Complete super-sample lensing covariance in the response approach
Abstract
We derive the complete super-sample covariance (SSC) of the matter and weak lensing convergence power spectra using the power spectrum response formalism to accurately describe the coupling of super- to sub-survey modes. The SSC term is completely characterized by the survey window function, the nonlinear matter power spectrum and the full first-order nonlinear power spectrum response function, which describes the response to super-survey density and tidal field perturbations. Generalized separate universe simulations can efficiently measure these responses in the nonlinear regime of structure formation, which is necessary for lensing applications. We derive the lensing SSC formulae for two cases: one under the Limber and flat-sky approximations, and a more general one that goes beyond the Limber approximation in the super-survey mode and is valid for curved sky applications. Quantitatively, we find that for sky fractions f_(sky) ≈ 0.3 and a single source redshift at z_S=1, the use of the flat-sky and Limber approximation underestimates the total SSC contribution by ≈ 10%. The contribution from super-survey tidal fields to the lensing SSC, which has not been included in cosmological analyses so far, is shown to represent about 5% of the total lensing covariance on multipoles ℓ_1,ℓ_2 ≳ 300. The SSC is the dominant off-diagonal contribution to the total lensing covariance, making it appropriate to include these tidal terms and beyond flat-sky/Limber corrections in cosmic shear analyses.
Additional Information
© 2018 IOP Publishing Ltd and Sissa Medialab. Received 21 December 2017; Accepted 31 May 2018; Published 11 June 2018. We thank Kazuyuki Akitsu, Fabien Lacasa, Yin Li, Takahiro Nishimichi, and Masahiro Takada for useful comments and discussions. FS acknowledges support from the Starting Grant (ERC-2015-STG 678652) "GrInflaGal" from the European Research Council. EK acknowledges support from NASA grant 15-WFIRST15-0008 Cosmology with the High Latitude Survey WFIRST Science Investigation Team (SIT). Some of the results in this paper have been derived using the HEALPix [63] package.Attached Files
Submitted - 1711.07467.pdf
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Additional details
- Eprint ID
- 86979
- Resolver ID
- CaltechAUTHORS:20180611-152552208
- 678652
- European Research Council (ERC)
- 15-WFIRST15-0008
- NASA
- Created
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2018-06-11Created from EPrint's datestamp field
- Updated
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2022-07-12Created from EPrint's last_modified field