Retrieving the three-dimensional matter power spectrum and galaxy biasing parameters from lensing tomography

TL;DR

This paper develops statistical methods to extract the 3D matter power spectrum and galaxy biasing parameters from weak lensing tomography data, enabling better understanding of cosmic structure and galaxy-matter relationships.

Contribution

It introduces minimum variance estimators and a Bayesian approach for inverting noisy tomography correlation functions to probe deviations from a fiducial power spectrum.

Findings

Shear tomography can reveal baryonic effects on the nonlinear matter power spectrum at low redshift.

The methods can constrain galaxy biasing parameters up to redshift 0.5.

A survey area of at least 1000 square degrees is needed for robust results.

Abstract

With the availability of galaxy distance indicators in weak lensing surveys, lensing tomography can be harnessed to constrain the three-dimensional (3D) matter power spectrum over a range of redshift and physical scale. By combining galaxy-galaxy lensing and galaxy clustering, this can be extended to probe the 3D galaxy-matter and galaxy-galaxy power spectrum or, alternatively, galaxy biasing parameters. To achieve this aim, this paper introduces and discusses minimum variance estimators and a more general Bayesian approach to statistically invert a set of noisy tomography 2-point correlation functions, measured within a confined opening angle. Both methods are constructed such that they probe deviations of the power spectrum from a fiducial power spectrum, thereby enabling both a direct comparison of theory and data, and in principle the identification of the physical scale and redshift of deviations. By devising a new Monte Carlo technique, we quantify the measurement noise in the correlators for a fiducial survey, and test the performance of the inversion techniques. We conclude that a shear tomography analysis of near future weak lensing surveys promises fruitful insights into the effect of baryons on the nonlinear matter power spectrum at z<~0.3 around k~2 h/Mpc, and into galaxy biasing (z<~0.5). However, a proper treatment of anticipated systematics -- not included in the mock analysis but discussed here -- is likely to reduce the signal-to-noise in the analysis so that a robust assessment of the 3D matter power spectrum probably asks for a survey area of at least 1000 sdeg. [Abridged]