Dissection of the Collisional and Collisionless Mass Components in a Mini Sample of CLASH and HFF Massive Galaxy Clusters at z ≈ 0.4

Abstract We present a multiwavelength study of the massive ( M 200 c ≈ ( 1 – 2 ) × 10 15 M ⊙ ) galaxy clusters RXC J2248.7−4431, MACS J0416.1−2403, and MACS J1206.2−0847 at z ≈ 0.4. Using the X-ray surface brightness of the clusters from the deep Chandra data to model their hot gas, we are able to disentangle this mass term from the diffuse dark matter (DM) in our new strong-lensing analysis, with approximately 50–100 secure multiple images per cluster, effectively separating the collisional and collisionless mass components of the clusters. At a radial distance of 10% of R 200c (approximately 200 kpc), we measure a projected total mass of (0.129 ± 0.001), (0.131 ± 0.001) and (0.137 ± 0.001) × M 200c, for RXC J2248, MACS J0416 and MACS J1206, respectively. These values are surprisingly similar considering the large differences in the merging configurations and, consequently, in the mass models of the clusters. Interestingly, at the same radii, the hot gas over total mass fractions differ substantially, ranging from 0.082 ± 0.001 to 0.133 ± 0.001, which reflects the various dynamical states of the clusters. Moreover, we do not find a statistically significant offset between the positions of the peak of the diffuse DM component and of the BCG in the more complex clusters of the sample. We extend the previous findings of a number of massive sub-halos that are higher than in numerical simulations to this sample of clusters. Our results highlight the importance of a proper separation of the different mass components to study the properties of DM in galaxy clusters in detail.