The signature spiral arms of the Milky Way galaxy were likely formed by an epic collision between the Milky Way and the Sagittarius Dwarf galaxy, according to a University of Pittsburgh researcher and his collaborators whose findings were published last week in the prestigious British journal Nature.
The results of supercomputer simulations by Christopher W. Purcell, postdoctoral research associate in the Department of Physics and Astronomy in Pitt’s School of Arts and Sciences, and colleagues were reported in a paper titled “The Sagittarius Impact as an Architect of Spirality and Outer Rings in the Milky Way.”
This paper is the first to identify Sagittarius as the architect of spiral structure in our Milky Way: “It presents a new and somewhat unexpected way of thinking about why the galaxy we live in looks the way it does,” says Purcell. “Cosmologically speaking, it demonstrates the idea that relatively small impacts like this can have a dramatic impact on the structure of galaxies throughout the universe,” he adds.
This idea had been assumed theoretically, but never demonstrated.
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