Enhancing the cosmic shear power spectrum

Fergus Simpson, Joachim Harnois-Déraps, Catherine Heymans, Raul Jimenez, Benjamin Joachimi, Licia Verde

Research output: Contribution to journalArticlepeer-review


Applying a transformation to a non-Gaussian field can enhance the information content of the resulting power spectrum, by reducing the correlations between Fourier modes. In the context of weak gravitational lensing, it has been shown that this gain in information content is significantly compromised by the presence of shape noise. We apply clipping to mock convergence fields, a technique which is known to be robust in the presence of noise and has been successfully applied to galaxy number density fields. When analysed in isolation the resulting convergence power spectrum returns degraded constraints on cosmological parameters. However, substantial gains can be achieved by performing a combined analysis of the power spectra derived from both the original and transformed fields. Even in the presence of realistic levels of shape noise, we demonstrate that this approach is capable of reducing the area of likelihood contours within the Ωm - σ8 plane by more than a factor of 3.
Original languageEnglish
Pages (from-to)278-285
JournalMonthly Notices of the Royal Astronomical Society
Issue number1
Publication statusPublished - 1 Feb 2016


  • gravitational lensing: weak
  • cosmological parameters
  • dark matter
  • large-scale structure of Universe


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