A pair of early- and late-forming galaxy cluster samples in the local Universe

Elucid is a constrained simulation of the local universe that reproduces well the large-scale structure as observed by the Sloan Digital Sky Survey (SDSS).  Finding a one-to-one correspondence between the Elucid dark matter halos and observed massive galaxy clusters in SDSS, and making use of the halo formation history as provided by Elucid, we have constructed a pair of early-forming and late-forming cluster samples that have similar mean masses (as confirmed by weak lensing).  We have used these samples to show the presence of assembly bias at cluster scales, and have studied the difference in the properties of these two samples, including the magnitude gap, and the properties of the intracluster medium as revealed by X-ray and Sunyaev-Zel'dovich effect observations.