The Splashback Radius of Planck-SZ clusters

Understand

We present evidence for the existence of the splashback radius in galaxy clusters selected using the Sunyaev-Zel'dovich effect.

• We show that the deprojected cross-correlation of galaxy clusters found in the Planck survey with galaxies detected photometrically in the Pan-STARRS survey, shows a sharp steepening feature (a logarithmic slope steeper than $-3$), which we associate with the splashback radius.
• We infer the three-dimensional splashback radius for the SZ cluster sample to be $r_{\rm sp}=1.85_{-0.30}^{+0.26}$ $h^{-1}$Mpc, where the cluster sample has an average halo mass $M_{500c}=3.0\times10^{14}h^{-1}M_\odot$ at an average redshift of $z=0.18$.
• The inferred value of the splashback radius appears consistent with the expected location for dark matter halos in the standard cold dark matter paradigm.