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

## TL;DR

This paper introduces a new gravitational lensing method to detect asymmetries in dark matter distributions, applied to galaxy cluster Abell 3827, providing tentative evidence of skewness consistent with self-interacting dark matter models.

## Contribution

The paper develops a gravitational lensing technique incorporating a skewness parameter to identify asymmetric dark matter distributions in galaxy clusters.

## Key findings

- Tentative detection of skewness in dark matter distribution in Abell 3827
- Skewness measurement aligns with previous offset findings
- Method shows potential for future dark matter collision studies

## Abstract

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. In the galaxy whose dark matter peak has previously been found to be offset, we tentatively measure a skewness $s=0.23^{+0.05}_{-0.22}$ in the same direction as the peak offset. Our method may be useful in future gravitational lensing analyses of colliding galaxy clusters and merging galaxies.