Testing the Collisionless Nature of Dark Matter with the Radial Acceleration Relation in Galaxy Clusters

Abstract

The radial acceleration relation (RAR) represents a tight empirical relation between the inferred total and baryonic centripetal accelerations, g tot = GM tot ( < 100 kpc region, an SIDM model with σ / m = 0.3 cm 2 g −1 is disfavored at the 3.8 σ level with respect to the CDM model. This study demonstrates the power of the cluster-scale RAR for testing the collisionless nature of dark matter.