you’re an old galaxy.
A survey of hundreds of galaxies found a clear link between their shapes and their stars’ ages, astronomers report April 23 in Nature Astronomy. Galaxies with younger stars are more squashed into flatter shapes, while galaxies with older stars are more blobby, says astronomer Jesse van de Sande of the University of Sydney.
“We’ve known for a long time that shape and age are linked in very extreme galaxies, very flat ones and very round ones,” he says. “This is the first time we’ve shown it’s true for all kinds of galaxies — all shapes, all ages, all masses.”
Van de Sande and his colleagues used observations of 843 galaxies from the SAMI Galaxy Survey to discover the relationship. The team quantified the galaxies’