Weak lensing constraints on splashback around massive clusters

Abstract

The splashback radius $r_\text{sp}$ separates the physical regimes of collapsed and infalling material around massive dark matter haloes. In cosmological simulations, this location is associated with a steepening of the spherically averaged density profile $\rho(r)$. In this work, we measure the splashback feature in the stacked weak gravitational lensing signal of $27$ massive clusters from the Cluster Canadian Comparison Project with careful control of residual systematics effects. We find that the shear introduced by the presence of additional structure along the line of sight significantly affects the noise at large clustercentric distances. Although we do not detect a significant steepening, the use of a simple parametric model enables us to measure both $r_\text{sp}=3.5^{+1.1}_{-0.7}$ comoving Mpc and the value of the logarithmic slope $\gamma = \log \rho / \log r$ at this point, $\gamma(r_\text{sp}) = -4.3^{+1.0}_{-1.5}$.