Masanori Sato, Takahiko Matsubara
It is crucial to understand and model a behavior of galaxy biasing for future ambitious galaxy redshift surveys. Using 40 large cosmological N-body simulations for a standard LambdaCDM cosmology, we study the cross-correlation coefficient between matter and halo density field, which is an indicator of stochasticity of bias, over a wide redshift range 0 \le z \le 3. The cross-correlation coefficient is important to extract information on the matter density field, e.g., by combining galaxy clustering and galaxy-galaxy-lensing measurements. We compare the simulation results with integrated perturbation theory (iPT) proposed by one of the present authors and standard perturbation theory (SPT) combined with a phenomenological model of local bias. The cross-correlation coefficient derived from the iPT agrees with N-body simulation results down to r \sim 15 (10) Mpc/h within 0.5(1.0)% for all redshifts and halo masses we consider. The SPT with local bias does not explain complicated behaviors on quasi-linear scales at low redshifts, while roughly reproduces general behavior of the cross-correlation coefficient on fully nonlinear scales. The iPT is powerful to predict the cross-correlation coefficient down to quasi-linear regimes with a high precision.
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http://arxiv.org/abs/1304.4228
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