Emulating Cluster-galaxy Cross-correlations for Cosmological Forecasting
Andres Salcedo, Ohio State University
The observed distribution of galaxies and galaxy clusters traces the underlying cosmic large-scale structure. This structure evolved gravitationally from initial fluctuations in the primordial matter-density field. As a result, large-scale structure is particularly sensitive to the cosmological properties of the primordial matter-density field. This sensitivity can be used to constrain cosmology through the combination of data from galaxy redshift surveys such as the Dark Energy Survey (DES) and dark-matter-only N-body simulations. Using a grid of cosmological N-body simulations, we construct a Taylor series expansion-based emulator for the cluster-galaxy projected cross-correlation function as well as the cluster weak lensing signal. We show that combining information from these probes across a large range of scales (0.3-30.0 Mpc) can help break degeneracies between cosmological and halo occupation distribution parameters that would otherwise degrade constraints from clustering or lensing alone. We present forecasts for a fiducial case corresponding to DES clusters and galaxies at redshifts z = 0.3 and z = 0.5, which yield percent-level constraints on the cosmological matter density and power-spectrum amplitude.
Abstract Author(s): Andres N. Salcedo, Benjamin Wibking, David Weinberg, Lehman Garrison, Douglas Ferrer, Jeremy Tinker, Daniel Eisenstein, Marc Metchnik, Philip Pinto