The Dark Matter Distribution in the Central Regions of Galaxy Clusters: Implications for Cold Dark Matter

摘要: We have undertaken a spectroscopic survey of gravitational arcs in carefully chosen sample six clusters, each containing dominant brightest cluster galaxy. use these systems to study the relative distributions dark and baryonic material central regions. Three clusters present both radial tangential provide particularly strong constraints on mass profiles, whereas other three display only act as control set. Following Sand, Treu, & Ellis, we analyze stellar velocity dispersion data for galaxies conjunction with arc redshifts lens models constrain profiles jointly. For find that inner matter density profile is consistent three-dimensional distribution, ρDM ∝ r-β, logarithmic slope β = 0.52 (68% CL). Similarly, gives an upper limit, < 0.57 (99% Taking together, mean distribution inconsistent standard NFW value, 1.0, at greater than 99% confidence. In addition, considerable cosmic scatter (Δβ ~ 0.3) values sample. no evidence preferentially yield flatter might be expected if they were biased subset. discuss validity our one-dimensional reconstruction method verify its conclusions by comparing results more rigorous ray-tracing code does not assume axial symmetry. Our extend considerably strengthen earlier presented Sand coworkers suggest relationship between visible cores much complex anticipated from recent simulations.