Presentation #139.24 in the session Galaxy Clusters/Large Scale Structure, Cosmic Distance — iPoster Session.
Secondary (or ”assembly’) bias is a currently unexplained phenomenon in simulations of large-scale structure formation in which the clustering of dark matter halos of equal mass depends on a secondary property, such as halo age or concentration. Understanding the origin of secondary bias will aid in constraining cosmological models and better explain how galaxies cluster. One proposed explanation for the origin of secondary bias is the truncation of mass accretion in lower mass halos due to the tidal fields from surrounding masses, called ‘arrested development.’ We propose a new method to test this explanation for secondary bias using a halo mass accretion history function to model the mass accretion histories of halos. By fitting a mass accretion history function to a halo over early times and extrapolating, the mass truncation of an arrested development halo can be mitigated, and we can measure the predicted clustering of halos in the absence of arrested development. We apply this method using a high-resolution dark matter only simulation and show a reduction in the secondary bias signal, offering additional evidence in support of arrested development as a cause of secondary bias.