On the signature of the baryon-dark matter relative velocity in the two and three-point galaxy correlation functions

Abstract

We develop a configuration-space picture of the relative velocity between baryons and dark matter that clearly explains how it can shift the BAO scale in the galaxy-galaxy correlation function. The shift occurs because the relative velocity is non-zero only within the sound horizon and thus adds to the correlation function asymmetrically about the BAO peak. We further show that in configuration space the relative velocity has a localized, distinctive signature in the three-point galaxy correlation function (3PCF). In particular, we find that a multipole decomposition is a favorable way to isolate the relative velocity in the 3PCF, and that there is a strong signature in the l=1 multipole for triangles with 2 sides around the BAO scale. Finally, we investigate a further compression of the 3PCF to a function of only one triangle side that preserves the localized nature of the relative velocity signature while also nicely separating linear from non-linear bias. We expect that this scheme will substantially lessen the computational burden of finding the relative velocity in the 3PCF. The relative velocity's 3PCF signature can be used to correct the shift induced in the galaxy-galaxy correlation function so that no systematic error due to this effect is introduced into the BAO as used for precision cosmology.

20 pages, 12 figures, v2 matches that accepted in MNRAS; relative to v1, references updated and corrected, improved axis labeling in Figure 9

References in corpus (11)

• Dynamics of dark energy
• Improving Cosmological Distance Measurements by Reconstruction of the Baryon Acoustic Peak
• On the Robustness of the Acoustic Scale in the Low-Redshift Clustering of Matter
• MAGIC discovery of VHE Emission from the FSRQ PKS 1222+21
• Non-linear structure formation and the acoustic scale
• Large-scale BAO signatures of the smallest galaxies
• Hilltop Quintessence
• Three-Point Correlation Functions of SDSS Galaxies: Luminosity and Color Dependence in Redshift and Projected Space
• Slow-roll k-essence
• Supersonic Relative Velocity between Dark Matter and Baryons: A Review
• Low-mass suppression of the satellite luminosity function due to the supersonic baryon--cold-dark-matter relative velocity

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• Estimating Covariance Matrices for Two- and Three-Point Correlation Function Moments in Arbitrary Survey Geometries
• Evidence for an environment-dependent shift in the baryon acoustic oscillation peak
• Small-scale structure and the Lyman-$\alpha$ forest baryon acoustic oscillation feature
• A First Detection of the Connected 4-Point Correlation Function of Galaxies Using the BOSS CMASS Sample
• The clustering of galaxies in the SDSS-III Baryon Oscillation Spectroscopic Survey: higher-order correlations revealed by germ-grain Minkowski Functionals
• Galaxy Three-Point Correlation Functions and Halo/Subhalo Models
• Neutrino winds on the sky
• On the galaxy 3-point correlation function in Modified Gravity
• Detecting Baryon Acoustic Oscillations in Dark Matter from Kinematic Weak Lensing Surveys
• Spatial correlations of extended cosmological structures