New research led by the University of California, Irvine addresses a fundamental debate in astrophysics: Must invisible dark matter exist to explain how the Universe works the way it does, or can physicists explain how things work based solely on in the matter that we can directly? observe?
Dark photons are hypothetical dark sector particles proposed to carry a force similar to the photon of electromagnetism but potentially connected to dark matter. Image credit: University of Adelaide.
“Our paper shows how we can use real observed relationships as a basis for testing two different models to describe the Universe,” said Dr. Francisco Mercado, a postdoctoral researcher at Pomona College.
We presented a powerful test to discriminate between the two models.
The test involved running computer simulations of both types of matter, normal and dark, to explain the presence of intriguing features measured in real galaxies.
The features of the galaxies we found would be expected to appear in a universe with dark matter, but would be difficult to explain in a universe without it.
We show that these features appear in observations of many real galaxies. If we take these data at face value, this reaffirms the position of the dark matter model as the one that best describes the Universe in which we live.
These features describe patterns in the motions of stars and gas in galaxies that appear to be possible only in a universe with dark matter.
The observed galaxies appear to obey a close relationship between the matter we see and the inferred dark matter we detect, so much so that some have suggested that what we call dark matter is actually evidence that our theory of gravity is wrong, he said. the University of California. Irvines teacher James Bullock.
What we showed is that dark matter not only predicts the relation, but for many galaxies it can explain what we see more naturally than modified gravity.
I come away even more convinced that dark matter is the right model.
The features also appear in observations made by advocates of a dark matter-free universe.
The observations we examined, the very observations where we found these features, were made by proponents of free dark matter theories, said Dr. Jorge Moreno, a researcher at Pomona College.
Despite their obvious presence, this community performed little or no analysis of these characteristics.
It took people like us, scientists who work with both normal and dark matter, to start the conversation.
We expect that the debate within our research community will continue after the study, but that there may be room for common ground, as we also found that these features only appear in our simulations when there is dark matter and normal matter in the Universe. .
As stars are born and die, they explode in supernovae, which can shape the centers of galaxies, naturally explaining the existence of these features.
Simply put, the features we have examined in the observations require both the existence of dark matter and the incorporation of normal matter physics.
Now that the dark matter model of the Universe appears to be the leading one, the next step is to see if it remains consistent across an entire dark matter universe.
It would be interesting to see if we could use this same relationship even to distinguish between different models of dark matter, said Dr. market
Understanding how this relationship changes under different dark matter models could help us constrain the properties of dark matter itself.
The paper was published online at Monthly Notices of the Royal Astronomical Society.
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Francisco J. Mercado et al. Hooks & Bends in the Radial Acceleration Relation: Discriminative Tests of Dark Matter and MOND. MNRAS 530 (2): 1349-1362; doi: 10.1093/mnras/stae819
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