The effects of assembly bias on cosmological inference from galaxy-galaxy lensing and galaxy clusters

Abstract

The combination of galaxy-galaxy lensing (GGL) and galaxy clustering is a promising route to measuring the amplitude of matter clustering and testing modified gravity theories of cosmic acceleration. Halo occupation distribution (HOD) modeling can extend the approach down to nonlinear scales, but galaxy assembly bias could introduce systematic errors by causing the HOD to vary with large scale environment at fixed halo mass. We investigate this problem using the mock galaxy catalogs created by Hearin & Watson (2013, HW13), which exhibit significant assembly bias because galaxy luminosity is tied to halo peak circular velocity and galaxy colour is tied to halo formation time. The preferential placement of galaxies (especially red galaxies) in older halos affects the cutoff of the mean occupation function $⟨N_{\text{cen}}(M_{\text{min}})⟩$ for central galaxies, with halos in overdense regions more likely to host galaxies. The effect of assembly bias on the satellite galaxy HOD is minimal. We introduce an extended, environment dependent HOD (EDHOD) prescription to describe these results and fit galaxy correlation measurements. Crucially, we find that the galaxy-matter cross-correlation coefficient, $r_{gm}\equiv {\xi }_{gm}\cdot [{\xi }_{mm}{\xi }_{gg}{]}^{-1/2}$, is insensitive to assembly bias on scales $r\gtrsim 1h^{-1}\text{Mpc}$, even though ${\xi }_{gm}$ and ${\xi }_{gg}$ are both affected individually. We can therefore recover the correct ${\xi }_{mm}$ from the HW13 galaxy-galaxy and galaxy-matter correlations using either a standard HOD or EDHOD fitting method. For $M_r\le -19$ or $M_r\le -20$ samples the recovery of ${\xi }_{mm}$ is accurate to 2% or better. For a sample of red $M_r\le -20$ galaxies we achieve 2% recovery at $r\gtrsim 2h^{-1}\text{Mpc}$ with EDHOD modeling but lower accuracy at smaller scales or with a standard HOD fit.

Figure 17 conveys the key result; experts can start at the conclusions

References in corpus (18)

• The EAGLE project: Simulating the evolution and assembly of galaxies and their environments
• Dark Energy and the Accelerating Universe
• The spin and shape of dark matter haloes in the Millennium simulation of a LambdaCDM universe
• Halo assembly bias and its effects on galaxy clustering
• KiDS-450 + 2dFLenS: Cosmological parameter constraints from weak gravitational lensing tomography and overlapping redshift-space galaxy clustering
• Lensing is Low: Cosmology, Galaxy Formation, or New Physics?
• The dependence of dark halo clustering on the formation epoch and the concentration parameter
• Introducing Decorated HODs: modeling assembly bias in the galaxy-halo connection
• The galaxy-halo connection from a joint lensing, clustering and abundance analysis in the CFHTLenS/VIPERS field
• The Weak Lensing Signal and the Clustering of BOSS Galaxies II: Astrophysical and Cosmological Constraints
• Environmental Dependence of Dark Matter Halo Growth I: Halo Merger Rates
• The Dependence of the Mass Assembly History of Cold Dark Matter Halos on Environment
• Environmental Dependence of Cold Dark Matter Halo Formation
• The Clustering of Massive Halos
• The assembly bias of dark matter haloes to higher orders
• Spatial Clustering of Dark Matter Halos: Secondary Bias, Neighbor Bias, and the Influence of Massive Neighbors on Halo Properties
• The nature of assembly bias - I. Clues from a LCDM cosmology
• The nature of assembly bias - II. Halo spin

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