Speaker
Description
The halo assembly bias, a phenomenon referring to dependencies of the large-scale bias of a dark matter halo other than its mass, is a fundamental property of the standard cosmological model. By utilizing the constrained simulation Elucid that faithfully reproduces the observed structures larger than 2 Mpc in the local universe, for a sample of 634 massive clusters at z<0.12, we found their counterpart halos in Elucid and used the mass growth history of the matched halos to estimate the formation time of the observed clusters. This allowed us to construct a pair of early- and late-forming clusters, with a similar mass as measured via weak gravitational lensing, and large-scale biases differing at 3 sigma level, suggestive of the signature of assembly bias, which is further corroborated by the properties of cluster galaxies. Our study paves a way to further detect assembly bias based on cluster samples constructed purely on observed quantities.
