3D photometric cosmic shear

Thomas Kitching, A. F. Heavens, L. Miller

Research output: Contribution to journalArticlepeer-review

Abstract

Here we present a number of improvements to weak lensing 3D power spectrum analysis, 3D cosmic shear, that uses the shape and redshift information of every galaxy to constrain cosmological parameters. We show how photometric redshift probability distributions for individual galaxies can be directly included in this statistic with no averaging. We also include the Limber approximation, considerably simplifying full 3D cosmic shear analysis, and we investigate its range of applicability. Finally we show the relationship between weak lensing tomography and the 3D cosmic shear field itself; the steps connecting them being the Limber approximation, a harmonic-space transform and a discretization in wavenumber. Each method has its advantages; 3D cosmic shear analysis allows straightforward inclusion of all relevant modes, thus ensuring minimum error bars, and direct control of the range of physical wavenumbers probed, to avoid the uncertain highly non-linear regime. On the other hand, tomography is more convenient for checking systematics through direct investigation of the redshift dependence of the signal. Finally, for tomography, we suggest that the angular modes probed should be redshift dependent, to recover some of the 3D advantages.

Original languageEnglish
Pages (from-to)2923-2934
Number of pages12
JournalMonthly Notices of the Royal Astronomical Society
Volume413
Issue number4
DOIs
Publication statusPublished - Jun 2011

Keywords

  • cosmology: theory
  • large-scale structure of Universe
  • DARK ENERGY CONSTRAINTS
  • WEAK-LENSING TOMOGRAPHY
  • INTRINSIC ALIGNMENTS
  • MODIFIED GRAVITY
  • POWER SPECTRA
  • COSMOLOGY
  • IMPACT
  • MATTER
  • MODEL

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