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 between the inferred total and baryonic centripetal accelerations, g tot = GM (< r )/ 2 bar , observed in galaxies galaxy clusters. correlation these two quantities can provide insight into nature of dark matter. Here we use BAHAMAS, state-of-the-art suite cosmological hydrodynamical simulations, to characterize RAR cluster-scale halos for both cold collisionless matter (CDM) self-interacting (SIDM) models. SIDM generally have reduced central densities, which reduces region when compared with CDM. We compare RARs clusters simulated different models from CLASH observations. Our comparison shows that CDM model provides an excellent match obtained by Tian et al. including high-acceleration regime probed brightest cluster (BCGs). By contrast, larger cross section yield increasingly poorer matches RAR. Excluding BCG regions results weaker but still competitive constraint on section. Using data outside < 100 kpc region, σ / m 0.3 cm −1 is disfavored at 3.8 level respect model. This study demonstrates power testing