Galaxy Correlation Statistics of Mock Catalogs for the DEEP2 Survey

Abstract

ABSTRACTThe Deep Extragalactic Evolutionary Probe 2 (DEEP2) project will obtain redshifts for ∼60,000 galaxies in the range z≃0.7–1.5 in a comoving volume of roughly 7 × 106 Mpc3 h−3 for a Λ cold dark matter universe. The survey will map four separate 2° × 0.°5 strips of the sky. To study the expected clustering within the survey volume, we have constructed mock galaxy catalogs from the GIF and Hubble Volume simulations developed by the Virgo consortium. We present two‐ and three‐point correlation analyses of these mock galaxy catalogs to test how well we will measure these statistics, particularly in the presence of selection biases, which will limit the surface density of galaxies that we can select for spectroscopy. We find that although the projected angular two‐point correlation function w(θ) is strongly affected, neither the two‐point nor three‐point correlation functions, ξ(r) and ζ(r), are significantly compromised. We will be able to make simple corrections to account for the small amount of bias introduced. We quantify the expected redshift distortions due to random orbital velocities of galaxies within groups and clusters (“fingers of God”) on small scales of ∼1 Mpc h−1 using the pairwise velocity dispersion σ12 and galaxy‐weighted velocity dispersion σ1. We are able to measure σ1 to a precision of ∼10%. We also estimate the expected large‐scale coherent infall of galaxies due to supercluster formation (“Kaiser effect”), as determined by the quadrupole‐to‐monopole ratio ξ2/ξ0 of ξ(rp, π). From this measure we will be able to constrain β to within ∼0.1 at z = 1.For the DEEP2 survey we will combine the correlation statistics with galaxy observables such as spectral type, morphology, absolute luminosity, and line width to enable a measure of the relative biases in different galaxy types. Here we use a counts‐in‐cells analysis to measure σ8 as a function of redshift and determine the relative bias between galaxy samples based on absolute luminosity. We expect to measure σ8 to within 10% and detect the evolution of relative bias with redshift at the 4–5 σ level, with more precise measurements for the brighter galaxies in our survey.