A new measure for weak-lensing flexion

Yuki Okura, Keiichi Umetsu, Toshifumi Futamase

Research output: Contribution to journalArticlepeer-review

57 Citations (Scopus)


We study the possibility of using the octopole moment of gravitationally lensed images as a direct measure of the third-order weak gravitational lensing effect, or the gravitational flexion. It turns out that there is a natural relation between flexion and certain combinations of octopole/higher multipole moments that we call the higher order lensing image's characteristics (HOLICs). This will allow one to measure directly flexion from observable octopole and higher multipole moments of background images. We show based on simulated observations how the use of HOLICs can improve the accuracy and resolution of a reconstructed mass map, in which we assume Gaussian uncertainties in the shape measurements estimated using deep i′-band data of blank fields observed with Suprime-Cam on the Subaru telescope.

Original languageEnglish
Pages (from-to)995-1002
Number of pages8
JournalAstrophysical Journal
Issue number2 I
Publication statusPublished - 2007 May 10
Externally publishedYes


  • Cosmology: theory
  • Dark matter
  • Galaxies: clusters: general
  • Gravitational lensing

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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