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arXiv · 1407.1128

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

Susmita Adhikari·Chun Yin Ricky Chue·Neal Dalal
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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.

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Susmita Adhikari, Chun Yin Ricky Chue, Neal Dalal. 2014-07-04. Three-point galaxy-galaxy lensing as a probe of dark matter halo shapes. https://doi.org/10.1088/1475-7516%2F2015%2F01%2F009

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