A new study, the first to trickle out of Galaxy Zoo’s second crowd-sourced scientific effort, buoys the idea that bars somehow encourage galaxies to form big, blue and short-lived stars, as well as funnel gas and dust to supermassive black holes lurking at their cores. In the process, bars may quickly consume star-making materials to leave behind only a “dead” galaxy of red and fading stars.
“Basically, as you go from the really youthful galaxies to the dead ones, more and more frequently we see bars in them,” said Kevin Schawinski, an astronomer at Yale University and co-author of the study, set to appear in an upcoming edition of the Monthly Notices of the Royal Astronomical Society. “Our immediate suspicion is that bars are involved in speeding galaxy evolution.”
Schawinski said the work isn’t proof that bars shorten galaxies’ star-forming lifespans — it could be the other way around, with bars being a product of dying galaxies. But he said the data backs the first idea, which is shared among many astronomers.
“Bars seem to help exhaust supplies of gas, pushing galaxies to a passive state and no longer forming any stars. This is inline with our results and what others are saying,” Schawinski said. “The Milky Way, which is more or less agreed to be a barred spiral, may be an example of a galaxy in transition from an active state to something anemic and passive.”
George Djorgovski, an astronomer at Caltech who described his team as “in a friendly competition of sorts” with Galaxy Zoo, said the new research is interesting and does support existing ideas in the field.
“More than anything it illustrates how citizen science approach can be used very effectively, both in research and outreach,” Djorgovski said. “It’s a pretty exciting way of doing science, and Galaxy Zoo is certainly the most successful to date.”
Read more at Wired
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