Milky Way's own gravity can mimic dark matter clues, stellar stream simulations suggest
Most of the stars in our Milky Way galaxy sit neatly on a flat plane. But the space around our galaxy is much more chaotic. Rogue bands of stars called "stellar streams" orbit the Milky Way much like planets in our solar system orbit the sun.
New research suggests that the structure of a galaxy, rather than dark matter clumps, can create irregularities in stellar streams. Most stars in the Milky Way are arranged in a flat plane, but trails of stars called stellar streams orbit the galaxy in more chaotic patterns. Dark matter, an unknown substance that makes up most of the universe's mass, is thought to form a scaffold for galaxies to grow on, and it might be revealed indirectly through stellar streams.
However, a new study from the University of Washington challenges a leading theory that links dark matter and stellar streams. The study, published in The Astrophysical Journal, simulated four Milky Way-sized galaxies without dark matter clumps and observed that irregularities in stellar streams were primarily caused by the host galaxy's structure.
The simulation produced wiggles, kinks, spurs, branches, gaps, and clumps in the streams, with some becoming entirely torn apart by the galaxy's gravitational forces. While the results may be disappointing, the researchers believe they open new avenues for dark matter research, such as including dark matter clumps in future simulations to identify distinct irregularities.
The findings suggest that studying stellar streams could provide valuable insights into the nature of dark matter, despite the complexity of these celestial systems.
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- A Distant Stream of Stars May Offer New Clues to Dark Matter universetoday.com
