Three-point galaxy-galaxy lensing as a probe of dark matter halo shapes

Abstract

We propose a method to measure the ellipticities of dark matter halos using the lens-shear-shear 3-point correlation function. This method is immune to effects of galaxy-halo misalignments that can potentially limit 2-point galaxy-galaxy lensing measurements of halo anisotropy. Using a simple model for the projected mass distributions of dark matter halos, we construct an ellipticity estimator that sums over all possible triangular configurations of the 3-point function. By applying our estimator to halos from N-body simulations, we find that systematic errors in the recovered ellipticity will be at the <5% fractional level. We estimate that future imaging surveys like LSST will have sufficient statistics to detect halo ellipticities using 3-point lensing.

9 pages, to be submitted to JCAP

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Cited by in corpus (7)

• Euclid. I. Overview of the Euclid mission
• Dark matter in galaxies
• Tracer-Field Cross-Correlations with $k$-Nearest Neighbor Distributions
• Tightening weak lensing constraints on the ellipticity of galaxy-scale dark matter haloes
• The shape of dark matter haloes: results from weak lensing in the Ultraviolet Near-Infrared Optical Northern Survey (UNIONS)
• Mapping dark matter and finding filaments: calibration of lensing analysis techniques on simulated data
• Ellipticities of Galaxy Cluster Halos from Halo-Shear-Shear Correlations