AMICO galaxy clusters in KiDS-1000: Splashback radius from weak lensing and the cluster–galaxy correlation function

Aims. We present the splashback radius analysis of the Adaptive Matched Identifier of Clustered Objects (AMICO) galaxy cluster sample in the fourth data release of the Kilo Degree Survey (KiDS). The sample contains 9049 rich galaxy clusters within [0:1; 0:8], with shear measurements available for 8730 of them. Methods. We measured and modelled the stacked reduced shear, gt, and the cluster–galaxy correlation function, wcg, in bins of observed intrinsic richness and redshift. Building on the methods employed in recent cosmological analyses, we modelled the average splashback radius, rsp, of the underlying dark matter halo distribution, accounting for the known systematic uncertainties that affect measurements and theoretical models. Results. By modelling gt and wcg separately in the cluster-centric radial range [0:4; 5] h-1 Mpc, we constrain rsp, the massaccretion rate, and the relation between Rsp   rsp=r200m and the peak height,  200m, over the mass range M200m 2 [0:4; 20] 1014 h-1 M. The two probes provide consistent results that also agree with  -cold dark matter model predictions. Our Rsp constraints are consistent with those from previous observations. For gt and wcg, we achieve a precision of 14% and 10% per cluster stack, respectively. The higher precision of wcg, enabled by its combination with weak-lensing constraints on the mass-richness relation, highlights the complementarity of lensing and clustering in measuring rsp and constraining the properties of the infalling material region.