We present the direct detection of the splashback feature using the sample of massive galaxy clusters from the Local Cluster Substructure Survey. This feature is clearly detected in the stacked luminosity density profile from K-band magnitudes of spectroscopically confirmed cluster members. A Bayesian inference scheme ranked models including the splashback feature as more descriptive of the data with respect to models that do not allow for this transition. In addition, we exploited the extensive multi-wavelength LoCuSS dataset to test a wide range of proxies for the cluster formation history, finding the most significant dependence of the splashback feature location and scale according to the presence or absence of X-ray emitting galaxy groups in the cluster infall regions. This suggests a correlation between the properties of the cluster potential and its accretion rate and merger history. Clusters that are classified as old and dynamically inactive present stronger signatures of the splashback feature, with respect to younger, more active clusters. We are directly observing how fundamental dynamical properties of clusters reverberate across vastly different physical scales.

{"references": ["Bianconi M., Buscicchio R., Smith G.~P., McGee S.~L., Haines C.~P., Finoguenov A., Babul A., 2021, ApJ, 911, 136 (Arxiv:2010.05920)"]}