Accurately computing weak lensing convergence

Abstract

Weak lensing will play an important role in future cosmological surveys, including e.g. Euclid and SKA. Sufficiently accurate theoretical predictions are important for correctly interpreting these surveys and hence for extracting correct cosmological parameter estimations. We quantify for the first time in a relativistic setting how many post-Born and lens-lens coupling corrections are required for sub-percent accuracy of the theoretical weak lensing convergence for $z\le 2$ (the primary weak lensing range for Euclid and SKA). We do this by ray-tracing through a fully relativistic exact solution of the Einstein Field Equations which consists of randomly packed mass-compensated underdensities of realistic amplitudes. We find that including lens-lens coupling terms and post-Born corrections up to second and third order respectively is sufficient for sub-percent accuracy of the convergence along $94\%$ of the studied light rays. We also find that a significant percentage of the studied rays have post-Born corrections of size over $10\%$ of the usual gravitational convergence, ${\kappa }^{(1)}$, and several rays even have post-Born corrections several times the size of ${\kappa }^{(1)}$ at $z=2$.

5 pages, 4 figures. v2: More data added with figures and text changed appropriately. Overall results unchanged. v3: Significant changes to presentation to match published version. Overall results unchanged

References in corpus (8)

• Anti-lensing: the bright side of voids
• Luminosity distance in "Swiss cheese" cosmology with randomized voids: I. Single void size
• The luminosity distance-redshift relation up to second order in the Poisson gauge with anisotropic stress
• Light propagation in Swiss cheese models of random close-packed Szekeres structures: Effects of anisotropy and comparisons with perturbative results
• Impact of next-to-leading order contributions to CMB lensing
• Non-linear general relativistic effects in the observed redshift
• Gauge-Invariant Formalism of Cosmological Weak Lensing
• Weak lensing corrections to tSZ-lensing cross correlation

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