利用弱重力透鏡效應探測星系團中的暗質次結構

Abstract

According to the cold dark matter (CDM) model, cosmic structures are formed hierarchically through a succession of mergers and accretions. Since more massive structures are merged from less massive structures, there should be some surviving dark matter substructures (subhalos) in cluster-sized dark matter halos. Numerous numerical simulations have shown that about (5-20)% of the total mass of a cluster is contributed by these subhalos. In addition, the size and mass of subhalos depend strongly on the cluster-centric radius due to the tidal force induced by the host halo. Therefore, the comparison between observation of subhalos properties and the simulation prediction is important, in order to gain a deeper understanding of the growth and evolution of the clusters. Here we present the technique of galaxy-galaxy lensing using both the N-body simulation and the observational data in order to explore substructures in cluster halos.