Astronomers have 12 New Tools to Study Dark Matter Mysteries

Astronomers are one step closer to revealing the properties of dark matter enveloping our Milky Way galaxy, thanks to a new map of twelve streams of stars orbiting within our galactic halo. Understanding these star streams is very important for Astronomers.

The dark matter that holds the stars in their orbits, they also tell us about the formation history of the Milky Way, revealing that the Milky Way has steadily grown over billions of years by shredding and consuming smaller stellar systems. University of Toronto Professor Ting Li, the lead author of the paper said that they are seeing these streams being disrupted by the Milky Way’s gravitational pull, and eventually becoming part of the Milky Way.

This study gives us a snapshot of the Milky Way’s feeding habits, such as what kinds of smaller stellar systems it ‘eats’. As our galaxy is getting older, it is getting fatter. Prof. Li and her international team of collaborators initiated a dedicated program—the Southern Stellar Stream Spectroscopic Survey (S5)—to measure the properties of stellar streams: the shredded remains of neighboring small galaxies and star clusters that are being torn apart by our own Milky Way.Researchers are the first group of scientists to study such a rich collection of stellar streams, measuring the speeds of stars using the Anglo-Australian Telescope (AAT), a 4-meter optical telescope in Australia.

Li and her team used the Doppler shift of light, the same property used by radar guns, to catch speeding drivers to  find out how fast individual stars are moving.Researchers plan to produce more measurements on stellar streams in the Milky Way. She is pleased with these results as a starting point. Over the next decade, there will be a lot of dedicated studies looking at stellar streams. They are trail-blazers and pathfinders on this journey. The results have been accepted for publication in the American Astronomical Society’s Astrophysical Journal.