Faster Movement, Flatter Shape--At Least For Galaxies

Khryss | Published 2017-09-17 19:45

Edwin Hubble, an American astronomer where the Hubble telescope was named after, first discovered that just about any galaxy in the universe will have one of 4 different shapes--spiral, elliptical, lenticular, and irregular. For more than 80 years, astronomers have been looking for ways to find out why galaxies are shaped like they are. But measuring the true 3D shape of a galaxy is a difficult problem. How do you measure something even bigger than the solar system?

Now, for the first time, astronomers can measure the shape of a galaxy by how fast it spins. The researchers published their study in the journal Monthly Notices of the Royal Astronomical Society. The research team’s leader, Dr Caroline Foster said: “This is the first time we’ve been able to reliably measure how a galaxy’s shape depends on any of its other properties – in this case, its rotation speed”. The researchers gathered data from 845 galaxies, more than three times the sample of the previous studies.

The researchers found that faster-spinning galaxies are thinner than slower-spinning ones. “And among spiral galaxies, which have disks of stars, the faster-spinning ones have more circular disks,” added Scott Croom of the University of Sydney and a member of the study.

The researchers gathered data with the use of SAMI or the Sydney-AAO Multi-object Integral field unit, an instrument that separates light into a frequency spectrum and records the signal using a camera. SAMI is developed by The University of Sydney and the Australian Astronomical Observatory. SAMI can look at 13 galaxies at a time and gives comprehensive data about star and gas movement inside of galaxies.

But galaxies get their shape mostly from what happened in the past like merging with other galaxies. Knowing this also gives us a glimpse of its history. It just goes to show that the more movement you do, the flatter you’ll be. Now does that remind you of something?

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