FAst STatistics for weak Lensing (FASTLens): Fast method for weak lensing statistics and map making

S. Pires, J. L. Starck, A. Amara, R. Teyssier, A. Réfrégier, J. Fadili

Research output: Contribution to journalArticlepeer-review

48 Scopus citations

Abstract

With increasingly large data sets, weak lensing measurements are able to measure cosmological parameters with ever-greater precision. However, this increased accuracy also places greater demands on the statistical tools used to extract the available information. To date, the majority of lensing analyses use the two-point statistics of the cosmic shear field. These can be either studied directly using the two-point correlation function or in Fourier space, using the power spectrum. But analysing weak lensing data inevitably involves the masking out of regions, for example to remove bright stars from the field. Masking out the stars is common practice but the gaps in the data need proper handling. In this paper, we show how an inpainting technique allows us to properly fill in these gaps with only Nlog N operations, leading to a new image from which we can compute straightforwardly and with a very good accuracy both the power spectrum and the bispectrum. We then propose a new method to compute the bispectrum with a polar fft algorithm, which has the main advantage of avoiding any interpolation in the Fourier domain. Finally, we propose a new method for dark matter mass map reconstruction from shear observations, which integrates this new inpainting concept. A range of examples based on 3D N-body simulations illustrates the results.

Original languageEnglish (US)
Pages (from-to)1265-1279
Number of pages15
JournalMonthly Notices of the Royal Astronomical Society
Volume395
Issue number3
DOIs
StatePublished - May 2009
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

Keywords

  • Dark matter
  • Methods: data analysis
  • Methods: statistical

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