The Color Dependence of Galaxy Clustering Measured by the Hyper Suprime-Camera Survey

Abstract

We study the color-dependent statistics of galaxy clustering with the first public data release from the Hyper Suprime-Cam Subaru Strategic Program, which observes down to the same magnitude and depth as the upcoming Rubin Observatory Legacy Survey of Space and Time. Galaxies are known to be biased Poisson tracers of the underlying formerly Gaussian matter density field. In addition ,the density-morphology relation implicates that both “red” and “blue” galaxies should trace of the underlying density field differently. We select a magnitude-limited sample of ∼ 7, 000, 000 galaxies across the five “Wide” HSC-DR1 fields whose area sum to ∼ 108 square degrees. Separating the sample into four tomographic redshift bins whose edges have been selected to have roughly equal numbers of galaxies within each bin. In order to observe photometry from the rest-frame spectral energy distribution (SED) of our sources, we apply K-corrections to the data to mitigate the redshifting effects of Hubble flow. We execute the HSC clustering pipeline to deproject systematics from our fields of view and generate galaxy number density maps for each tomographic redshift bin across our observed fields. We then compute auto- and cross- matter power spectra within and across each bin to measure the nature of galaxy clustering. We qualify our results in the context of cosmological perturbation theory and the hierarchical growth of structure. This analysis was conducted with the aim of performing Halo Occupation Distribution fits to the power spectra of different galaxy color population, leading to new insights into the theory of galaxy formation and the ever-evolving architecture of Large Scale Structure.