A test for skewed distributions of dark matter and a possible detection in galaxy cluster Abell 3827

Understand

Simulations of self-interacting dark matter (SIDM) predict that dark matter should lag behind galaxies during a collision.

• If the interaction is mediated by a high-mass force carrier, the distribution of dark matter can also develop asymmetric dark matter tails.
• To search for this asymmetry, we compute the gravitational lensing properties of a mass distribution with a free {\em skewness} parameter.
• We apply this to the dark matter around the four central galaxies in cluster Abell~3827.