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Exploring Beyond ΛCDM with the Weak Lensing Power Spectrum and Bispectrum

Liantsoa F. Randrianjanahary, Chandrachud B. V. Dash

Abstract

In this article, we investigate the effect of systematics on weak lensing beyond the standard ΛCDM paradigm. Specifically, we consider the 2- and 3-point statistics of the shear field for the set of cosmological models, including CPL dark energy, interacting dark energy (IDE), and Hu-Sawicki f (R) modified gravity. We consider two major systematics such as photometric redshift uncertainty and intrinsic alignment A IA . Our findings are derived from the Fisher matrix. These results indicate that σ z and A IA can substantially degrade constraining power, especially for f (R) gravity. Moreover, it also highlights the critical role of higher-order statistics and the need for robust systematic control for future cosmological surveys.

Exploring Beyond ΛCDM with the Weak Lensing Power Spectrum and Bispectrum

Abstract

In this article, we investigate the effect of systematics on weak lensing beyond the standard ΛCDM paradigm. Specifically, we consider the 2- and 3-point statistics of the shear field for the set of cosmological models, including CPL dark energy, interacting dark energy (IDE), and Hu-Sawicki f (R) modified gravity. We consider two major systematics such as photometric redshift uncertainty and intrinsic alignment A IA . Our findings are derived from the Fisher matrix. These results indicate that σ z and A IA can substantially degrade constraining power, especially for f (R) gravity. Moreover, it also highlights the critical role of higher-order statistics and the need for robust systematic control for future cosmological surveys.
Paper Structure (22 sections, 66 equations, 5 figures, 2 tables)

This paper contains 22 sections, 66 equations, 5 figures, 2 tables.

Table of Contents

  1. Introduction
  2. Dark energy models beyond $\Lambda$CDM: background expansion and growth
  3. Unified description of the background expansion
  4. Linear growth of structure in beyond-$\Lambda$CDM models
  5. Weak lensing observables and observational systematics
  6. Two-point power spectra
  7. Tomographic weak lensing power spectrum
  8. Intrinsic alignments (IA)
  9. Photometric redshift uncertainties
  10. Weak lensing bispectrum formalism
  11. Matter bispectrum modeling
  12. Tomographic shear bispectrum
  13. Fisher matrix formalism for power spectrum and bispectrum
  14. Power spectrum Fisher matrix
  15. Bispectrum Fisher matrix
  16. ...and 7 more sections

Figures (5)

  • Figure 1: Left: redshift evolution of the scale-independent growth factor $f\sigma_8(z)$ for the three models considered. Data points atr taken from benisty2021quantifying Right: scale- and redshift-dependent growth $f\sigma_8(z;k)$ in Hu--Sawicki $f(R)$ with $\ln(f_{R0})=-5$ at $z=0.1$ for representative wavenumbers $k$.
  • Figure 2: Left: it shows the distribution of the source. The dashed line represents the pessimistic case; Right: Kernel of weak lensing field
  • Figure 3: Left: percentage of deviation of $C^{\gamma \gamma}_\ell$ from the two tomographic bins using various models to $\Lambda$CDM Right: same but for $C^{\epsilon\epsilon}_\ell$
  • Figure 4: Ellipses for CPL, IDE and $f(R)$ from Power Spectrum
  • Figure 5: Ellipses for CPL, IDE and $f(R)$ from Bispectrum