Feb. 2 (UPI) — No two galaxies are alike. While each galaxy features a variety of structural quirks, galaxies don’t exist in isolation — and researchers have devised a method for observing multiple galaxies at once.
To better understand both the breadth of galactic diversity and the different ways galaxies relate to and interact with one another, researchers in Australia developed a unique imaging instrument to survey 13 galaxies at a time.
Scientists affixed their instrument, the Sydney-AAO Multi-Object Integral-Field Spectrograph, or SAMI, to a 4-meter telescope operated by the Australian National University.
For seven years, researchers used SAMI to observe galaxies, completing a survey of more than 3,000 galaxies. SAMI allowed astronomers to image the surveyed galaxies in a variety of colors, or spectra, and from multiple viewpoints.
The survey’s three-dimensional perspective helped scientists study how different galaxies grew and altered their spin or trajectories over time, as well as how different galaxies interacted with one another.
Researchers detailed the results of the SAMI Survey in a new paper, published this week in the journal Monthly Notices of the Royal Astronomical Society.
“The SAMI survey lets us see the actual internal structures of galaxies, and the results have been surprising,” lead study author Scott Croom said in a news release.
“The sheer size of the SAMI Survey lets us identify similarities as well as differences, so we can move closer to understanding the forces that affect the fortunes of galaxies over their very long lives,” said Croom, an astronomy professor at the University of Sydney.
Teams of astronomers are already using the newly detailed survey datasets to study how galaxies relate to one another in space.
While some galaxies persist in sparse pockets of the cosmos, mostly free from influence of neighbors, other galaxies can be found squeezed into dense clusters.
One new study inspired by the SAMI Survey data showed the direction of a galaxy’s spin is strongly influenced by the surrounding galaxies. Another group found the speed at which a galaxy spins is determined by its mass, while a third study found galaxies tend to dramatically slow star production as they are pulled into dense galactic clusters.
“The SAMI Survey was set up to help us answer some really broad top-level questions about galaxy evolution,” said co-author Matt Owers.
Owers, an astronomer at Macquarie University in Australia, said the new detailed information researchers have gathered could help understand a variety of fundamental questions — including why galaxies look different depending on where they are located in the galaxy.
“What processes stop galaxies forming new stars and, conversely, what processes drive the formation of new stars? Why do the stars in some galaxies move in a highly ordered rotating disk, while in other galaxies their orbits are randomly oriented?” Owers said.
Though the SAMI Survey has ended, the researchers expect the publicly available datasets to inspire a variety of new studies.
