Bar-shaped features in spiral galaxies accelerate aging process

Astronomers from the University of Portsmouth have discovered that bar-shaped features in spiral galaxies accelerate the galaxy aging process.

The astronomers found that the fraction of spiral galaxies with bar features has doubled in the last eight billion years - the latter half of the history of the universe.

University of Portsmouth postgraduate researcher Tom Melvin and the rest of the Galaxy Zoo science team used classifications provided by citizen scientists to select spiral galaxies across the universe for the study.

Mr. Melvin's group studied how the fraction of spiral galaxies with bars changed over time.

They found that 8 billion years ago only 11 per cent of spirals had bars, but by 2.5 billion years ago this proportion had doubled.

In the present day universe two-thirds of galaxies have bars. And the more massive the galaxy, the more likely this is to be the case.

Dr. Karen Masters, also from Portsmouth University and Project Scientist for Galaxy Zoo, said that it looks as though bars really are bad for spiral galaxies. As a bar grows in a galaxy, it is less likely to have any new stars being born and the galaxy settles down to a sedate maturity.

The study has been published in the journal Monthly Notices of the Royal Astronomical Society.