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arXiv · 1802.00081

A whirling plane of satellite galaxies around Centaurus A challenges cold dark matter cosmology

Oliver Müller·Marcel S. Pawlowski·Helmut Jerjen·Federico Lelli
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Abstract

The Milky Way and Andromeda galaxy are each surrounded by a thin plane of satellite galaxies that may be corotating. Cosmological simulations predict that most satellite galaxy systems are close to isotropic with random motions, so those two well-studied systems are often interpreted as rare statistical outliers. We test this assumption using the kinematics of satellite galaxies around the Centaurus A galaxy. Our statistical analysis reveals evidence for corotation in a narrow plane: of the 16 Centaurus A's satellites with kinematic data, 14 follow a coherent velocity pattern aligned with the long axis of their spatial distribution. In standard cosmology simulations, < 0.5% of Centaurus A-like systems show such behavior. Corotating satellite systems may be common in the Universe, challenging small-scale structure formation in the prevailing cosmological paradigm.

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Oliver Müller, Marcel S. Pawlowski, Helmut Jerjen, Federico Lelli. 2018-01-31. A whirling plane of satellite galaxies around Centaurus A challenges cold dark matter cosmology. https://doi.org/10.1126/science.aao1858

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