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

Susmita Adhikari, Chun Yin Ricky Chue, Neal Dalal

Research output: Contribution to journalArticlepeer-review


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.

Original languageEnglish (US)
Article number009
JournalJournal of Cosmology and Astroparticle Physics
Issue number1
StatePublished - Jan 1 2015
Externally publishedYes


  • dark matter simulations
  • weak gravitational lensing

ASJC Scopus subject areas

  • Astronomy and Astrophysics


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