The source-lens clustering effect in the context of lensing tomography and its self-calibration

Abstract

Cosmic shear can only be measured where there are galaxies. This source-lens clustering (SLC) effect has two sources, intrinsic source clustering and cosmic magnification (magnification/size bias). Lensing tomography can suppress the former. However, this reduction is limited by the existence of photo-z error and nonzero redshift bin width. Furthermore, SLC induced by cosmic magnification cannot be reduced by lensing tomography. Through N-body simulations, we quantify the impact of SLC on the lensing power spectrum in the context of lensing tomography. We consider both the standard estimator and the pixel-based estimator. We find that none of them can satisfactorily handle both sources of SLC. (1) For the standard estimator, SLC induced by both sources can bias the lensing power spectrum by O(1)-O(10)%. Intrinsic source clustering also increases statistical uncertainties in the measured lensing power spectrum. However, the standard estimator suppresses intrinsic source clustering in the cross-spectrum. (2) In contrast, the pixel-based estimator suppresses SLC through cosmic magnification. However, it fails to suppress SLC through intrinsic source clustering and the measured lensing power spectrum can be biased low by O(1)-O(10)%. In short, for typical photo-z errors (sigma_z/(1+z)=0.05) and photo-z bin sizes (Delta_z^P=0.2), SLC alters the lensing E-mode power spectrum by 1-10%, with ell~10^3$ and z_s~1 being of particular interest to weak lensing cosmology. Therefore the SLC is a severe systematic for cosmology in Stage-IV lensing surveys. We present useful scaling relations to self-calibrate the SLC effect.

13 pages, 10 figures, Accepted by APJ

References in corpus (13)

• Dark energy constraints from cosmic shear power spectra: impact of intrinsic alignments on photometric redshift requirements
• Effects of Baryons and Dissipation on the Matter Power Spectrum
• Cosmology with Weak Lensing Surveys
• Potential sources of contamination to weak lensing measurements: constraints from N-body simulations
• Handbook for the GREAT08 Challenge: An image analysis competition for cosmological lensing
• Baryons, Neutrinos, Feedback and Weak Gravitational Lensing
• Accounting for baryonic effects in cosmic shear tomography: Determining a minimal set of nuisance parameters using PCA
• The removal of shear-ellipticity correlations from the cosmic shear signal via nulling techniques
• The Gravitational Shear--Intrinsic Ellipticity Correlation Functions of Luminous Red Galaxies in Observation and in the $\Lambda$CDM Model
• Self Calibration of Tomographic Weak Lensing for the Physics of Baryons to Constrain Dark Energy
• Lensing Bias in Cosmic Shear
• Redshift and Shear Calibration: Impact on Cosmic Shear Studies and Survey Design
• LeMoMaF: Lensed Mock Map Facility

Cited by in corpus (8)

• Cosmological Simulations for Combined-Probe Analyses: Covariance and Neighbour-Exclusion Bias
• Statistical and Systematic Errors in Measurement of Weak-Lensing Minkowski Functionals: Application to Canada-France-Hawaii Lensing Survey
• KiDS-1000: cross-correlation with Planck cosmic microwave background lensing and intrinsic alignment removal with self-calibration
• Euclid and KiDS-1000: Quantifying the impact of source-lens clustering on cosmic shear analyses
• Weak Lensing Magnification Reconstruction with the Modified Internal Linear Combination Method
• Deep lensing with a twist: E and B modes in a field with multiple lenses
• Pixelization effects in cosmic shear angular power spectra
• Non-linear infusion of intrinsic alignment and source clustering: impact on non-Gaussian cosmic shear statistics