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Constraining the Collisional Nature of the Dark Matter Through Observations of Gravitational Wakes

Steven Furlanetto·Abraham Loeb
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Abstract

We propose to use gravitational wakes as a direct observational probe of the collisional nature of the dark matter. We calculate analytically the structure of a wake generated by the motion of a galaxy in the core of an X-ray cluster for dark matter in the highly-collisional and collisionless limits. We show that the difference between these limits can be recovered from detailed X-ray or weak lensing observations. We also discuss the sizes of sub-halos in these limits. Preliminary X-ray data on the motion of NGC 1404 through the Fornax group disfavors fluid-like dark matter but does not exclude scenarios in which the dark matter is weakly collisional.

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Steven Furlanetto, Abraham Loeb. 2001-07-30. Constraining the Collisional Nature of the Dark Matter Through Observations of Gravitational Wakes. https://doi.org/10.1086/324693

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