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June 25 (UPI) – New computer models designed to simulate the distribution of dwarf galaxies surrounding the Milky Way have clarified the existence of dark matter.
The models helped the researchers to simulate the "radial acceleration relationship," or RAR, the relationship between the motion of satellite galaxies causing attraction between galactic matter.
RAR considers the observed circular acceleration of a galaxy and the acceleration explained by the distribution of ordinary matter by the galaxy.
The new models also take into account the acceleration caused by dark matter.
"We have now simulated, for the first time, the RAR of dwarf galaxies assuming that dark matter exists," said Cristiano Porciani, a researcher at the Argelander Institute of Astronomy at the University of California. 39, University of Bonn. "It's turned out that they behave like smaller versions of larger galaxies."
The simulations also allowed scientists to determine how satellite galaxies would behave in the absence of dark matter. The models showed, without dark matter, that the RAR of a satellite galaxy would be more directly influenced by its distance from the parent galaxy.
The Gaia spacecraft of the European Space Agency is currently collecting precise details about the size, trajectory and speed of millions of stars, including stars inside the many dwarf galaxies surrounding the Milky Way.
Scientists hope that Gaia data can be used to test the predictions of the most recent RAR models with galactic observations. However, astronomers may have to wait for sufficient amounts of data.
"The individual measurements are not enough to test the small differences we found in our simulations," said Enrico Garaldi, a PhD student in Bonn. "But looking closer at the same stars improves the measurements each time, sooner or later it should be possible to determine whether dwarf galaxies behave as in a universe with dark matter – or not."
The existence of dark matter is implied by its gravitational influence, but it has not yet been detected directly. Most astronomers agree that dark matter exists. The presence of dark matter solves a variety of astrophysical problems.
However, some scientists have argued that other theories of gravity could plug some of the same theoretical gaps, making a new test necessary for the existence of dark matter.
Astronomers have detailed the latest test proposed in the journal Physical Review Letters.
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