Twelve for dinner: The Milky Way's feeding habits shine a light on dark matter

The artist has created a representation of the stars. These streams were the companion satellite galaxies that are being torn apart by the gravity of our galaxy. James Josephides and S5 collaborated.

The properties of dark matter are one step closer to being revealed thanks to a new map of twelve streams of stars.

Understanding the star streams is important for astronomy. They also tell us about the formation history of the Milky Way, which shows that the Milky Way has grown over billions of years by shredding and consuming smaller stellar systems.

The streams are being disrupted by the pull of the Milky Way. The study gives us a snapshot of the feeding habits of the Milky Way. The lead author of the paper said that our galaxy is getting fat as it gets older.

The shredded remains of neighboring small galaxies and star clusters are being torn apart by our own Milky Way, and Prof. Li and her international team of collaborators want to measure the properties of stellar streams.

The Anglo-Australian Telescope (AAT), a 4-meter optical telescope in Australia, was used by Li and her team to study a rich collection of stellar streams. The same property used by radar guns to catch speeding drivers was used by Li and her team to find out how fast individual stars were moving.

Professor Daniel Zucker says that S5 is dedicated to measuring as many streams as possible, which they can do very efficiently with the unique capabilities of the AAT.

The properties of stellar streams show the presence of dark matter. Professor Geraint F. Lewis of the University of Sydney says to think of a Christmas tree. On a dark night, we can see the Christmas lights, but not the tree. The shape of the lights shows the shape of the tree. The dark matter is revealed by stellar streams.

The astronomer can use the observations to find out where the stars were born. Professor Alex Ji of the University of Chicago is a co-author on the study. The nature of dark matter can be better understood by the two types of streams.

Prof. Li says that the new observations are essential for determining how the universe came to be. "This is one of the most intriguing questions, a question about our ultimate origins," Li said. It's the reason why we built an international collaboration to address this.

Observations from the European Gaia space mission were crucial to the success of S5. "Precisely measuring the positions and motions of stars is essential for identifying members of the stellar streams," says Dr. Sergey Koposov, a co-author of the study.

Li's team plans to make more observations on stellar streams. She is happy with the results as a starting point. There will be a lot of dedicated studies looking at stellar streams over the next decade. We are trail-blazers on this journey. It is going to be very exciting!

The results will be published in the Astrophysical Journal. The accepted version can be found here.

The Orbital and Chemical Properties of One Dozen Stellar Streams is available on

The Astrophysical Journal has information.

The Milky Way's feeding habits shine a light on dark matter.

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